/ohm/ - Electronics General: complimentary JFET edition

[Anonymous No.2565489]

Thread overcooked:>>2559805

>I'm new to electronics. Where to get started?
It is an art/science of applying principles to requirements.
Find problem, learn principles, design and verify solution, build, test, post results, repeat.

>Incredibly comprehensive list of electronics resources:
https://github.com/kitspace/awesome-electronics
Additional resources below:

>Project ideas:
https://adafruit.com
https://instructables.com/tag/type-id/category-technology/
https://makezine.com/category/electronics/
https://hackaday.io

>Don't ask, roll:
https://github.com/Rocheez/4chan-electronics-challenges/blob/master/list-of-challenges.png

>Archive of Popular Electronics magazines (1954-2003):
https://worldradiohistory.com/Popular-Electronics-Guide.htm
>Microchip Tips and Tricks PDF:
https://ww1.microchip.com/downloads/en/devicedoc/01146b.pdf
>Li+/LiPo batteries required reading:
https://www.elteconline.com/download/pdf/SAFT-RIC-LI-ION-Safety-Recommendations.pdf

>Books:
https://libgen.rs/

>Principles (by increasing skill level):
Mims III, Getting Started in Electronics
Geier, How to Diagnose & Fix Everything Electronic
Kybett & Boysen, All New Electronics Self-Teaching Guide
Scherz & Monk, Practical Electronics for Inventors (arguably has minor issues with mains grounding)
Horowitz and Hill, The Art of Electronics

>Recommended Design/verification tools:
KiCAD 6+
Circuitmaker
Logisim Evolution

>Recommended Components/equipment:
Octopart
eBay/AliExpress sellers, for component assortments/sample kits (caveat emptor)
Local independent electronics distributors
ladyada.net/library/procure/hobbyist.html

>More related YouTube channels:
mjlorton
jkgamm041
EcProjects
Photonvids
sdgelectronics
paceworldwide

>microcontroller specific problems?
>>>/diy/mcg
>I have junk, what do?
Shitcan it
>consumer product support or PC building?
>>>/g/
>household/premises wiring?
More rules-driven than engineering, try /qtddtot/ or sparky general first
>antigravity and/or overunity?
Go away

[Anonymous No.2565501]

[Anonymous No.2565507]

>>2565501
fake you'd never go that slow on a highway

[Anonymous No.2565512]

>>2565507
You would if you saw tickle-me Elmo's fire or balls lightning.

[Anonymous No.2565515]

>>2565474
No it's not. I did that by hand. Pic related is from my solution. The thioruea doesnt seem to do squat so this is electroplating. I get a dull grey color doesnt layer evenly and in the edges will build Crystal's which was cool to see. The center traces in the picture arent plated but that's hard to tell.

[Anonymous No.2565517]

>>2565515
Just watch out for whiskers. They're hard to see.

[Anonymous No.2565519]

How to explain a grandmother what's an impedance?

[Anonymous No.2565521]

>>2565517
What do you mean by whiskers?

[Anonymous No.2565522]

>>2565519
molasses has more impedance than honey has more impedance than water.

[Anonymous No.2565523]

>>2565519
Show her this and then push her down the stairs.

[Anonymous No.2565525]

>>2565519
Tell her imagine trying to get up from a chair. Impedance is gravity making it hard to get up. In the electrical world impedance is the resistance of change.

[Anonymous No.2565526]

>>2565521
Tin whiskers.

[Anonymous No.2565527]

>>2565523
wrong webm lmao

[Anonymous No.2565528]

>>2565526
Shouldnt be too hard. I need to figure out this Thioruea stuff though. Maybe I need a heavy concentration not sure.

[Anonymous No.2565530]

>>2565528
is it real? you know how it is with the chinese. I think it may be identifiable by a blue flame test

[Anonymous No.2565531]

>>2565530
I am unsure if it is real I've notice some shine differences on the copper but no tin deposit. I have never done a blue flame test and I do not know if it is real.

[Anonymous No.2565533]

I have 3 separate heating pads connected to a 5v 1A psu which is good enough for my heating needs. I want to make sure that they draw more or less the same amount, I was considering feeding each pad with a 1n5157 diode. But should I use a mosfet instead (like a 2n7000)

[Anonymous No.2565534]

>>2565528
https://www.youtube.com/watch?v=Hsw3lOnHaas

[Anonymous No.2565540]

>>2565525
"Why does gravity need to be 50?"

[Anonymous No.2565550]

>>2565540
Because the system that uses it was based on that. It is to allow signals to pass through with little reflection and the best power possible. Not all systems use 50. Some use 75 I believe and there is another one but I forget what that is.

[Anonymous No.2565552]

>>2565540
It doesn't have to be, it's just that all our crap is designed with that in mind. Things pushed up with certain force go up a certain amount. Moon lander built for less g, etc.

[Anonymous No.2565555]

>>2565550
If you mean RF pcbs and interlinks and stuff, yeah, 30 is sometimes common too, and up real high sometimes for miniature bespoke stuff. For an audio system, 4-8Ω is plenty common

[Anonymous No.2565560]

>>2565550
How can current get reflected while going through the conductor like a copper line?

[Anonymous No.2565562]

>>2565560
Well when you do things in books they only show you real idealized models but cables are not ideal. They have their own conductance inductance resistance and much of that depends on frequency what you are sending through A current can be considered a wave even if it is DC in the few picoseconds you turn a circuit on. Things dont change immediately in AC this is more pronouned. Its hard to explain but some people use things like gautar strings to show how waves in a wire can cause some issues. Youd be surprised that at certain frequencies for a specific wire the end can be a short circuit for a signal even though the cable is open on the end.

[Anonymous No.2565564]

>>2565560
like this

[Anonymous No.2565565]

>>2565564
I'll never understand how people can just sit there and let things go to shit. Like just turn the damn thing off.

[Anonymous No.2565567]

>>2565564
E-STOP wtf

[Anonymous No.2565568]

>>2565565
He looks like he has down syndrome. A real mongoloid. He eats dogs and batsoups.

If it were up to me, he'd go right in the fucking volcano.

[Anonymous No.2565569]

>>2565567
JUST PULL THE PLUG FATTY

[Anonymous No.2565573]

>>2565564
I can watch people being converted into piles of steamy meat but I can't stand people eating so much just for the show. How so?

[Anonymous No.2565574]

>>2565531
just dissolve a little in a mL of alcohol and burn it (outside). sulphur compounds should produce a bright blue flame, like how borax makes a green flame

[Anonymous No.2565575]

>>2565573
You might have a repressed memory of some slob slathering their face in barbecue sauce and licking their fat, greasy fingers while burping and farding and shidding.

[Anonymous No.2565590]

are these things safe?

[Anonymous No.2565593]

>>2565590
They look like worried faces, but there's a Philips logo. 50/50 ask big clove

[Anonymous No.2565594]

>>2565593
>Phillips
>good

[Anonymous No.2565596]

How can you live in a place with just 110V? What if you have a boiler, and then you use cooking plate with an oven?

[Anonymous No.2565598]

>>2565594
>there's a logo
>as opposed to no logo
>or Bangdingow Elite International Electronics Plantation, Guangdong CN
meh

[Anonymous No.2565604]

>>2565596
>live in a place with just 110V?
I don't think anyone does. if they actually do
>if you have a boiler, and then you use cooking plate with an oven?
you use breakers twice as big.

[Anonymous No.2565649]

Can a LCD or LED panel be replaced with an OLED panel?

[Anonymous No.2565654]

>>2565649
they are not universally interchangeable, unless they use VGA / hdmi / etc.
if you are lucky, maybe you can replace the display if you know the exact part number and the same manufacturer just offers a switch in with the same pins.

[Anonymous No.2565666]

>>2565596
American hu
Houses run on 240. Then it it halved and turned into two phases for electrical load balancing or something. For heavy loads like washer dryer ac etc they get the full 240 but general household electricals only have 120. You can usually tell the difference by the outlet design 240 units usually look different.

[Anonymous No.2565675]

>>2565666
Don't try to explain it to them.
Next you'll be drawing a diagram to show the difference between a ring circuit and a radial circuit.

[Anonymous No.2565684]

>>2565540
The intrinsic impedance of a simple dipole antenna is 50Ω if I recall, so it's useful to have all your radio circuits be 50Ω. It drops out of Maxwell's equations as the Planck impedance divided by an integer and/or pi.

Don't ask me why TV cables are 75Ω.

[Anonymous No.2565689]

>>2565684
dipoles are like 350-600 ohm, they always need 1:9 baluns

[Anonymous No.2565692]

>>2565684
Something like this. Didnt finish my EM course. Not sure why it was so rough.

[Anonymous No.2565740]

Do animatronics count as ohm and if so, how the fuck do I into them - specifically small diorama/fig based shit? I literally can't find anything animatronic related online without 10 billion FNAF links

[Anonymous No.2565743]

>>2565740
maybe >>>/diy/mcg/

[Anonymous No.2565781]

>>2565675
What's the difference between a ring circuit and a radial circuit? This is too complicated for my primitive American brain. Please help.

[Anonymous No.2565839]

I need to power an MCU from dual power AC+battery. One way to do that is to add back to back protective diodes. But that will cause VCC fluctuate with current and is just plain yucky. I need an accurate and stable VCC. Is there a better way?

[Anonymous No.2565841]

>>2565666
What about single phase earth return in rural areas? Is that just 120V?

[Anonymous No.2565892]

How to diy a remote starter for a diesel generator? There's an electric starter already present, but you need to pull the choke lever and such. Pic is not exactly mine, but similar.

[Anonymous No.2565893]

>>2565892
servo or stepper or some type of actuator to do the choke lever. relay to do the starter. something to detect RPM. set the choke. engage the starter for a moment, check RPM and either starter again or adjust choke accordingly.

How far away is it? Close enough for your wifi then there are many ways to do all this. Further away you need Xbee, Zigbee, LORA, whatever.

I'm too lazy to do your googling, but there are probably videos and blogs to hold your hand.

[Anonymous No.2565895]

>>2565893
He might have EMI issues after the generator is started.

[Anonymous No.2565896]

>>2565895
>He might have EMI issues after the generator is started.

you are in the /ohm/ thread. we laugh at EMI.

[Anonymous No.2565898]

>>2565896
I thought I was in /lgbt/ until you reminded me.

[Anonymous No.2565903]

>>2565781
Most of the modern world uses typical radial circuits, whereas bongland uses ring circuits.
Bongs use ring circuits to save money, because after that little war 85 years ago they couldn't afford to wire their homes correctly.
The typical American home is fed with a 48kW-96kW connection, the typical bong home is only 20kW-28kW.
An American can fire up the electric oven (4kW), the microwave (1.5kW), the kettle (1.5kW), the electric dryer (4kW), a hair dryer (1.5kW), a gaming PC at full tilt (1kW), a whole household of inefficient old lights (1.6kW) all while charging their EV (24kW). That's only 39.1kW, not even halfway to a typical modern American 96kW connection.
A bong cannot do this, as the ring of their ring circuit can only handle about 7kW, yet their kettles (3kW), hair dryers (3kW), and many other electric appliances actually use far more power than their American equivalent.
A bong can max out their whole-home ring circuit with just a hair dryer, a tea kettle, and one decent gaming computer.

Basically, the British electrical system is a crippled heap of shit.
The rest of Europe has it better, America has it better, the Japs have it better, South Africans have it better.
The bongs got the worst of all of it, with the most limitations, and the least safety.
>Our plugs are so much safer tha-ACK
Bong plugs are hardcore, they have to be as a band-aid measure because of how fucking stupid the ring circuit is to begin with.
Americans don't need a fuse at each plug because our wall outlets don't provide >2x the maximum power draw that's allowed from said plug.
Americans also don't have to rely on a single RCD, and have real circuit breakers.
When something trips, an American glances at the panel to see what went, a bong gets to wonder what in their ENTIRE HOME is causing the issue.

How can someone live in a place where they can't use 53 kettles simultaneously?
Bongland is basically Somalia with whites.

[Anonymous No.2565908]

>>2565903
Thanks for the rundown, Anon. Do bongs still play Doom on token ring networks?

[Anonymous No.2565917]

>>2565908
Of course, it's not like they have any other option.

[Anonymous No.2565923]

>>2565917
Those poor limey bastards. We ought to start a charity so we can bring them copper Romex and fiber/Ethernet. Then charge them 33% interest for the next 33 years in lieu of ceding their Canadian territory to the Republic of Florida.

[Anonymous No.2565930]

>>2565923
Won't do them any good, it's a country where you have to go to your local government to get approval to plant grass on your own property.
It's a place where the government can come in and tell you to replace your roof as often as they feel like, tell you to paint your fence the new shade of white they've approved, and if you don't comply they'll fine you into the ground then jail you when you fail to pay those fines.
Bongland is a fucking SHITHOLE, a horrific place where you cannot own property, but you do pay for the right to continue to pay the taxes for a place you want to live.
That is, you pay for property but you don't own it and don't have say over what you do with it.
If we bring them Romex, various councils will decide it doesn't fit the "rustic theme" of their entire country, and it won't be allowed to be used anywhere.

A bong paints their house a color they like: Fines, potential eviction from the community, potential jailtime.
A bong plants flowers on their property: Fines, potential eviction from the community, potential jailtime.
A bong installs modern windows for better insulation: Fines, potential eviction from the community, potential jailtime.
A bong replaces their ancient lead roof with a modern tin roof: Fines, potential eviction from the community, potential jailtime.
A bong parks anywhere but the driveway or garage on their own property: Fines, potential eviction from the community, potential jailtime.

Bongs have no freedom.

[Anonymous No.2565936]

>>2565930
We could send hundreds of baby Trump balloons to drop guns and pocket constitutions containing baggies of meth on soccer hooligans. Orange (man bad) revolution.

[Anonymous No.2565950]

>>2565936
Guns and Meth might do them some good.
From 2009 - 2019, there were 4,566,790 burglaries in the UK, an average of over 450,000 per year.
Of those 4.5 million burglaries, over 2 million were "hot," wherein they broke into a home while the homeowner was there.
That's over 200,000 HOT burglaries every year, in a country of 67 million people.

So, ~670 burglaries per 100k residents, over 300 "hot" burglaries per 100k residents, per year.
Whereas in the US: ~330 burglaries per 100k residents, of which 50 are "hot," per year.

Chances of a break-in, US compared to UK: 49%
Chances of a break-in while you're home, US compared to UK: 17%

If you know people can't defend themselves, and that they themselves will be punished if they harm you while you commit your crimes, you don't have much incentive to not commit those crimes.

In many Euro countries, trucks aren't popular, they're too big and impractical for their needs.
In Bongland, trucks aren't popular because you can't put anything in the bed without it being stolen immediately in broad daylight.

Bongland, where the electricity goes in circles and your belongings are strictly temporary.

[Anonymous No.2565953]

>>2565841
I would assume the same still. You only need a 240 volt single phase then take a transformer and center tap it on the secondary.

[Anonymous No.2565976]

>bought some linear hall sensors
>plug into arduino
>wave some N45 neodynmium magnets at it
>no response
>output just flickers around 120
>test each one, one by one
>nothing
>try a potentiometer
>scales from 0 to 1023 just fine
Did I get a whole batch of duds or are magnets not strong enough for this sensor?

[Anonymous No.2565977]

>>2565953
In the US, SWER is pretty rare, but it's heaviest usage was not in rural or inaccessible areas at all, but instead Los Angeles, one of the largest and most heavily populated metropolitan areas in the world. A combination of rapid expansion and a naturally divisive landscape made it an appealing and inexpensive option; at one time nearly half of Los Angeles was fed by SWER.

The implementations vary, especially as it's now an "archaic" topic in the US.
Some early use of SWER in the US did only provide 120V, but those were always rare and highly I doubt any are still around.
More common is the scaled-down traditional network, where a single high-voltage line is fed to the area, and then split-phase 240V "normal" power is distributed from a central point.
This wasn't always the common or easy way to do it, but nowadays it's a no-brainer to stick what is basically a teeny substation in any random mountain town with a dozen households.

[Anonymous No.2565979]

Do you play with e-ink displays here? I'd like to make a control display for several sensors.

[Anonymous No.2566017]

>>2565976
did you wire it up properly?

[Anonymous No.2566032]

>>2566017
> open drain output
> you need a pull up resistor
>>2565997

[Anonymous No.2566121]

>>2565976
magnets easily overwhelm those things. Iirc, pinout should be Vcc, GND, and Vout. I don't remember needing any resistors, just plug straight to 5V regulator.

Amazon parts are 90% scams, much worse than even ali or ebay so i'm betting you just got chink'd.

[Anonymous No.2566125]

Is it a good first project?
https://youtu.be/C7blZigaaaA

[Anonymous No.2566139]

>>2566125
Nvm I found better ones
https://youtu.be/9q0mh3y_XBc
https://youtu.be/QarizoUnRfk

[Anonymous No.2566191]

>>2566139
Sure it could be cool. I have a small cheap chinese station myself so I wouldnt make one personally but if you think you are up to the task I like the aluminum one myself.

[Anonymous No.2566211]

Anyone familiar with active balancing circuits for lithium battery packs? Just learnt about lossless balancing ICs like the ETA3000, which says it can handle 2A balancing current. Is there a good rule of thumb for considering a balancing current to charge/discharge current ratio? I'm guessing that ratio will be under 5%, but I'm looking at 200A or more and I'm not sure if 1% is being too optimistic. Shunting more than 2A with linear balancing during charging might get kinda hot too.

[Anonymous No.2566412]

I was trying to measure how many volts the fly swatter circuit is... So how many volts is it. I'm supposed to get it to 8kv looks like it's 1700 volts.
I got 100 1n4007 diodes, those will be good for the voltage multiplier right...

[Anonymous No.2566440]

>>2566412
youe meter isnt fast enough to catch a spike by the looks anyway. scope it properly with high imedpance vooltage divider or some other step down method

[Anonymous No.2566442]

I don't have an oscilloscope and want to buy cheap chinesium one. How to figure out if this bandwidth and sampling rate will be enough for my needs playing with optic fibers, frequencies and lasers? This one has amazing reviews all over youtube and I'm poor.

[Anonymous No.2566447]

>>2566440
Thank you but i'm not sure what that is... Is it a circuit? I do have a breadboard and a bunch of resistors but I think its faulty because the breadboard sparks when I turn the thing on...I'm waiting for another breadboard through the mail.

[Anonymous No.2566475]

>>2566412
>those will be good for the voltage multiplier right...

nope, they're 1000V max.
if it really is 1700V, then you gotta lower it by lowering battery voltage, or adding zeners or resistors to secondary.
also, it's AC but your meter is on DC.
and 600V is your meter's max on both AC and DC, so you'd need to add a resistor in series with your meter to measure anything over that.

[Anonymous No.2566476]

Anon. How do I solve for R1 and R2?

[Anonymous No.2566477]

>>2566476
Proper orientation

[Anonymous No.2566478]

>>2566412
>>2566475
>add a resistor in series

since you're a noob, i'll explain better.
- find input impedance of your meter.
- assuming it's 10M, if you add a 10M resistor in series, it'll show voltages that are half of what they really are.
- so look at display and multiply by 2.
- that's what the other nerd meant when he mentioned ''vooltage divider''.

[Anonymous No.2566482]

>>2566476
>>2566477
THIS
IS
/DIY/

[Anonymous No.2566488]

>>2566477
We really don't help for homework here pal this would be the second one youve asked for so far. But I am too baked to care or even read your paper. So give me the values you do know and I'll tell you how to solve it.

[Anonymous No.2566501]

>>2566488
Sry.
I made a mistake in the drawing. It's supposed to be a trimmer.
Anyways. This is partly how it's supposed to be done.
Don't bother with me. i'll
figure this out.

[Anonymous No.2566537]

>>2565489
What's the benefit of having an air pump instead of a fan blowing right in the handle? I'm looking to buy my first hot air station and this one seems the best but I wouldn't know the difference. I'd certainly get one which has a transformer inside instead of the mosfet supplied ones.

[Anonymous No.2566553]

I want to make a multi room speaker system for my hovel as cheaply as possible. My best idea right now is to get a handful of old raspberry pis and cheap pc speakers and then use some software like snapcast. Any ideas how I could do it cheaper/better?

One thing I can think of is getting a cheaper Rpi alternative, but I don't know of any that have USB-A + 3.5mm jack + WiFi

[Anonymous No.2566554]

>>2565489
I have a retarded grounding/shielding question, and figure that while you guys are having a good laugh at my expense I can probably get better advice here than elsewhere.
I'm looking to improve the shielding in a solid body electric guitar, and the gold standard appears to be using copper foil or copper foil tape to create something of a faraday cage for the pickup cavity and controls. Obviously I should shield the underside of the pickguard and the pickguard cavity, but since I also run a ground through a hole in the cavity to the claw on the back of the guitar, should I also be shielding the claw/trem cavity as well? I don't tend to see this done on tutorials, but the guitar tech world is also full of retarded "we've done it this way for 50 years" and "trust me it improves the tone" stuff so I thought I'd ask people that work with electronics instead of continuing to run in circles.
>tl;dr shielding guitar pickup cavity, should I be shielding the claw cavity as well or not?

[Anonymous No.2566555]

>>2566553
You think a raspberry pie could drive a bunch of home speakers? You need an amp dude. There are these amp boards which have bluetooth in them. You need to wire all of them speakers or there's no way you could sync a bunch of Pies.

https://www.aliexpress.com/item/1005003240554833.html?spm=a2g0o.productlist.main.13.506156ceaGx0YO&algo_pvid=18f494a7-913e-4e73-aa86-2d4f87589640&algo_exp_id=18f494a7-913e-4e73-aa86-2d4f87589640-6&pdp_ext_f=%7B%22sku_id%22%3A%2212000030571498838%22%7D&pdp_npi=3%40dis%21RON%2174.94%2157.7%21%21%21%21%21%402102196716769093737337086d06e3%2112000030571498838%21sea%21RO%21730770497&curPageLogUid=EVZbwxT4aQHK

You can try to find them locally where you're from on the craigslist equivalent or electronics store not necessarily have to wait 1 month for it.

[Anonymous No.2566560]

>>2566553
And get some fuckin speakers they're cheap as fuck, not 3w computer speakers. Look for 30 or 40w wall speakers

[Anonymous No.2566565]

>>2566554
It would be better to make sure all of your grounds are good, including the pot housings. If you want to go bonkers, use shielded wiring

[Anonymous No.2566570]

>>2566565
Grounds are already done and good (I've checked ground paths on it in the past and am just redoing them now to do the shielding, they are just classic Fender star grounding to volume pot and claw), it is more to try and minimise shit coming in and messing with the pickups (play in some cramped places close to speakers and single coils need all the help they can get in that environment). I'm only asking because if I am going to do this, I want to do it right.

[Anonymous No.2566572]

>>2566555
I was thinking of usb powered speakers that could plug into the pi so there's no need for an external amp. There would be 1 pi+speaker combo per room with an extra pi acting as the server in a central location. Snapcast handles syncing the audio

[Anonymous No.2566574]

>>2566572
Ok whatever dude, I'd kill myself before I'll ever do that.

[Anonymous No.2566576]

>>2566570
Are your pickups single-coil or Humbuckers? Have you cleaned your input jack, pots and selector switch with contact cleaner? How tight is the 1/4" jack?

[Anonymous No.2566578]

>>2566576
and are you using a shielded 1/4" patch cable?

[Anonymous No.2566581]

>>2566576
It is actually being fully redone, it was previously a HSS Pacifica and I am setting it up to be HP90 with a coil split on the bridge humbucker. The singles were causing issues before even though they passed grounding tests, like I said in the post before they were really having difficulties with speakers (as is not uncommon with singles). I am going to be thoroughly cleaning both pots, the switch and the jack, and using industry standard shielded wire. I have done work on computer electronics in the past, but this is my first time in about 20 years working on "straightforward" circuits instead of just following the instructions to solder x chip into y slot.
>>2566578
Only phone connectors I use are shielded, why?

[Anonymous No.2566590]

>>2566581
>Only phone connectors I use are shielded, why?
Unshielded wires act like antennas and pick up EMI from surrounding equipment.

[Anonymous No.2566596]

>>2566590
Yeah, I shouldn't be having an issue on that front. I was introduced into this world by a sound and lighting boomer, and as a result unintended ground noise was made to me as air is to Adrian Newey. For the record, I know that I am overthinking this, but I have a paranoia of both over and under engineering things. I know that I could just isolate fucking everything inside in copper foil and call it a day, but I want to know if I am a retard for shielding the claw cavity when I am only running a ground to there, whereas all of the live electrics are in the pickup cavity. But then I think that there is a tunnel from the pickup cavity to the claw cavity, and so surely I should incorporate that in my cage, and I'm back to over engineering. I think talking through it has helped me think it through though, I might just shield the claw cavity for my own piece of mind and be done with it, it isn't like it will take much copper tape.

[Anonymous No.2566602]

>>2566596
Well, the pickup wires should already have a foil shield around them, so if you use shielded wiring for the rest of the electronics you won't have to worry about the pick guard or cavity shielding.

[Anonymous No.2566603]

>>2566602
Okay then. I will shield it to satisfy my paranoia but won't lose any more sleep over it. Thank you for talking it through with this old retard, anon.

[Anonymous No.2566606]

>>2566603
No problem, Anon. Don't beat yourself up too much. Retards just do things without asking questions first. I don't think you're retarded.

[Anonymous No.2566610]

>>2566606
Thanks anon, I know that on electrical stuff I am retarded because 99% of what I have learned is purely through experience working in events management and tinkering with broken circuit boards. I know that I am basically the electrical wiring version of some guy who can program you something to do whatever you want, as long as you can accept that a simple calculator program will have hundreds of lines of spaghetti code to just do a square root or something, because he never learned math.sqrt() in python or some shit. In my case it is over engineering circuits and housings. At least this guitar should sound sweet by the time I'm done setting it back up, going from stock ceramic HSS to Alnico II P90 and Alnico V humbucker should be a fun experience. Now to make you know I'm a retard, I'm going to all of this effort because the only Pacifica made in leftie is the student model, and I am born sinister.

[Anonymous No.2566615]

>>2566610
Don't sweat it, dude. There are plenty of engineers who break into a sweat when you hand them a tool and ask them to do something simple. The grass is greener, or some shit. One man's retard is another man's genius. lmao

The difference between single-coils and humbuckers is amazing so long as the string height is good. Hope it turns out great, Anon.

[Anonymous No.2566620]

>>2566615
Thanks anon, I've had a humbucker on the bridge already, but from what I have tried on other guitars the Alnico Vs sound a lot nicer than the ceramics. I chose Alnico II for the P90 to give it a bit of an older tone. My main strat is SSS but this is going from my "well it has a humbucker so I can play some Gibson tone songs sometimes" guitar to one that can actually make the sounds I'm looking for. It is also a fun journey in better understanding the technical side of the instrument I'm playing. Thanks again for the help.

[Anonymous No.2566624]

>>2566620
IMO, HSH config is the way to go. Something for you to experiment with.

[Anonymous No.2566631]

>>2566624
Fair enough anon, I might opt for that one day (the only plus side of being a leftie is that once you get used to feeding on the table scraps that are student guitars you can find them cheap and just make sure the wiring and pots are fine after buying them) but this one will be Humbucker/P90 with a coil split for now, I have enough acrylic to make a new pickguard in future if I want to try HSH and can just desolder grounds and swap out the plates. Already have a spare bridge humbucker as well, could use the single out of the old one and would just need a neck humbucker and I'd be good. Thanks for the chat, I lurked this thread and /gg/ for a few weeks (old habits die hard and I try to lurk moar before coming into a new thread) but this thread seemed to have actual discussion of electricals and electronics while /gg/ just seemed to be /mu/tards screaming at each other over whether anyone can play their instruments or some shit.

[Anonymous No.2566633]

Any opinions on the best/accurate digital multimeter? We use Snap-On brand at school but they're like $300. Im just a hobbyist at this point. I want to make guitar pedals and modular synths. Thanks.

[Anonymous No.2566641]

>>2566553
>a multi room speaker system for my hovel as cheaply as possible.

you can do it for zero dollars by using the telephone wires.
typical house cables have 4 or 6 conductors, but only 2 are used.
hook up one phone jack to an amp, and speakers to all the other sockets.
ethernet and cable TV jacks can be used as well.

and in case you didnt know, RasPis are selling with around 400% markup coz of a shortage.

[Anonymous No.2566651]

>>2566553
>a multi room speaker system for my hovel as cheaply as possible.

you can do it for zero dollars by using the telephone wires.
typical house cables have 4 or 6 conductors, but only 2 are used.
hook up one phone jack to an amp, and speakers to all the other sockets.
ethernet and cable TV jacks can be used as well.

and in case you didnt know, RasPis are selling with around 400% markup coz of a shortage of raspberries.

[Anonymous No.2566675]

>>2566651
Might have to find an alternative to raspberries. I want to run my 3d printer on a dedicated computer that will send it commands but I want it to be tiny.

[Anonymous No.2566682]

>>2566675
Thin clients are cheaper and x86_64.

[Anonymous No.2566687]

Why not to stick a position control on a powerful brushless motor and obtain super powerful servo for like 30 bucks?

[Anonymous No.2566688]

Wired up dome relay logic circuits today. Havent started on plc yet, but im already glad they exist lol

[Anonymous No.2566689]

>>2566675
If all you want is a remote interface, $5 worth of ESP32: https://github.com/luc-github/ESP3D

There's the Inovato Quadra, they've taken a cheap Android TV box and installed Armbian on it so it can be offered as a Pi alternative. Not overpriced at $35: https://www.inovato.com/
They're cool about it too, they even explain how to install their shit on other Android TV boxes: https://www.inovato.com/article/install
Depending on where you are, one of those other off-the-shelf Android boxes might be cheaper, then you can just slap their Armbian onto it and you're good to go.
I used this for mine, it was $29USD at the time: https://www.amazon.com/dp/B07SM8WTBT

OrangePi makes plenty of options, but they're a shit company with shit support, all they do is pump out as many designs as they can flood the market with, common Chink strategy.
Still, they can be solid and affordable choices depending on your needs. The OPi Zero 2 is popular enough, and the price is right: https://www.aliexpress.us/item/3256804171701489.html
Similar but "better" is their R1 variant: https://www.aliexpress.us/item/3256803383445323.html
They have other options, but diminishing returns in my opinion. Don't invest in hardware that can't be taken advantage of because the software side is so incomplete and shitty.

There's the LibreComputer lineup. I've heard mixed things about these, but I've never had anything bad to say about my potato. Great naming scheme as well.
Libre Le Potato: https://www.amazon.com/Libre-Computer-AML-S905X-CC-Potato-64-bit/dp/B074P6BNGZ/
Libre Tritium: https://www.amazon.com/Libre-Computer-Board-ALL-H3-CC-Tritium/dp/B07D4KTRWR
Libre Renegade: https://www.amazon.com/Libre-Computer-ROC-RK3328-CC-Renegade-Ethernet/dp/B078RMQYHS
The prices aren't far apart, but honestly the Renegade in "real usage" should kick the ass off the other two boards.

The list keeps going, these are just some common, popular, inexpensive options.
Or, find a real Pi: https://rpilocator.com/

[Anonymous No.2566690]

>>2566682
You're right some of these are pretty cheap. Any you might suggest?

[Anonymous No.2566692]

>>2566687
People do exactly this.
You can buy add-on boards to stick directly to the back of a common NEMA17 or 23 stepper.
They're not expensive, and are becoming more popular for "high-end" custom 3D printer setups, especially when speed is the goal.
The big Chink aftermarket printer electronics makers push them out cheap, BTT with their S42C, and MKS with the SERVO42C.
Both are derivative of the Mechaduino project: https://github.com/jcchurch13/Mechaduino-Firmware

[Anonymous No.2566693]

>>2566690
There are a billion of the fuckin' things, and you'll be looking at a used one unless you want to spend 2xRPi money anyway.
You need to compare specs of ones you find in your price range, shit loads of thin clients are NOT x86, ARM processors have been popular for over a decade now.
If you're overwhelmed or just don't want to fuck around, HP T620, stupid common and stupid cheap (don't pay more than $60, $40-$50 is normal).
There are better deals, but if you don't feel like hunting, it's hard to go wrong with the T620.

Personally, I'd sooner buy two Android boxes and stick Armbian on both of them for that same $60, but you do you, I don't know what your needs are.

[Anonymous No.2566694]

>>2566690
Dell Wyse 5060 is decent for a low-power machine. HP made some in the same class. Anything under $50, and it should come with at least 4GB RAM. You may or may not find them with a PSU brick. Keep in mind that they're low-power (~20W) machines. You probably want a quad-core CPU at the minimum.

[Anonymous No.2566702]

>>2566690
>>>/g/ is all over this btw

[Anonymous No.2566834]

>>2565903
Also, the 220v standard is also considered “more dangerous than necessary” even in bongland nowadays. Although, again, half the wire cross section can deliver the same wattage… saves some £s.

[Anonymous No.2566879]

>>2566690
>HP EliteDesk 800 G2 with PSU
>i5-6500 3.2GHz 8GB RAM
>No SSD/HDD
$74.99 / free shipping
https://www.ebay.com/itm/234760063685

[Anonymous No.2566902]

if I buy from digikey and one item in my cart is out of stock, and restocking in estimated 50 days, will my entire cart be delayed or will the cart be split in 2 packages?
also are the estimated dates accurate or are they just a generously overestimated?

[Anonymous No.2566912]

>>2566576
To be honest I think quarter inch jacks are pretty shit for noise reasons, they only make contact at small points around the socket. Everyone should swap to RCA, if not a proper radio coaxial connector.

>>2566633
>snap-on brand multimeter
Interesting nightmare you have introduced me to. Brymen make good meters at a reasonably good price, check them out. Flukes are somewhat better but a lot more expensive, unless the Fluke 101 is enough for your needs.
There’s also chink meters like Uni-T or Aneng, which to be honest are probably fine unless your boss is picky about such things.

There’s a big spreadsheet in the EEVblog forum full of multimeters, comparing all their features.

>>2566692
Well those are for steppers, not for BLDCs. Just intended to prevent step skipping. You can get a lot more torque and speed out of an actual BLDC.

[Anonymous No.2566977]

>>2566633
buying the cheapest 6000 count sacrificial meter isn't stupid (if you have a soldering iron, getting one with a thermocouple is nice if you want to check if it's temperature is calibrated, but the thermocouple could also be garbage), you could even go down to 2000 count if you genuinely don't know why you are buying a multimeter.
some meters are better at different things, some are electrical and automotive (they don't have low ranges you expect for electronics), if you want an all-around electronics meter, you need to look at the specs very carefully.
For an all around multimeter (with autoranging), I use an an870, but you could also go for a an8009 if it's much cheaper. If you want a fancier design there is kaiweets KM601 (note all these meters use the same chip inside, but that's not to say they are all the same).
If you want to buy some recycled batteries, you can buy a meter + other accessories from this site (the batch of 26650 lifepo4's looks pretty nice), but you should be able to find a cheap meter in a electronics or maybe even a dollar store if you are lucky.

[Anonymous No.2566980]

>>2566977
https://batteryhookup.com/collections/accessories/products/battery-hookup-digital-multimeter-w-battery-included

[Anonymous No.2566994]

>>2566633
I make guitar pedals and I have an Amprobe 37XR-A. There were cheaper back in the day but they're still cheaper than a snap-on or a real fluke

[Anonymous No.2566995]

>>2566596
Yes, shielding a cavity for only a ground wire is retarded. What are you going to shield it with, itself?

[Anonymous No.2567001]

>>2566995
You see I thought that was the case, but as the discussion that went on shows I was overthinking things like a retard. Thanks for the honesty anon.

[Anonymous No.2567008]

>>2566977
also the multimeter in the picture doesn't have a continuity tester, but even the mid range meters don't really have a great continuity sensor (it's at like 3 or a little bit more checks per second).
But you could build your own continuity sensor (or buy / make a really cheap light based senors).
https://www.youtube.com/watch?v=N2M-p-OGvPg

[Anonymous No.2567011]

>>2567001
The truth is that shielding a guitar doesn't really do much anyway. Pickups are inherently designed to pick up magnetic fields. Copper shielding won't help.
The best solution is to point the guitar in a direction with no power transformers.

[Anonymous No.2567018]

is it possible to put a battery powered microcontroller to deep sleep and wake it up at a set interval with a very low power timer?

[Anonymous No.2567023]

>>2567018
Your micro is probably already equipped with low power / sleep mode. Read the datasheet.

[Anonymous No.2567025]

>>2567018
Yes, this is a standard function of ESP microcontrollers.
>ESP.deepSleep(10e6);
I'm sure there are others that behave similarly.

It's important to know that if you snag the cheapest random ESP8266 or ESP32 dev board, it may not be well designed for low-power use. Many leave things like the USB-UART bridge powered full time or other stupid shit that causes them to waste power.
When not dealing with poor chinese design choices, you can get ESP32 deep sleep current down to 10uA.

[Anonymous No.2567028]

>>2567025
ATMega328, same, can get sleep current <1uA.
The common STM32 chips, same, <5uA with the common bluepill boards if they're not garbage-tier clones.
This is a normal thing most modern MCUs can do, even the ones that cost pennies.

[Anonymous No.2567035]

>>2566977
Thanks dude, was in the market for a new multimeter. I had a clone of the aneng one I think bcs it looked exactly like one of them when I was browsing the store rn and it writes VN9205 on it instead of AN. Anyway it was a non auto range and from rotating the button for so long it started crapping out. I disassembled it and resoldered all the lines if u know what I'm talking about but instead made it worse. I just ordered a green an870 from AliExpress on their official store. One Russian guy said it was a bit slow.

[Anonymous No.2567041]

>>2567035
an870 is not a perfect meter, it feels pretty cheap (I think I could write a long list of really tiny nitpicks I've noticed over time) but compared to meters that are 2-5x the price, it's a steal, especially when I'm not a professional, it's probably going to start collecting dust when I'm done with my projects.

[Anonymous No.2567047]

>>2567035
Zotek ZT111 is another AN8009 analog.

[Anonymous No.2567063]

>>2566537
A fan in the base could make the handpiece smaller without dropping air power, and/or make the blower larger without impeding ergonomics. Not saying they're doing that, but it does look somewhat slimmer if nothing else.

For the iron itself, consider something that uses cartridge tips, like T245s or T12s. They have better thermal performance.

[Anonymous No.2567148]

I need to slow down the RPM of a single phase 230VAC induction motor.
Do I need a VFD or is it enough to just put a capacitor in series with the motor?
And if the latter, how do I calculate the capacitance? Or is it easier to just trial and error it?

[Anonymous No.2567164]

>>2566501
Felt like giving it a shot.
I'm pretty sure this is corrent.
What are you studying anon?

[Anonymous No.2567178]

>>2567148
Capacitor might slow it down by 10%, maybe 15-20% if you're lucky. But significant changes require a VFD. Too high an impedance would result in a stalled motor.

[Anonymous No.2567189]

what sort of amperage i need to put through 28awg solid core wire to make it red hot so i can cut stuff with it?

[Anonymous No.2567192]

is it retarded to have current flowing into an output pin on an IC? the pin is active low, and I want an LED to be on while the pin is active (low). the pin specifically isn't tri-state so it's only an output. will pushing current into it potentially damage the chip?
is this something that would only really be answerable from the data sheet?
my idea is to just have the LED tied to 5V (through a resistor to not burn the LED) and then when the pin goes low, that will act as "ground" and turn on the LED.
i know i could probably do this with some kind of pull-down resistor, but i mainly wanna know if my concerns are unfounded or not lol.

[Anonymous No.2567197]

>>2567148
>>2567178
I was asking because supposedly this method is used in ceiling/room fans and such, where the speed control buttons simply switch between different combinations of capacitors, and they can usually slow down by a lot more than 10%.
The motor in question is a relatively small 30W fan taken from a decommissioned AC unit.
I'm only going to set the speed once, so I have no problem just trial and erroring the right combination of capacitors to get the speed I want.

[Anonymous No.2567201]

>>2567164
R1 makes sense, and i recognise the formula you used for r2 (Rt = (R1^-1 +R2&-1)^-1), but why is 1/Rt = 160, and not 1/160?

[Anonymous No.2567222]

>>2567197
Better schematic I guess, since that one has two windings.

[Anonymous No.2567276]

Help my probe is finally done. Need to make the amplifier for it and it needs two replacement components which should be here Wednesday but otherwise its complete.

[Anonymous No.2567289]

>>2567192
No nothing will break, it's perfectly fine because digital IO has push-pull output stage which means it can either push or pull current. There should be IO source and sink current limits in the datasheet and as long as you don't exceed those everything will be fine.

[Anonymous No.2567303]

>>2567063
I got this one with the extra package which includes replacements for both heating element and different iron tips

[Anonymous No.2567306]

>>2567276
Nice. Will you make a carrying case for it?

[Anonymous No.2567308]

>>2567306
I didnt really think about anything like that. It was just going to go into the tool box. I'm going to make the amplifier first then think about it.

[Anonymous No.2567309]

>>2567303
Yihua irons are based
I only ever really use the gun for heat shrink though

[Anonymous No.2567311]

>>2567308
It would help with scratches/scuffs, crushing the tube, and debris getting into the jack.

[Anonymous No.2567322]

>>2567311
It's pretty sturdy some kind of steel but yeah you're right I'll have to see what I can come up with.

[Anonymous No.2567410]

>>2567303
I would consider one with an IR plate or consider getting one. Prewarming boards especially with huge ground planes will make your work so much easier. Plus if you are clever you could convert it to a rework station with automated control and heating profiles.

[Anonymous No.2567450]

>>2565519
>How to explain a grandmother what's an impedance?
impedance is the "resistance" that changes due to the frequency of the applied stimulus.
this is true of all components, but is more noticable in some components than others at lower frequencies.
also, bake me some cookies.

[Anonymous No.2567466]

Would it be possible to detect the flipping of a segment in a flipdot display? Lets say i poke it with my fingers and flip a single dot?

[Anonymous No.2567476]

>>2567466
Does it maybe pull on a motor if not maybe a light sensor.

[Anonymous No.2567481]

what do you guys use to repair traces? Looking for something liquid. I tried to use a nickel conductive pen but i could never get it to work (like 1 in 14 times) - just repairing small game systems/computers etc

[Anonymous No.2567485]

>>2567481
magnet wire or kynar wire wrap

[Anonymous No.2567488]

>>2567476
is this a retarded bot?

[Anonymous No.2567492]

>>2567466
>>2567476
>>2567488
flipdots don't use motor, it's just magnet that flips around under external coil current (and stays there once flipped)

if you wanted to read that backwards by listening to current on the coil lines...good luck, they probably piggyback and diode drain

[Anonymous No.2567497]

>>2567492
Couldn't you detect the magnetic field polarity of the dot?

[Anonymous No.2567498]

>>2567497
yeah, but again it would require you to map all the way back from the specific coil(s), to the control matrix. Most of the time it's not possible because they save lines by combining rows and columns. Also they put diodes in, so external forces on the electromechanical stuff can't create internal reverse currents that break the driver

[Anonymous No.2567500]

>>2567492
I know its just a coils in a matrix. If not driven the drivers output should float right? So putting current sensing in a matrix should work aswell?

>>2567497
My hunch is, upon flipping the dot manually, there should be a tiny current. Im unable to measure because i dont have one.

>>2567498
One diode per row and column, not individual coils. Maybe disconnecting the diode with a transistor while not driving?

[Anonymous No.2567505]

Does this mean my opamp is working good? bottom is direct signal top is through the opamp

[Anonymous No.2567509]

>>2567500
>upon flipping the dot manually, there should be a tiny current.
def. but if its flipped too slowly it'd be nigh undetectable. Think of a guitar string unamplified

>>2567500
>If not driven the drivers output should float right?
sadly, most are either high-impedance input mode, or low/high output mode, not both.

>Maybe disconnecting the diode with a transistor while not driving?
this would work along with changing the driver to input mode between switching, and then back.

[Anonymous No.2567511]

>>2567505
it looks like your opamp is a wire, anon.

cane to show some scales on that y-axis? Or bias in some gain?

[Anonymous No.2567512]

>>2567481
For short distances, you can just use bare wire.
Observe the size of the trace… power supply devices may need thicker gauge.
>>2567485
> Wire wrap
Old guys have lots of this shit lying around from the 80s. You can use RJ11 telephone wire usually for longer runs.
i used to have this teflon coated wire i pulled out of a mainframe so the insulation didn’t shrink back under heat.

[Anonymous No.2567514]

>>2567505
>working good?
Working *well*
Depends on what you mean by “good”
You could overlay them to see if there is any phase shift or distortion. That would be double plus good.

[Anonymous No.2567521]

>>2567514
How do I set up an x/y of the difference using an old scope? Just hook everything up and put it in x/y mode?
>>2567511
Signal is from an ipod, less than a volt rms. Not sure exactly though. The opamp is used as a high impedance buffer.

[Anonymous No.2567531]

>>2567521
>The opamp is used as a high impedance buffer.
in that case, looks great. If you can export them to csv or put them on the same plot, you can zoom way in on the peaks and check.

[Anonymous No.2567552]

>>2567521
>Just hook everything up and put it in x/y mode?

X/Y mode is when you wanna make sexy licentious figures.
(some snobs pronounce it lissajous, pretending they speak french)
what you want is to push 2 buttons: invert ch.2, then set ADD on vertical mode.

[Anonymous No.2567557]

>>2567552
frere jacques, parlez vous nigger?

[Anonymous No.2567571]

>>2567552
or just plot A-B, obviously.

[Anonymous No.2567584]

>>2567201
Rt = 160
1/Rt = 1/160
1/Rt = 1/200 + 1/800
Therefore
Rt = 1/ (1/200 + 1/800)

[Anonymous No.2567589]

>>2567552
This, but usually the first thing you do is just adjust each channel to be the same v/div and move the channels (y/vert pos) so they are over top of one another and eyeball it.

In diff mode, if the difference is tiny, you can see it easier at, like, 1 μV/div (or whatever your scope can do)

[Anonymous No.2567643]

>>2567303
Still no cartridge tips. Check out the soldering stations on welectron, then look for chinky alternatives now that you know what you’re missing.

>>2567500
They’re push-pull, right? Or are they biased with a permanent magnet beneath each dot? Not sure how you’d have a push-pull matrix. Anyhow you could still use analog MUX ICs like the CD4053 to sample a bunch of different coil voltages listening for spikes if they’re floating. If they’re not floating, then you should still be able to measure a current spike/dip. Might miss the spike though.

Aside from making a matrix of hall sensors, you could consider making a measurement of the coil inductances, as those should change as a function of fit position. But that’s probably even more difficult.

[Anonymous No.2567703]

Any recommendations for hot tweezers? I want to replace the surface mounted caps on my Gamecube but all I can find online are either comically overpriced Hakko tips that aren't compatible with my Weller station and no-name chinese shit with no reviews and 50 duplicate listings. The caps are too small to really remove with a regular tip and regular tweezers, and I've seen videos online of people easily removing them with hot tweezers.

[Anonymous No.2567716]

>>2567703
I just rest the ~6mm edge of a T12 K tip against both pads and SMD caps just come off in one go. If you can find a similar tip it should be easy. If you're not worried about damaging the old parts, then just cut/crush the old caps in half and desolder each pad at a time.

[Anonymous No.2567718]

>>2567716
That's..... not a completely terrible idea. I have a second soldering iron, but I stopped using it because it was too hot for electronics (only had one temperature that went around 850-900, was what I bought years ago not knowing any better) and it kept burning shit.

[Anonymous No.2567737]

>>2567552
I was under the impression that I could compare two signals using x/y and the result should ideally be a perfectly linear diagonal line

[Anonymous No.2567738]

>>2567718
plenty of people just twist smd caps off the board
there's a method to it, I heard about it from one of the big names on yt but I can't remember which one

[Anonymous No.2567740]

>>2567737
that is true but I don't think it will tell you about phase, and smooth over many wavelengths. Also that's a much harder way to see tiny differences than just subtracting them

[Anonymous No.2567788]

I was thinking about how to make a high-power AC-to-DC lithium ion charger, and how bad at designing one from scratch I'd be. So instead I'm thinking of getting an off-the-shelf AC-to-DC power supply, and detaching the LV-side feedback from the optocoupler (assuming the switching controller is on the high-voltage side) and feeding it a custom feedback signal. Be that signal just a CC/CV combination from a pair of amplifiers and diodes, or a microcontroller making ADC and DAC alterations. Probably with op-amps in there and the DACs acting as the CC and CV references, just so the whole feedback loop isn't dependant on the response-speed of the MCU.

Here's a quick circuit I whipped up using a few I2S parts I happen to own. Delta-sigma and dual-channel makes some bits easier, but there's probably reasons not to use them. The built-in DACs and ADCs of something like an ESP32 might be usable.
Gain of the input current differential amplifier could be whatever, while the gain of the two error amplifiers should probably be in the realm of 40dB. Maybe as low as 20dB, considering there's already an error amp in the existing switching controller circuit, and there's a reasonable amount of delay between the switching and the optocoupler and everything. Having a higher low-frequency gain might be a requirement.

For example, say I want to make a 12S battery charger. I'd buy a 48V open-cage Meanwell supply (the parts in that should be rated to the 50.4V maximum), desolder the outer two pins of the optocoupler, and wire this board in. I wouldn't trust it to drop the output voltage below 30V, but for things like battery charging I think it would be fine. Might need to add some extra wires to the enable pin for fault detection.

Thoughts?

[Anonymous No.2567804]

I followed the advice some anon said and made a voltage divider to get the voltage, however I still can't get a clear reading...

[Anonymous No.2567812]

>>2567804
you need a proper scope m8. the voltage divider was to step down your expected spike down to like 10V peak so your scope can handle it and not blow up.

[Anonymous No.2567833]

>>2567812
sorry what is a scope... the volt meter?

[Anonymous No.2567863]

>>2567833
scope = oscilloscope

Your meter is designed to test voltage up to 600V. You need a high voltage probe that is compatible with your meter or oscilloscope to measure 10kV.

[Anonymous No.2567872]

>>2565489
>LT spice
bad, constrained, busted
>proteus
New, hot, sexy

[Anonymous No.2567873]

>>2567863
The voltmeters that can measure high voltages are kind of pricey I think...

[Anonymous No.2567876]

What are some good resources for smps supply design?

I am trying to fix a bunch of chinese shit, but the IC's would take a half a year to get here. So I have to get equivalents. Really just PWM controllers, mosfets, feedback loops, and transformers.

>feedback loops go bananas with different mosfets of slight differences.
>unwanted oscillations
>ripple current out the ass
>voltage spikes and voltage drops below ground
>Isen being high reliant on the small +- 0.2 ohm resistor connected to source of mosfet.
>trying to get my oscilloscope to capture transient events such as start up and turn on
>RTV silicone everywhere
>specs on transformers are almost impossible since they are all custom made.
>traces are cheap and keep breaking, need to replace them
>DC offsets on isen and others
>probing with small micro hooks rated a 40 volts with heat shrink around it to compensate on tiny IC's
>probing optocoupler drastically changes the value
>sparks on optocoupler (very tiny)

[Anonymous No.2567881]

>>2567873
I made it so the voltage divider is like 5 resistors and its still giving me random numbers...

[Anonymous No.2567896]

>>2567881
iirc youre trying to measure the voltage output from a bug zapper? look mate, ill be blunt. given that you dont know what a scope of voltage divider is, you probably shouldnt be messing with anything that isnt below 5V. in any case, other anon is more correct, you need a "high voltage probe" on a scope. something that can handle like 10kV or more. youll also need to be recording on the scope because itll be difficult to homd the probs, press the switch and pause the scope sampling right on the pulse.

the reason youre seeing random numbers is because the multimeter can only measure DC or pure AC. its not designed to measure millisecond pulses. so what the mm does is it just averages it out over its sample time. which is roughly between 0.25 and 0.5 seconds. given that you were getting readings of 1000. that could mean it was a 1000V pulse over that sample time, or it could be a 10000V pulse over one tenth of the sample time. good luck figuring it out. solution?
>oscilloscope

[Anonymous No.2567915]

>>2567881
Stop trying to measure that fucking thing with out proper equipment. You are asking to have your shit destroyed. Sure 20 dollar meter here some components there but you need a scope to measure what it is you are actually attempting to do and given what you are doing you will blow the ass out of it. Especially if it is a digital scope. The old analog ones are a bit more robust and can handle a beating.

[Anonymous No.2567921]

>>2567896
I thought they were building some kind of jacobs ladder or something. If so voltage divider isnt going to work itll load down the circuit. But honestly I forget what it is they are trying to do besides mess with HV.

[Anonymous No.2567934]

How to figure out if you need to get an FPGA chip or you can just buy a faster MCU for a certain application?

[Anonymous No.2567936]

>>2567934
parallel vs serial processing

[Anonymous No.2567973]

>>2567876
There is this one jewish professor on youtube (Sam Ben Yaakov) that has lectures on everything you need. But if you want to become an expert there are no shortcuts. You basically need to learn linear circuits, semiconductors, control theory and mathematical modelling of switching systems. And then you forget about almost everything and start relying on SPICE modelling because algebra becomes way too complex.

[Anonymous No.2567999]

>>2567934
You don't know, and usually both will work, it's a question of which is more efficient and fast (and cheap). FPGA usually replaces something like a GPU or peripheral ASIC rather than a CPU.

[Anonymous No.2568011]

Here is the audio board I plan on making for the signal tracer probe I have made. What are your thoughts?

[Anonymous No.2568019]

>>2567718
> Iron too hot
Put an old light dimmer in series with it ro reduce the wattage

[Anonymous No.2568028]

>>2567804
Those zappers do charge up a capacitor with DC so you should be able to measure it with a multimeter. Your high-side resistor should be around 10MΩ, low-side maybe 100kΩ. They use maybe 10nF output capacitance, so that gives you 0.1s discharge time assuming no input power. Worst case you end up having to put the meter in MAX mode, and touching the divider+meter to the zapper only when it's fully charged. Best case the charging circuitry keeps pulsing at much quicker than 10Hz and you don't even notice a drop. The cap seems to take less than 0.1s to charge anyhow. If you're a divider with something like 1k then it will just load-down the circuit, and discharge it before you get a chance for the voltage to build up.

I'll try measuring mine when I finish work.

[Anonymous No.2568031]

>>2567876
> transformer specs
One of the hardest problems.
Everybody is afraid of those custom transformers (vs., say, capacitors) but you can do a lot just with a selection of toroid ferrites.
It will take a bit of time to wind your own toroids. The reason they use things like Si steel and e-cores are to save manufacturing time. Your transformer might actually be better than the original.
If you have kids or a wife and you need 1000 turns on a toroid ferrite, it’s a good time to introduce them to the hobby.

[Anonymous No.2568036]

>>2568031
What happens if it's a Mobius strip core and caduceus coil winding?

[Anonymous No.2568038]

>>2568011
> thoughts on signal tracer
Nice that you’re keeping all the copper
Looks very large for what it does
I’ve started using sot23 transistors (desoldered from a sony TV) they worked great.
I don’t make things with batteries, i just use external low voltage power supplies and split them, and maybe throw in a tiny vreg

[Anonymous No.2568043]

>>2568036
> alternate core forms
I’ve only played around with klein bottle ferrites — very low leakage — good for audiophiles.

[Anonymous No.2568047]

>>2568038
I want to do so but I dont have the parts or cash right now. A simple little battery pack will do for now I got room to redesign it later with SMD. I can do smaller than this but most of these parts are just shared between both devices so bought in bulk.

[Anonymous No.2568049]

>>2568038
I forgot to add the dimension picture I made.

[Anonymous No.2568051]

>>2567584
Ah of course, thank you. Im not the op but we covered parallel circuit equations literally the same day this guy posted, so now i feel like ive got a solid grasp on it.

[Anonymous No.2568063]

>>2568049
what kind of sudookoo is this?

[Anonymous No.2568065]

Is it worth trying to make a PCB at home nowadays if I never did it before?

[Anonymous No.2568071]

>>2568065
It's worth knowing how to do it, but it will cost more to /diy/. You're also limited to simple PCB designs (single or double sided, low speed, low frequency) and larger footprints. Depends on what you value.

[Anonymous No.2568072]

>>2568065
They've become so cheap to order online and get printed with slave labor in China, in the last decade it's never been worth it. Unless you just want to have fun and make something memorable ofc.

[Anonymous No.2568073]

>>2568063
>puzzles.ca
Canadian one, obviously.

[Anonymous No.2568074]

>>2568065
Sure, depends what you have on hand/access to already, and what your intentions are.
If you want to be able to pop out a simple 1-layer without too much fuss in an afternoon, absolutely.
Anything more, and I start to weigh how much effort it's going to be. I've done 2 layers at home with rivets, I don't care for it personally.
Ordering PCBs is so cheap anymore, speed is the main driver for me, it's not some huge savings or anything.

Personally, I'm happy to not be etching boards anymore. You still can, the bag setups are neat and much cleaner than tupperware containers of horror.
Chinky desktop mills good enough for PCBs are so cheap nowadays, but again it depends on your needs, it's easier to get fine traces and tighter tolerances if you're etching versus using a cheapshit mill.

You can also get all fancy about it, some folks pick up resin 3D printers and use them to expose photoresist, solder mask, and silkscreens on boards.
It's quick, versatile, you can get great detail out of it, and you use fewer consumables than most other etching methods.
I've done it, but only to have tried it, I only have one resin printer and it's for resin printing. Cool process though.

[Anonymous No.2568090]

I need a bench top power supply. I don't need megawatts of power. I'm just goofing around in my basement. Should I just get some 100 dolla 10 amp jobo off eBay or is there a recommended model ?

Example :
https://www.ebay.ca/itm/255647432590

[Anonymous No.2568096]

>>2568090
Wtf why they are so expensive? There's literally 500W PC power supplies for 25 bucks.

[Anonymous No.2568101]

>>2568090
That's way too expensive lol
If you're using regulators anyway, $10 picrel will work, you don't need the precision or those displays.
If not; https://www.adafruit.com/product/4880

[Anonymous No.2568150]

>>2568096
Doesn't have variable output.
>>2568101
Doesn't have current limiting.

[Anonymous No.2568153]

>>2568150
Use something like a ZK-4KX buck/boost module with a ATX PSU.

[Anonymous No.2568175]

>>2568150
>Doesn't have current limiting.
uhh, yes they do? It's just a snap or fuse instead of a dial.

[Anonymous No.2568178]

>>2568150
>Doesn't have variable output.
DC/DC power converter is about $3. It's the AC part that's hard


>Doesn't have current limiting.
yeah, it does, just maybe not as granular as you want.

[Anonymous No.2568181]

>>2567804
lol

[Anonymous No.2568197]

>>2568175
Do you seriously not know what current limiting is?

[Anonymous No.2568198]

>>2568011
Assuming you’re just using components you already have, it’s fine. Could make it smaller with vertical resistors. Consider making the ground full clearance larger to give your toner transfer less of a hard time.

>>2568065
If you want to make it into a hobby unto itself, then sure. Be that micro-routing or chemistry. I personally want to make my own minimum hassle multilayer board fab setup, which I might get around to if I crack the electroless silver plating for bias and through-holes. And perfect my ferric chloride regeneration electrolysis setup without making chlorine gas. And complete my Inkscape laser G-code script.

[Anonymous No.2568203]

>>2568197
it's V/R or P/V
you already said how much amps you want (~10). If there's much more than that it'll stop. You can even change the part that detects/fuses it, to decide how much. Or like this guy saying just do it externally:
>>2568153

[Anonymous No.2568210]

>>2568101
> sturdy PSU picture
I have similar, except it’s a rotary switch instead of a pot and it just uses, like, a 7805 reg for 5v etc… just the common voltages. I think they are rated for 1 A or so, which is fine for 99% of what I’ve needed to do.
You might want a ±15v supply for effing around with op amps and comparators.
3.3v was new to me (well, years ago) when some components started using that, but there is a reg for that.
I even see 1.1v stuff nowadays, but haven’t added that voltage to the switch yet. For 1.1v I think you’d need thick ass leads to avoid the voltage drop, no?

[Anonymous No.2568213]

>>2568090
I got this one off Aliexpress. I've load tested it and everything and it's solid. Very sleek and nice interface too.

[Anonymous No.2568215]

>>2568213
https://www.aliexpress.us/item/3256802964719977.html?

[Anonymous No.2568219]

>>2568215
>$60
Bruh

[Anonymous No.2568222]

>>2568219
it's a simple one time expense that is nice to have

[Anonymous No.2568236]

>>2568222
> just fukn buy it
Listen to this guy, he’s got a $30 can on Nu-Trol there.

[Anonymous No.2568244]

>>2568236
was only $20

[Anonymous No.2568245]

>>2568090
this isn't cheap (and you need to buy a separate power supply which could cost $60 or more on digikey or from Riden, and riden suggests you to use proper power supplies, like the one they offer or else you would damage the interface).
If you want buck and boost conversion for 50v 5a
DPH5005:
https://www.aliexpress.com/item/32840324731.html
There is also the DPS series, which is like the buck boost variant but a few dollars cheaper, or you can pick a much higher current.
This one doesn't have a separate board, which is nice for compactness (50v5a)
https://www.aliexpress.com/item/32596330856.html
if you want the cheapest option with an ugly display at 20v 2a (perfect for a laptop power adapter)
DP20V2A:
https://www.aliexpress.com/item/1437960167.html
If you want to most expensive option (buck only) for 60v 6a with proper buttons:
https://www.aliexpress.com/item/4000282551930.html
These are really expensive, but they are very modular which is nice.
I went with a really cheap boost converter for charging my ebike battery using laptop power supply I had hanging around instead (8.5V-48V but current depends on voltage difference, so 19v to 42v can only handle 1a with a heatsink without a fan):
https://www.aliexpress.com/item/32658959267.html
I kind of regret going with this because I was hoping to buy a 200w laptop power adapter for $15 since I see them all the time on my police auctions (20v 10a), but the heat was higher than I expected (It probably would work with 2a with a fan, but I really don't want a fan). But this supply was only $5 so I can't really be mad.

[Anonymous No.2568246]

>>2568197
This is posted here at LEAST once a day, anon. Resistance limits current w.r.t. voltage. If you don't understand that you probably shouldn't be using voltage at all.

[Anonymous No.2568255]

>>2568245
also the reason to use riden power supplies is because of accuracy, usually for testing equipment, people would tell you to to only use linear power supplies (they are $80+ used and the specs don't go as high, and they are heavier due to the big transformer).
But if you use the correct power supply, the ripple will be very small, and it would be comparable to a linear power supply (but you could just buy a linear power supply, just with less specs).
If accuracy doesn't matter, I guess you could buy anything (including the first switching power supply with a couple 1 star reviews you find for a good value).

[story time No.2568263]

So I bought one of these cheap backup cameras on ebay to use for a project not related to backing up vehicles. The video quality is trash but they have the selling points of being cheap and claiming to be weatherproof. Some similar cameras have little wire loops you can cut to toggle mirroring and the parking guide lines and I expected this one would too, but no dice. My first inclination was to shave down the part where the composite video and the power cables come together, where those wire loops usually come out. I thought this would just be wires soldered together but instead I found a little PCB with a voltage regulator and reverse polarity protection. Only 3 wires (12v, gnd, video) in and 3 wires (3.5v, gnd, video) out. I knocked one of the voltage regulator caps off while cutting off the rubber so I had to replace it with a new one.

[story time No.2568266]

At this point I realized that the camera itself was not potted as I expected, but unscrews with an O-ring. So I unscrewed it and found a little PCB with a bunch of passives and an AT24 EEPROM. But more interestingly there are 3 pads with labels somewhat nearby "MIR" "P/N" and "OSD". So I carefully soldered some wires to the little pads and tried connecting them to things while watching the video. "P/N" seemed to just garble the output, but connecting the "MIR" and "OSD" to power ground gave me the video I wanted without the parking lines and mirroring.

[story time No.2568268]

Next part was trying to connect those to ground in a way where I could still screw the back on. Getting a soldering iron to the ground wire coming in without breaking it would be tricky, so instead I looked at the AT24 datasheet and found that pin 4 was ground, so bent my wires and soldered to there. Closed it up, wrapped the regulator PCB in kapton tape (I don't have heat shrink big enough) and the job is complete. Thanks for reading my blog. Like, subscribe, and join my onlyfans if you want to support the channel.

[Anonymous No.2568284]

This is an ancient soviet photoresistor. I'd like to have a present day western photoresistor of similar aperture.

[Anonymous No.2568288]

AAAAA I got screwed with these stupid connectors again. This time I got non-insulated panel mounted BNC sockets. WTF Who the fuck uses the metal case as the return path? Holy shit. The case is supposed to be AC grounded for safety. What are these morons thinking? Now I need to come up with another hack and find some kind of stepped nylon washers.

[Anonymous No.2568295]

is it possible to use SMD components at home? what are the limitations of circuit boards in a diy sense? it's all very complicated. i know THT is the most common because it's all large enough for people to solder and prototype with it, but what happens when the design is finalized and ready to be miniaturized or just made into a more efficient package?

[Anonymous No.2568296]

>>2567804
>I still can't get a clear reading...

you're kinda hopeless.
there are 2 ways to make voltage divider.
#2 divides voltage by 50% (assuming input impedance of meter is 10M)
#3 divides voltage by 33%
#1 doesnt divide at all, and is useless.

from following your messy wiring, it seems you opted for #1.

[Anonymous No.2568297]

does anyone know what kind of bulb this is? its just has the marking 10V and H. it was from an old VU meter but its burned out.

[Anonymous No.2568298]

>>2568268
Good work faggot, what a pleasant adventure.

[Anonymous No.2568305]

>>2568295
yes. smd parts are actually more common and more available. contrary to popular belief, they are just as easy to work with compared to though holes. 0603 size components you can do easily, anything smaller might require a hot plate/oven and paste

[Anonymous No.2568309]

>>2568305
>just as easy
As a lab tech and TA for EE undergrads, I can tell you, this is only true for non-retarded non-cavemen, who understand the difference between holding and pointing and can reliably make their fingers do it

[Anonymous No.2568310]

>>2568288
>WTF Who the fuck uses the metal case as the return path?

everyone, it seems.
i checked all 3 of my scopes, and one function generator, and they all do it.

[Anonymous No.2568318]

>>2568263
>I bought one of these cheap backup cameras

those are so tiny i can fit them *inside* the spy hole on my front door.
this gives a very very much improved angle of view.
i just keep the fish-eye lens part glued to the outside so it looks like a normal spyhole, not a perv spyhole.

[Anonymous No.2568387]

>>2568203
I take that as a "no"

[Anonymous No.2568390]

>>2568309
> white cavemen fat sausage fingers
Most smd electronics is probably made and repaired by asian women with their tweezer-like fingers.

[Anonymous No.2568397]

[spoiler]>>2568305
>contrary to popular belief, they are just as easy to work with compared to though holes

They really aren't. They're more difficult to solder, very small packages are difficult to even manipulate (triply so if you have shaky hands), and you can't put them on a breadboard without breakouts, which complicates quick prototypes. And fine-pitch BGAs are just lmao in general. Literally the only advantage SMD parts have is situationally-easier routing, because the pads don't penetrate every layer on the board.

Don't get me wrong: Despite this, they're not that bad to work with, and most of the stuff I actually get around to making is heavily populated with SMD parts. But to say "they're just as easy to work with" is, at best, disingenuous. Surface mount technology was developed with automation and high-density electronics in mind, not ease of use by human hands.

>>2568295
>what are the limitations of circuit boards in a diy sense?

If you're not the one making them, none. The fab house making them will do pretty much whatever you want, as long as you're paying them enough. There isn't anything different as far as designing them, you're just going to want some specific equipment when populating them. If you are making them, then...pretty much whatever limitations your process has when making THT parts.

[Anonymous No.2568401]

>>2568255
Switching PSU + linear postregulator is a pretty easy way of getting low ripple and high efficiency. Be that postregulator just a darlington/sziklai capacitance multiplier, or a dedicated op-amp feedback loop.

>>2568268
Great work anon. This kind of dumb hardware hacking is fun.

>>2568284
Too bad. Chuck a chinese CdS photocell in a plastic housing.

>>2568295
They're definitely doable. If you stick to SOICs and 1206/0805 then it's easy so long as you have decent tweezers. Going to 0603 and SSOP you may want to invest in magnification, anything smaller definitely so. Leadless packages can be a pain to hand-solder without fancy footprints. If you plan on using particualry small or leadless components (or LGA/BGA/etc. meme footprints) I'd highly recommend making a reflow oven or reflow hotplate.

>>2568297
Possibly a phosphor coated fluorescent (VFDs only need 10-20V to light up so it's technically possible) but chances are it's an incandescent. That kind of packaging looks pretty similar to some automotive/RV light bulbs, might get lucky there.

>>2568387
"current limiting" does not imply "vairable constant-current", though it does hint at it in these circles. It could also refer to an overcurrent latch/crowbar circuit.

[Anonymous No.2568404]

>>2568401
>"current limiting" does not imply "vairable constant-current", though it does hint at it in these circles. It could also refer to an overcurrent latch/crowbar circuit.
Ding ding ding

All of the power supplies I've suggested are current limited, as you requested.
>>2568101
They aren't constant current, because you literally never mentioned that. CC supplies also pretty dangerous for noobs, like those who would conflate "limited" with "controlled".

[Anonymous No.2568407]

>>2568404
Sorry forgot to link to the post:
>>2568387
unironically "no u"

[Anonymous No.2568447]

>work at local jaycar
>digging through the obsolete freetronics bin out back
>bunch of old modules
>atmega32u4 board with full gpio and icsp breakouts like a pro micro, but with a usb connector built in to the pcb like a digispark for about $7
>usbasp with 3.3v/5v switch and a "power output enable" jumper for like $4
>poe step-down board that can handle up to 48v input and will output 7.5v intended for an arduino 5v regulator, cheap
>mpu9150 imu breakout board for $14, check original price on website and it's $95 lmao
if you're in aus/nz i recommend checking out the old freetronics range on the website or an old catalog, there's some interesting stuff there. think i even remember seeing some sort of fpga on a video conversion dev-board.

[Anonymous No.2568451]

>>2568447
every time ive gone to jaycar their shits been fuck huge expensive (or expensive knock off products). does the cheap stuff show up on the website or is it in store only?
Also fuck jaycar and fuck altronics

[Anonymous No.2568462]

Is there any reason to not replace a 1uF aluminium cap with a 1uF mlcc?
I'm doing some of the circuits from music from outer space and Ray Wilson uses 1uF aluminiums and non-polarised aluminiums which are fairly difficult to find (especially if I want to do smd).
I suspect that it's just because good quality ceramics didn't go up to 1uF when he designed these circuits over ten years ago.
I can get 1uF in x7r and then don't have to worry about polarity.

[Anonymous No.2568481]

Coming from /rcg, we were talking about tethered drones there.

The problem is to calculate the minimum wire gauge to supply the drone with necessary current. All on the internet available wire calculators are complete bullshit, they give results for a perfect connection, while in reality you power your shed 100ft away with a simple small gauge extension cord no problem.

Voltage 24V
Current 25A
Distance 150ft (50m)
I need THE MINIMUM DIAMETER BEFORE IT FUCKING BURNS
Thanks

[Anonymous No.2568551]

>>2565489
I am fucking SICK of not knowing how inductors work!
Where can I learn more about them? At least enough to design a transformer for a flyback circuit or something similar

I wound two copper wires on a torroid core and programmed a pi pico to create 50KHz 1% duty cycle controlling a 2n2222 and nothing happened! 0V on secondary! I am FUCKING SICK OF THIS deception

[Anonymous No.2568554]

>>2565564
Shut it down! It's not... it's not shutting down!

[Anonymous No.2568565]

>>2568551
Just ponder the pic related. Then you need to understand that inductance is a measure of voltage is induced for a given amount of change of current or alternatively how much magnetic flux is produced for a given amount of current. For transformers you can then create analogous magnetic "circuits" where volts == ampere turns, current == flux and resistance == reluctance.
https://en.wikipedia.org/wiki/Magnetic_circuit

[Anonymous No.2568581]

>>2568310
Why?! How? Any device in a metal box is supposed to be ac grounded for safety. And scopes are sure grounded. You can't connect your DC ground from the internal circuitry to the AC ground directly, can you?

[Anonymous No.2568583]

>>2568565
So you are flexing on him and giving him the Maxwell equations as a 101 explanation of inductance? That's cruel.

[Anonymous No.2568586]

Im looking for boost converters with higher output voltage than usual 60V, but find nothing. Why? It's enough for me to have 200W, but even though there's none.

[Anonymous No.2568594]

>>2568581
>You can't connect your DC ground from the internal circuitry to the AC ground directly, can you?

you can and you should.
like all professional lab equipment has done since JFK.

[Anonymous No.2568604]

>>2568581
>AC ground
be careful not to conflate the AC neutral return line, with the low-impedance 'Earth' sink.

[Anonymous No.2568616]

Any ideas for smallest ways to measure the angle of a joint? Putting together a concept for a miniature robot arm and I want some sort of closed loop feedback for the joint positions.

All encoders seem to large, I’m worried about the force requirements and accuracy of small potentiometers. There’s some small AMR sensors that look promising but also the documentation for those is kinda lacking and it seems nobody in the hobby scene is really using them…

[Anonymous No.2568617]

>>2568583
If you ignore funny mathematical squiggly lines it's not that hard to understand. What's hard is solving those equations for non-elementary problems, but that's what we have FTDT and FEM for. Once you have vague understanding of how, when and why magnetic fields are formed then you can start playing with something like femm and simulate transformers to see where gaps exist in your understanding.

[Anonymous No.2568619]

>>2568404
>CC supplies also pretty dangerous for noobs
OK, now I'm intrigued. In what scenarios is a CC supply more dangerous then without?

[Anonymous No.2568620]

>>2568604
This.

[Anonymous No.2568621]

>>2568619
Hooking up a supply in CC mode to most widgets will fry them. They expect small, constant voltage and the supply will ramp up high trying to get the specified current. It's the same issue as charging up an inductor and then moving/draining it.

Starting a supply up in CC mode with no load (or extreme load) is also a big no-no. Current mode is just a very rare use case for testing motors and individual BJTs and stuff

[Anonymous No.2568622]

>>2565533
>2n7000
This MOSFET can only handle around 200mA, it's minimum drain-source resistance is 5ohms so even at 100mA it would have 0.5V voltage drop across it! I would recommend using a BUZ11 since the Vgs of it is 3V, so by 5V you're already getting it into saturation (very low drain-source voltage drop, thus very little power lost on the transistor). You can also use a BD139 or BD140, although you will have to calculate the base resistor such that you will get the transistor into saturation.
For a BD139, the hfe is 40 at 0,15A collector current (it decreases as the collector current increases). Assuming you connect the base resistor straight to 5V and you need to let trough atleast 100mA trough the collector, you would need a base current of atleast 100mA/40, so atleast a base current of 2,5mA, The base-emitter junction is like a normal rectifier diode so to get 2,5mA trough it you would need a resistor that is equal to 5V-0,7V/2,5mA, which would be 1,72kohms. I'd put in a 1kohm resistor, which would mean the BD139 would only let trough 172mA trough it. For getting the BD139 into saturation you'd have to bias it in such a way that the base current times the hfe results in more current than what the load will actually allow.

[Anonymous No.2568623]

>>2568621
So if I set the supply to (say) 5V 100 mA it's going to go way over 100 mA and fry my widgets?

[Anonymous No.2568624]

>>2568623
No. Set like that, it's either putting out 5V and limited to 100mA, or putting out 100mA and limited to 5V. The CC/CV switch decides which is fixed and which is not.

[Anonymous No.2568625]

>>2568622
You can also make a constant current source for each heating pad you have, which will make sure you get the same current trough all of them, although this requires more components.

[Anonymous No.2568626]

>>2568624
>putting out 100mA and limited to 5V.
this won't fry anything (probably) at 5V, but it also means your thing won't work.

[Anonymous No.2568631]

>>2568604
I remember that video but grounding has always confused me.
So what happens if hot is shorted to the metal case? Wouldn't that kill all the internal circuitry before tripping the circuit breaker? You are essentially connecting hot to the DC ground of low voltage circuitry. There will be a huge instantaneous surge of energy.
Also, wouldn't connecting earth and internal ground cause ground loops ?
What's wrong with #2?

[Anonymous No.2568636]

>>2568631
>So what happens if hot is shorted to the metal case?
The resistance on the Earth wire is extremely low, ideally almost zero. That charge would prefer to take the path to Earth, than go through your circuit. More importantly, it wouldn't go through YOU if you had a hand on the case .

[Anonymous No.2568637]

>>2568624
>>2568626
Now I'm even more confused. 4chan is a bad place to explain this. You have a link to a good explanation?

[Anonymous No.2568638]

>>2568637
Sorry. It's the difference between a capacitor discharging and an inductor. I don't really know a more natural way to explain it.

[Anonymous No.2568647]

>>2568636
>More importantly, it wouldn't go through YOU if you had a hand on the case
Yes I get why earthing the chassis is important for safety. I just don't understand why the earth and the internal ground should be connected together. I know some bench power supplies gives you an option of leaving the internal ground floating or connecting it to earth, typically through the green binding post.

[Anonymous No.2568648]

>>2568647
Typically for noise/isolation. It prevents EMF from kicking your floating ground up or down, or some loose wire/static/etc from holding it way off Earth where it might short anyway

[Anonymous No.2568650]

>>2568648
You also don't have to connect them directly like that. Some people use a ferrite core, or zero ohm resistor, or even a zener diode

[Anonymous No.2568652]

>>2568650
I've also seen examples with a huge resistor between the two grounds, similar to how transformer windings are simulated in LTSpice. So confusing.

[Anonymous No.2568653]

Can you stop for a second and tell me how to convert 24V DC into around 200V DC? I'd buy a converter or try to make one, just give me something.

[Anonymous No.2568683]

>>2568653
https://en.wikipedia.org/wiki/Boost_converter
That's a big boost though! You will draw a shitload of current on the 24V.

[Anonymous No.2568691]

>>2568653
If you don't want much current, go with a charge pump aka voltage multiplier
If you decide to go with a boost converter as >>2568683 anon recommends, you will need a very powerful 24V source.

I suggest you go with a flyback transformer. High power and not unreasonable current draw

[Anonymous No.2568695]

>>2568653
>convert 24V DC into around 200V DC?

super easy.
get one of these things and use some diodes and a cap to rectify AC to DC.
120Vac (rms) will give you about 170Vdc (peak).

[Anonymous No.2568702]

>>2568691
All of these will draw ~ the same current with the same load. Power in is still power out. Switching regulators are like 99% efficient.

[Anonymous No.2568710]

>>2568702
Charge pump would be the most efficient, followed by flyback and then followed by boost
The current draw would depend on the load.

[Anonymous No.2568724]

>>2568683
>>2568691
>>2568695
>>2568702
Thanks, I'll probably solve the problem differently by connecting 40x 18650 3.7V batteries in series to get 148V which should work as well lmao.

Now the other problem is to make it the other way around. These 148V DC back to 24V DC, the power draw will be around 200W constantly. Something like step down converter?

[Anonymous No.2568731]

>>2568724
why the fuck are you using so much juice? there's got to be something a bit better than converting back and forth. what are you working on?

[Anonymous No.2568734]

>>2568731
> there's got to be something a bit better than converting back and forth
I don't think so.
> what are you working on?
It's here >>2568481
I figured out that nobody does pull huge wire up in the sky because they use current converters. So stepping up the juice is because of wire gauge, it must be small otherwise the drone wont fly.

Check this wire gauge https://youtu.be/Qk7v6k_aDD4
The drone draws many amps easily though.

[Anonymous No.2568739]

>>2568734
what kind of drone are you making that will consistently draw 200v? that's a massive amount of power. do you even have a battery setup in mind that could keep something like that afloat? or are you going to have it be a gas generator? because at this point, it sounds like something that could easily warrant a gas generator

[Anonymous No.2568742]

>>2568739
I think he's calculating voltage drop along 6 gorillion feet of wire.

[Anonymous No.2568759]

>>2568739
>what kind of drone are you making that will consistently draw 200v?
I think I explained it poorly. Here is the professional infographic I made, this might be better.

[Anonymous No.2568760]

>>2568451
Yeah the obsolete stuff is heavily discounted. Some is still on the shop floor, but most is out back so you have to ask the staff for it. If they can't find it or don't have it, they may still have it in other branches and can order it in for you. Yes they will courier in a 50c part at no extra cost to you.

>>2568462
MLCCs and electrolytic caps each have their upsides and downsides. Modern high-capacity ceramics like that often suffer from voltage-dependant-capacitance, so I wouldn't use them for anything other than PSU ripple rejection. In your case high fidelity probably isn't hugely important so I'd probably give it a shot, but going for a film cap of some sort is probably a better bet. That or picking a ceramic dielectric without significant voltage-dependance.

>>2568616
Optical or magnetic is the way to go. Look for those magnetic rings with a large number of pole-pairs to connect to the output shaft. Then you just hold a hall-sensor nearby.

>>2568626
Mate lots of 5V circuits will run just fine at 100mA. You just size the current limit for the maximum load you're expecting.

>>2568734
A better idea is to just send 200V (or maybe even like 1kV) AC through the wires, with simple AC transformers at either end. Use a shitty ZVS inverter to feed the first transformer, and a full-bridge rectifier to make it DC after the second transformer. If you pick a high frequency then you can make the transformers a lot lighter than what a 600W transformer would normally weigh. Take a look at the meme metal toroid Marco Reps used in a couple of his latest videos.

Just having a 600W 240VAC inverter at the bottom side and a 600W 24V SMPS at the top side is also acceptable, and may well be lighter, though the cable would be heavier than if you were going to 1kV.

>>2568759
enjoy the 46S BMS lmao

[Anonymous No.2568767]

>>2568759
Balloons are all the rage these days. Make a RC zeppelin and tether it to your house.

[Anonymous No.2568771]

>>2568760
>size the current limit for the maximum load
soo...not a constant-current with a voltage limit, but constant voltage with a current cap, then? (:

[Anonymous No.2568779]

>>2568759
https://en.wikipedia.org/wiki/Atmospheric_electricity
>Near the surface of the Earth, the magnitude of the field is on average around 100 V/m
Electric kite?

[Anonymous No.2568780]

>>2568760
>5V circuits will run just fine at 100mA.
No, "Mate," you read that reply chain completely wrong. In a current source, that'd either droop voltage like a dying battery, or overvolt the 5V, to maintain 100mA.

>>2568760
>200V (or maybe even like 1kV) AC through the wires, with simple AC transformers at either end
I don't think a drone could lift an HV AC transformer, even a 120V one.

[Anonymous No.2568783]

>>2568760
>A better idea is to just send 200V (or maybe even like 1kV) AC through the wires
high voltage transmission only matters for DC. Google "HVDC." It's not really used in practice.

[Anonymous No.2568789]

>>2568760
>>2568780
>>2568783
Ok, I updated my amazing infographic. But you gotta choose the best solution, please.

[Anonymous No.2568801]

I need a smaller motor that:

1. can spin in both directions
2. the speed/power can be roughly controlled
3. Can be easily controlled with an Arduino. I can buy any drivers necessary

[Anonymous No.2568807]

Running a 240 to my garage. I have a drop ceiling in my basement so access is easy.

The main trunk of the HVAC system runs parallel to the main beam spanning the length of the house. Any reason not to run the romex along the main beam, in cable staples, and between the beam and hvac trunk? I can have it do one bend, go over the top of the main beam, and then directly down a floor joist straight to the panel. I don't think there are any code violations here with that plan. At no point will the romex dangle under any joists.

The alternative is drilling approximately six million holes in joists as all the other holes are full, and they will be in locations near water pipes and hvac ducts. It only adds about 12 feet to the run to take the lazy way out.

[Anonymous No.2568818]

>>2568771
>>2568780
He said
>So if I set the supply to (say) 5V 100 mA
Presumably that means to set the voltage limit to 5V, and the current limit to 100mA, of a CC/CV variable PSU. One isn't a limit and the other a cap, they're two identical feedback loops combined into one via diodes. The output voltage will be no higher than 5V, and the output current will be no higher than 100mA. While the current is less than 100mA, the output will be 5V exactly, and while the voltage is less than 5V the current will be 100mA exactly. I don't see where the implied lack of symmetry is coming from.

>>2568780
>I don't think a drone could lift an HV AC transformer, even a 120V one.
Thats why you use a much higher frequency sine than 50/60Hz. Like 100kHz. Can make the transformer orders of magnitude lighter. Using mumetal or similar high-perm core materials means you can get away with less turns for a given impedance.

>>2568783
>high voltage transmission only matters for DC
I don't understand what you're implying. The reason to use AC is you can pick arbitrarily high voltages and just rely on transformers for voltage conversion. If you go above ~600V with DC, then you end up having to use increasingly more specialised semiconductors to switch that in a step-down converter.
Regardless of whether its AC or DC, a higher voltage means a lower current for the same desired power, and so you can use a thinner wire. The point is to minimise the weight of the step-down converter / transformer AND the weight of the wire.

[Anonymous No.2568820]

>>2568724
Or you could make a step-up converter, either with a transformer or without one. 40 18650's is pretty hard to balance and it's also gonna take up a lot of space

[Anonymous No.2568825]

>>2568481
2/0 AWG (67.4mm squared) copper wire, this will mean only around a 10W power loss across the wire, so you'll get around 23,5V by the end of the cable if you draw 25A.

[Anonymous No.2568831]

>>2568551
The inductor still behaves like a voltage divider with the source impedence. If Rs is 200ohm and X_L is 10j ohm, you're only gonna see 5% of your input signal over the primary.

Same applies to your secondary. This is why high permeability toroids are usually used for transformers.

[Anonymous No.2568836]

>>2568825
>67.4mm squared
Thanks but no.

>>2568820
That's what I'm going to do. Either var. 3 or 4.

>>2568818
> Thats why you use a much higher frequency sine than 50/60Hz. Like 100kHz. Can make the transformer orders of magnitude lighter. Using mumetal or similar high-perm core materials means you can get away with less turns for a given impedance.
Look at what I've found on picrel:
Power: 1000W
Input: 12VDC
Output: 220-420VAC
Output Frequency: 20kHz
Price: $30

Now what's left is the converter from high voltage high frequency current into 24VDC.

> Regardless of whether its AC or DC, a higher voltage means a lower current for the same desired power, and so you can use a thinner wire. The point is to minimise the weight of the step-down converter / transformer AND the weight of the wire.
That's correct, I need to minimize weight.. More weight > more powerful motors > more power draw > more wire thickness > more weight.

[Anonymous No.2568840]

>>2568836
>Now what's left is the converter from high voltage high frequency current into 24VDC
Buy the same transformer that's on the PCB there (or a lighter one with the same specs), then put a rectifier and caps after it.

[Anonymous No.2568844]

>>2568840
If it's so easy why these need to be so big and heavy? 1kW from here is 1.7kg.

[Anonymous No.2568848]

>>2568844
Heavy transformers are a lot cheaper than high-spec transformers. Also maybe it's the big filter caps. As I've been saying, you should go for high-spec high-permeability magnetic cores because you need a lot less copper on them, while cores with high capacity for magnetic fields are better for being smaller before saturating. I'd consider browsing digi-key for toroids and making a list of which ones can handle the most amp-turns per kg, and which have the highest permeability.

[Anonymous No.2568850]

>>2568848
Oh right, those are for 50/60Hz, comparing to the small one for 20kHz. Probably here lies the difference.

[Anonymous No.2568853]

>>2568850
Nah those ones you posted are still high-frequency converters. They rectify first and then switch through the transformer at high frequencies. An actual 50/60Hz transformer for that kind of power will easily weigh twice that of an entire switching PSU.

[Anonymous No.2568858]

>>2568818
No, you are not getting this. A voltage source is fundamentally different from a current source. If OP's widget drew more than 100ma on a 5v source that would be fine. If it drew more than 5v on a 100ma source, it would break. You can't even simulate them in a circuit the same way; one is series and the other parallel.
see:
>>2568638
Most things expect power like a capacitor in parallel. That's what batteries and AC/DC adapters and consumer power supplies do. A current source is instead like an inductor in series.

[Anonymous No.2568859]

>>2568858
Point being, the response to changing load is completely different. One "tries" to maintain voltage and the other "tries" to maintain current. The other number for each one is just like, a fuse that will stop it from going over, a limit. Not a set point.

[Anonymous No.2568866]

>>2568853
I don't understand anything anymore... It says 50Hz input on some and none on others.

[Anonymous No.2568876]

>>2568858
>A voltage source
We're not talking about some ideal thevenin bullshit. We're talking about an actual physical benchtop power supply, as first posted at the start of this chain of idiocy here: >>2568090
First this anon wanted to buy a conventional CC/CV PSU. Then another anon or two said something along the lines of "hey just use this PSU that doesn't have current adjustment but at least it has a fuse lmao", and then they got into an argument about what "current limiting" means. Then somehow maybe it turned into a "constant voltage" OR "constant current" argument, which is completely removed from the aim of the initial post.

These benchtop variable CC/CV power supplies have both a current and a voltage feedback loop, but the diodes connecting them to the central switching/linear feedback circuit mean that at any one time only one of the two feedback loops is going to be connected. Only the feedback loop that is forcing a lower output voltage will be active, the other will be open-loop.
Ultimately, if you want to be pedantic, it's just a variable voltage power supply, but with a current sensor in series with the load, and a seperate feedback loop that reduces the voltage of this power supply if the current gets too high. If you want me to put a useful label on that, I'd say "CC/CV" or "variable voltage and current", like everyone else does.

>>2568866
That's the input frequency, the diodes and filters and such can only handle so high a frequency. Also there might be some sort of power-factor correction in there. It gets rectified after the input anyhow. Also stop looking at aliexpress.

[Anonymous No.2568898]

>>2568622
What's this software?

[Anonymous No.2568913]

>>2565489
Circuit JS https://www.falstad.com/circuit/circuitjs.html

[Anonymous No.2568914]

>>2568913
I thought this was in the OP?
I'm a crackhead I don't remember.

[Anonymous No.2568954]

There's something I don't understand.
Let's say my drone consumes 8A at 24V. That means the load resistance shall be R = V/I = 24V/8A = 3 Ohm, that I applied in simulator.

Via input wire comes high frequency AC current (380V, 20kHz), which I transform and rectify. My problem is, I've tried all transformation ratios, and best I'm being able to register ia 13.7V with 4.6A. Why it's like that?

[Anonymous No.2568965]

Do you prefer binding posts aligned horizontally or vertically? Do you care? Most power supplies have them horizontally oriented but I've seen some that are vertical.

[Anonymous No.2568966]

>>2568954
ignoring the inanity of the rest of the post, if you want to increase the voltage across load you have to increase the number of turns in the secondary
hth.

[Anonymous No.2568968]

>>2568954
Why 20 Khz? You also need to add some capacitors. You are looking at peak values but I am assuming you need DC?

[Anonymous No.2568972]

>>2568624
My bench supply would put out 5v 0A or 100mA 0v. If the load is between 50 ohm and 0 ohm it will put out 100mA at whatever voltage that works out to. Are you saying your supply will just blindly put out a gorrillion volts regardless of the voltage setting? That sounds retarded and useless. I did have that happen once when the kelvin clip shunt came loose, but that's a different problem.

[Anonymous No.2568981]

>>2568954
If you run 20khz@2A up a wire to your drone, a squad of boomers will descend upon you and sacrifice you to the HAM gods for infringing on their VLF spectrum

[Anonymous No.2569003]

It seems I did everything correctly, but my voltage and current keep dropping no matter what values I use on transformer and capacitor. Simulation error? Don't go hard on me, it's the first time ever I build a circuit and simulated it...

>>2568968
> Why 20 Khz?
This is why >>2568836, thats what the inverter produces.

>>2568981
Too low for them... Although 50m wire will be a nice resonator...

[Anonymous No.2569010]

>>2569003

HAHAHA.
the diodes go on the secondary, not the primary.

[Anonymous No.2569012]

>>2569003
>>2569010

and the cap needs to be, like 10,000uF.

[Anonymous No.2569020]

It was probably the simulation error, I changed the time step to smaller one and the voltage became stable.

>>2569010
> the diodes go on the secondary, not the primary
I did it like that here >>2568954 and it was worse in my particular case, I don't know the reason, but that's what it is with high frequency AC.

>>2569012
It doesnt change much though, just the time when oscillations become stable.

[Anonymous No.2569030]

>>2569020
>I did it like that here

and you need to do it again.
you're trying to get a DC voltage so you need diodes and a cap on secondary to accomplish that.
if you put the scope on the load you're gonna see some freaky waveform instead of a straight-line DC voltage.

since transformers are AC devices, they should ideally receive a pure AC signal and will output a pure AC signal.
so, no diodes should be present until all the waves have completely exited the transformer, without any perverted diddling.

[Anonymous No.2569032]

>>2568972
U still conflate a cap/limit with a set point. See you conveniently left that part unaddressed. >>2568859

I'd not take advice from this anon about high voltage lmao..

[Anonymous No.2569036]

>>2569010
nope... a rectified half wave will charge a xformer just fine, just try scoping the current.. only DC or a very low f wont induce a field
diodes on both is just fine

[Anonymous No.2569050]

I will try splice tomorrow, fuck this shit, it seems the the numerical integration solution is unstable and I get tenfold differences in voltage just by changing the time steps by a nanosecond. It's 100% a numerical error.

[Anonymous No.2569166]

How am I supposed to know what transformer to use if the difference in output voltage between simulation softwares is at least eight times?

[Anonymous No.2569171]

>>2569166
How many volts output do you need?

[Anonymous No.2569173]

sorry for the basic question. I have an old stereo amp which when powering on the relay does not click on with it. So all the lights work but sound does not. I was told to check the output transistors. Are those the same as the power transistors here on the schematic? these are both TO-3 large germanium transistors.

[Anonymous No.2569174]

>>2569171
24V
If you going to suggest the number of windings, please include also the inductance etc.

[Anonymous No.2569177]

>>2569173
>old stereo amp
>relay does not click on
>all the lights work but sound does not
Probe for voltage at the relay. If you get a good reading, jumper the high side of the relay to test.

[Anonymous No.2569185]

>>2569173
>relay does not click on
>was told to check the output transistors

there's often a speaker relay that clicks on a few seconds after power-on to give all the caps time to charge up, to avoid a loud thump sound.
until the relay clicks, the speakers are isolated, so you wont get any sound out of it.
except maybe at the headphone jack.
so, that has to be addressed first, before you go after the power transistors.
a gentle tap with a screwdriver handle might be all it needs to help it turn on.

[Anonymous No.2569192]

>>2569177
>>2569185
headphones in the front do not have any sound either. VU meters also do not move despite any input audio.
getting to the relay is tricky because the main transistors are screwed to the heatsink which in turn the leads are soldered to the boards so I'd have to desolder and unscrew two transistors to pull the board out, there might be enough space to slip a MM probe in there.

[Anonymous No.2569197]

>>2569192
You could try injecting audio after the relay to test the power amp and headphone jack.

[Anonymous No.2569198]

>>2569192
>getting to the relay is tricky

you can check for sound before the relays.
hook up a speaker in series with a big cap and touch it to emitter of Q8 or Q9.
other side to ground on speaker terminals.
if no sound, then trace backwards along the circuit using some amplified computer speakers as a probe.

[Anonymous No.2569201]

>>2569192
Check the input jack solder joints to rule them out.

[Anonymous No.2569204]

>>2568898
circuitjs, it's FOSS so you can even make your own components. I highly recommend it, it has no software limitations and the only limit on what you can do on it is your PC. It runs on Linux, Windows and I think also MacOS. It's got everything analogical and almost everything digital, for the digital stuff you can make subassemblies and name them.

[Anonymous No.2569206]

>>2569020
>It doesnt change much though
It changes how smooth your DC output is, if it has a lot of ripple, digital stuff will really not like it. And the analogical stuff will also not like it but won't be as much of a problem.

[Anonymous No.2569207]

>>2569204
I used it here >>2569166 and it shows voltage eight timea different comparing to spice. Why?

[Anonymous No.2569215]

>>2569207
>Why?

ltspice is a respected tool used by engineers worldwide.
circuitjs is a toy posing as a simulator.

[Anonymous No.2569219]

>>2569207
Are you sure you didn't mess up something with the transformer?

[Anonymous No.2569222]

>>2569219
No. I can share the schematics file if you would like to help.

>>2569215
It's also more complicated, maybe youtube tutorial I was following did it wrong and I copied the mistake?

[Anonymous No.2569227]

>>2569222
>I can share the schematics file

shoulda done that in the first place.
cant troubleshoot anything if you cant look under the hood.

[Anonymous No.2569229]

>>2569166
where are reference points in that circuitjs shit?
Transformer turns or inductances?
Have you measured primary voltage, current, secondary voltage current ?
What is magnetic coupling ? What are transformer windings resistance?

>>2569222
>youtube tutorial
>trusting indians
that worked well for boeing

[Anonymous No.2569236]

>>2569227
https://dropmefiles.com/4UAGO

>>2569229
I dont think I can learn the whole college progam so fast... Transformer settings here on screen.

[Anonymous No.2569250]

>>2569236

so, significant diff in input voltages: 380Vac (rms) on ltspice, but 220Vac (rms) on circuitjs.
also, if you wanted to get 24Vac on secondary from 220Vac, you'd need a turns ratio of 9.16, but you have it at 62.

for circuitjs, you should copy/paste the URL if you're doing it online.
something like this: https://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWK0wIBxgCwGYBsl8FcB2LHEATkhCXIQFMBaMMAKADdxNNxjcueAJiJRwIfOAqjqMBKwAmIQZmpgJ2QaomCQ8+gDMAhgFcANgBcFIDaoo7lt+7oMmLrAOYClIskuI6ZVgB3LzA+UIlIYIjqB3BI6Li1WJVJANZNKRtvfmywO2lYSAgwNGhMYmLBbEgKNEw0PEg0UTZM63qlZo6hf0K4ErLMXHrh3ARIGu5BAPAPa00chdi+wM9sTsE+jaE0FsCQvIKGxyhona6Wi+Szw86bvIS7nhuT+MCAJxBuFq2dH8uohmrC+2AQOjBEPBflmwMO0L+1mh+XSIQBmhaAJuUXW0MhSIhI2k83RfXRe2JeExaC01EwFH42LOVO+NLS3wZ7MCAHsuOIeHTalJFjB4LU+ERhEC+dhWEA

[Anonymous No.2569258]

>>2569250
Why do you think it's 220? It's 380 just like in LTspice.

https://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWK0wIBxgCwGYBsl8FcB2LHEATkhCXIQFMBaMMAKADdxNNxjcueAJiJRwIfOAqjqMBKwAmIQZmpgJ2QaomCQ8+gDMAhgFcANgBcFIDaoo7lt+7oMmLrAOYClIskuI6ZVgB3LzA+UIlIYIjqB3BI6Li1WJVJANZNKRtvfmywO2lYSAgwNGhMYmLBbEgKNEw0PEg0UTZM63qlZo6hf0K4ErLMXHrh3ARIGu5BAPAPa00chdi+wM9sTsE+jaE0FsCQvIKGxyhona6Wi+Szw86bvIS7nhuT+MCAJxBuFq2dH8uohmrC+2AQOjBEPBflmwMO0L+1mh+XSIQBmhaAJuUXW0MhSIhI2k83RfXRe2JeExaC01EwFH42LOVO+NLS3wZ7MCAHsuOIeHTalJFjB4LU+ERhEC+dhWEA

[Anonymous No.2569259]

>>2569250

oh, just realized ltspice prob uses peak voltage not rms.
but 220V rms would be 308V peak, not 380V

[Anonymous No.2569261]

>>2569258
>Why do you think it's 220?

says so in >>2569236
Vd1 = 223
Vd2 = 5
tho, those could be instantaneous readings.

[Anonymous No.2569263]

>>2569258

and that's the URL for my circuit.
where's yours?

[Anonymous No.2569268]

>>2569263
I fucked it up, here https://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3EBsZpgJwFY0A4As-1s0AmYjEXcqyEDAUwFowwAoANxAHYBmRW47F14hegmhGLwa3bDTlRoGFgBUhfDAJBp8IxGIoLIYZMTSRupDLMSVjIBjHhhKiRNs6ROaMJAGdchubE+Dz+2GAanJxYfDBo8SwAJlqSFLiCaHoUcCDEIIl0AGYAhgCuADYALklaWbg5Pnb4gnkFJRXVySQ0zbWCuJm5+UVlVTWZ-YONfL2tIx0sAO59uhl1OZBLKwN8E-xiW3uiWjrHm8t7Ghk6V1AskmjgkLJpgj4vGFlysBDc0LjOTJkQHYUycTSOIzgFgAJ3Axh66XhiBon303EOqV63VoXy201eTxevXOKVRWXe5IOy0phOYKMJpNpaORVLuAHt4SAbFBsvFaOBoLEhswRCwgA

>>2569261
I guess so, because it's transformer, not source.

[Anonymous No.2569281]

>>2569268

to get proper results
- drop the Henrys of the transformer by about 10x.
- drop frequency by like 300

[Anonymous No.2569283]

>>2569185
i took the casing off the relay to do a gently cleaning and loosening just in case it was stuck (i got this unit on the curb in the snow a few weeks ago)
when i went to power it up after the 4A power fuse blew but i heard a little click before it happened.
I ordered some new 4a fuses but i wont be able to do anything until tomorrow.

[Anonymous No.2569285]

>>2569281
Unfortunately I can't change the frequency.

[Anonymous No.2569294]

>>2569283
There's a short in the power section that needs to be addressed before you replace the fuse.

[Anonymous No.2569297]

>>2569285
>Unfortunately I can't change the frequency.

double click source and enter new values.

[Anonymous No.2569300]

>>2569285
Then lower inductance even more
If you see simulation and primary current graph, you'll see it pretty much turns into DC current and at that point you significantly fucked up design as it's less of power transfer and more of a heater

[Anonymous No.2569303]

>>2569300
What's the physical meaning of inductance in a transformer? Like a wire thickness in the windind or something?

[Anonymous No.2569304]

>>2569285
>>2569281

to be clear, i meant drop either the Henrys *or* the frequency.
dont have to do both.

[Anonymous No.2569307]

>>2569294
A short which didnt exist until i started looking around the power components and removing boards. I probably fucked up somewhere so i'll check all the connections again

[Anonymous No.2569311]

>>2569303
The primary coil is inductively coupled to the secondary coil through the core they both share.

[Anonymous No.2569320]

>>2569307
>fucked up somewhere

you're gonna end up blowing a lot of fuses until you find out how.
that's why you wanna put an incandescent lamp of 100-300W in series with the power cord.
it'll be low resistance at low currents, so you'll get almost full voltage on unit, but if there's a short, it'll increase, turning on, and limiting current, so fuse lives (to regret life) another day.

[Anonymous No.2569324]

>>2569320
is that a dim bulb tester? I made one of those a while ago, thanks for the reminder for me to get it out again

[Anonymous No.2569329]

>>2569281
>>2569304
>>2569311
I've changed all of those and it still didnt help. A little bit yes, but not like 8 times.

[Anonymous No.2569334]

>>2569329

of course not.
you also have to lower the turns ratio.

[Anonymous No.2569349]

>>2569329
difference is because you set magnetic coupling to 1, change it to something like 0.99 or lower and you'll get similar results.
For better simulation you would also need to know winding resistance.

[Anonymous No.2569377]

>>2569349
Waaaaaaaah finaly, this is the correct answer. Who would have thought that 0.001 makes that much difference. It's not 1 to 1 equal result still, but difference is now much smaller. Thank you!

[Anonymous No.2569384]

>>2569377
when coupling is set to 1 spice behaves somewhat strangely, essentially significantly reducing overall reactive components. If you change your transformer primary to something like 10mH for 20kHz, you should get around same results in falstad. As it is with 1H or 4H at 20kHz, it severely limits power transfer which is somewhat bypassed with that .001 value

Basic formula for reactive impedance (inductor) X(ind) = 2*pi*f*L
For transformer is slighly different, takes into account secondary reactance as well and this is where it fucks up with "1".

[Anonymous No.2569399]

>>2569377
Please show screenshot with transformer parameters.

[Anonymous No.2569409]

What do you call these? Is it possible to buy generic ones and use them in a DIY project? Is this a soft resistive button type, so basically an analog button that requires a custom PCB pad?

[Anonymous No.2569415]

>>2569409
"silicone membrane keypad"
The translucent membranes are meant to be used with a backlight. They work like vidya game controller buttons (carbon contacts).

[Anonymous No.2569416]

>>2569409
>What do you call these?

buttonpads.
musician type websites sell 'em in all sizes.
alone or as a full kit with PCB.

[Anonymous No.2569433]

So I'm really new to electronics as a hobby. I've fiddled around a lot with arduino and making some fun little projects. I'm at a loss, however, as to how i take the step away from development boards like arduino. Like, say I prototyped a thing with an arduino, now I want to make a couple of those to give to friends. How do I go about knowing what raw components I need? Especially, how do you know what IC you need and when. It's all so confusing.

[Anonymous No.2569445]

>>2569399
>>2569384
Yep, it's kinda same now. Ive chosen exactly the same model of diodes in CircuitJS. I also found my mistake in spice, cause ratio of inductance should be squared.

So it goes like that 180 / 3.6735 = 48.9999 and the square root of it gives ratio of turns 7.

[Anonymous No.2569519]

Why are most power supplies single rail, even the fancy expensive bench supplies are all single rail. What if you want to power your power amplifier or just play with dual rail op amps? Or the idea is you stack two single rail supplies and configure them as + GND -?

[Anonymous No.2569526]

>>2569433
parametric search digikey/mouser or equivalent

[Anonymous No.2569577]

>>2569519
you can buy wall warts with +/-12V outputs, maybe more. they shouldn't cost more than $5-$20.

There are also dedicated DC-DC converter chips from digikey (which come in a bulky plastic package), or you could get an IC like the MC34063 which can either buck, boost, or invert DC voltages to any value depending on what feedback topology you pick

[Anonymous No.2569602]

>>2569577
Yeah I was just wondering if apparently there's no demand in the industry for dual rail bench supplies since I've never seen one.

[Anonymous No.2569607]

>>2569433
Read the arduino schematic to get familiar with it. Same for the MCU’s datasheet, check out recommended bypass caps, crystal and internal oscillator specs, input voltage range, that sort of thing. Get used to programming via ICSP too. Also see how much memory your code uses to see if you can downgrade your final project to a mega168 or tiny84 or whatever. Build a serialUPDI programmer too so you can use more modern (and cheaper) AVRs. Then it’s just a matter of finding MCUs that are actually in stock, good luck.

>>2569519
You basically never need a variable split-rail supply, just common values like 12V and such. So make one out of any old transformer.

>>2569577
>DC-DC converter
>for audio

[Anonymous No.2569626]

Are there any spice models that apply the actual internal schematic diagram for the LM358 or other jellybean opas? It would be helpful for anticipating behavior outside of the datasheet parameters (ex: output saturation). In the past I found one for the TL431 which I've got a lot of mileage out of in using it for slightly weird applications. Also I don't care if the datasheet schematic isn't 1:1 with the die, shut the FUCK up.

[Anonymous No.2569641]

>>2569607
>has never studied the TB-303

[Anonymous No.2569642]

>>2569641
Thanks, I hate audio

[Anonymous No.2569645]

>>2569641
Allow me to amend my statement:
>DC-DC converter
>for hifi

[Anonymous No.2569650]

>>2569645
>hifi

[Anonymous No.2569655]

>>2569650
are those les paul hifi crystals

[Anonymous No.2569657]

>digikey 2 items with the exact same product, except it has a different package quantity.
DRV5032ZELPG
DRV5032DULPG
why?

[Anonymous No.2569681]

>>2569657
>digikey 5 items delivery costs more than those items combined
Why?

[Anonymous No.2569690]

>>2569681
digi isn't cheap but the shipping arrives in 24 hours (for me).
for aliexpress, the situation is the same (unless you only buy one item for $2, when you buy bulk all from one store, it's actually cheaper to switch to the tracked shipping then the cheap untracked shipping, but it depends on the store, and how many separate items you get, and tracked shipping is similarly priced to digi shipping).
I will say that aliexpress sells certain products for 1/100th of the price of digi, but who knows if what you are getting is legit or if you will use all 100-1000 pieces.

[Anonymous No.2569698]

>>2569657
probably one is tape, one is reel?

[Anonymous No.2569704]

Quick question, would it be better to use a bjt to drive an LED in saturation or active region? I think if I adjust the Ib current to get the required collector LED current, I can save on a resistor, is there any downside of doing this (such as stability)?

[Anonymous No.2569714]

when i connect this thing to power, the LEDs slowly light up (not desired) and touching my hand to the desk, waving it around the board, and and touching the metal plate all mess around with the brightness of the LEDs (which aren't even supposed to be on)

is EMI fucking me up?

[Anonymous No.2569716]

>>2569714
I don't know what the circuit is doing, looks like a digital circuit, but unless it's high frequency stuff, usually glitches like that are due to bad connections or cheap breadboard.

[Anonymous No.2569721]

are square waves just bidirectional tvs?

[Anonymous No.2569723]

>>2569704
Generally the hFE is too variable across temperature for the output current to be reliable. If you have sufficiently matched transistors then using a current mirror can be sensible, at least if you want to drive a lot of LEDs in parallel strings. I can't see a temperature-hFE graph nor an hFE temperature coefficient in any of my datasheets, but you could try measuring it yourself by dunking a linear BJT current driver in ice water and in hot water. If you're fine underdriving your LED to ensure it never gets above its maximum (e.g. 20mA) then go for it, otherwise I'd tend to keep the collector resistor.

If you really want to reduce your passive count, consider using a "logic transistor", which is apparently a BJT with a built-in base resistor. An array like the ULN2003 also works if you've got multiple LEDs to drive.
Using a logic-level MOSFET like a real post-1970s electronics enjoyer is an even better option, I'd recommend the good old BSS138 or the AO3400. If you're a THT pleb then you're probably stuck with the ancient 2N7000, but it's not awful.

>>2569714
Your LEDs aren't not bright enough because of EMI, rather they're only turning on because of EMI. They're getting enough 60Hz capacitive coupling to you and your surroundings to turn on, meaning they have a decent area to act as an antenna, while not actually being connected where you want them to be. As the other anon said, check your shitty breadboard connections, if not your wiring.

>>2569721
take your meds

[Anonymous No.2569724]

>>2569723
>take your meds
huh?

[Anonymous No.2569725]

>>2569716
>>2569723
the breadboard itself is pretty decent quality, so the connections are most fine.
from what i understand, when you have a bunch of loose/parallel jumper cables like i've got, it makes it far more susceptible to EMI, right?
i was playing around with it, and it turns out the LEDs were slowly increasing brightness far quicker when my foot was resting on a cable that's running from my monitor under my desk.
pretty funny, but does mean i'm going to have to be less lazy and cut some cleaner wiring to actually get this shit working.
thanks for reaffirming bros

[Anonymous No.2569770]

>>2569657
When I look them up, I get actually different parts with different function.

[Anonymous No.2569785]

Looking for the reverse end of this. Building a appliance mains breakout box with banana sockets and internal current transformer but I also want to hook up a scope to the line terminal for data logging and power quality analysis, so I need some kind of little lug that I can hook onto with a probe tip while it also being absolutely retard proof, or at least to the same extent any mains rated socket is designed to.

[Anonymous No.2569867]

I need a cheap but very accurate ADC module. I don't care about resolution much, if it measures +-0.001V, which is less then 1024 samples, very accurately I will be happy.

[Anonymous No.2569970]

can someone identify this for me?
are these smd chip resistors or smd capacitors?
(the green "0" ones)

What would I look up on digi-key to get one

[Anonymous No.2569981]

>>2569970
Also the schematic has them labeled as "J" not "R" OR "C" for resistor or capacitor.
What is J?

[Anonymous No.2569992]

>>2569867
What voltage you'll be monitoring? How noise is your supply?
Without knowing shit about application just any 16bit ADC module and don't worry too much about it

>>2569970
jumper (0R)

[Anonymous No.2569994]

>>2569992
a 0hm resistor?
Thanks

[Anonymous No.2569995]

>>2569992
>jumper (0R)
Do you have any idea how I find this same part?
These part sites don't really have an option for jumper

Thanks

[Anonymous No.2570001]

>>2569995
literally 0R resistor, any

[Anonymous No.2570016]

>>2570001
ty

[Anonymous No.2570021]

>>2569995
why do you need part for jumpers? just solder anything to bridge the connection and you're good

[Anonymous No.2570026]

>>2570021
why ask why
try bud dry

[Anonymous No.2570043]

>>2570021
Just trying to repair it back to original form.
I'm not an electrician, and have never had to order a parts set like this just trying to make this easier on myself

[Anonymous No.2570046]

>>2570043
If the PCB is used for different models, then jumpers are placed by machines to bridge traces where components would be on another model's board.

[Anonymous No.2570049]

>>2570043
They're also for jumping over traces so you don't have to go around– or through to another layer.

[Anonymous No.2570059]

>>2570046
>>2570049
Thanks for the replies all.
made my order hope all goes well.
Cya

[Anonymous No.2570060]

New thread anyone?

[Anonymous No.2570312]

>>2569785
They exist, google:
Through-hole test point loop terminal

[Anonymous No.2570343]

>>2569995
literally just solder a piece of wire between the pads

[Anonymous No.2570365]

I want to step an ATX power supply up and down. I think I want to use a Cuk converter topology, the only issue being that the output is negative relative to the input. I think I can just disconnect the ATX's ground connection and instead leave it floating (or tied to ground via a 1M resistor), does anyone have experience doing this?

[Anonymous No.2570372]

how far over capacitance can i go with these tiny smd capacitors?

I pulled some tiny caps from a board and mixed them up. 2x tiny brown ones - one is .030nf & one is 0.34nf. Using 0.36nf should be fine for both right?

bigger issue is the 2 tiny white ones. one is 22nf, other is 10nf. If i use a replacement 22nf for both, will it fuck things up?

I have no schematic, and they are on a floppy drive..if it does fuck up, will it be writing bad data?

[Anonymous No.2570376]

>>2570372
Can only go over capacitance if they're just bulk filtration capacitance, where decreasing the corner frequency doesn't matter. If you're doing RF or audio filtration with such tiny caps, or keeping a crystal oscillating properly, chances are you can't just change them willy-nilly. The 340pF and 30pF are almost certainly critical values like that. The 22nF and 10nF caps are much more likely to be bulk capacitance that doesn't matter, see if you get continuity to V+ and GND from them. Upgrading their values shouldn't be much of an issue if they are just across power rails, but if you're buying more parts anyhow I'd just buy 10nF too. Or just get an assorted pack for pete's sake.

[Anonymous No.2570394]

>>2570312
yeah, I need that but in a hole so I can't poke my finger into it, the test point will be at 250Vrms.

[Anonymous No.2570446]

These displays either comes with an adapter board with spi interface attached or comes naked with a ribbon cable.

The first kind with the adapter is a bit too wide, they put the pins/through holes on the sides and I don't want that

Can I buy the naked displays and the adapters separately? I couldn't find such adapters so I am starting to think that they need to be somewhat unique for each display type but maybe I am just searching for wrong thing

[Anonymous No.2570526]

>>2570372
>I have no schematic
beep one out

[Anonymous No.2570535]

Anyone know how higher pixel lcd ttl communication works? Got.one of those utronics raspberry pi screens but I'm more than certain the graphics chip is busted. It drives the back light but nothing else. The touch screen still works. Looks like it uses a seperate micro controller for that. I'm not.aure if the LCD screen itself works but I'm assuming it does. I dont have a way to drive it through. Due to the complexity of the graphics chip itself I'm not sure I can fo.a replacement without knowing a little bit of programming. Would be cool to salvage something from this or get it working again.

[Anonymous No.2570548]

>>2570535
they mostly use high speed parallel fifo to clock in pixel data

[Anonymous No.2570572]

Why tin doesn't want to stick to my solder iron tip? Molten tin blob just rolls on the surface of wood and refuses to stick on the metal lol. Wtf

[Anonymous No.2570575]

somebody who's ever built something with a W1209 temp controller and can help me out? following pic related schema but the heater won't increase temp no matter what (works with direct current), I'm a newb but this thing can't be so difficult, I'm guessing defective board at this point but I can't really tell

[Anonymous No.2570578]

>>2570548
If I got the data sheet for the graphics processing portion could you tell for sure? Do you think I could drive it with something much slower? I assume the LCD wouldnt be great for much but I believe I can salvage the board if I can determine the LCD does actually work.

[Anonymous No.2570588]

>>2570572
dirty/oxidized surface > use a bit of sandpaper. and use flux
dirty solder iron tip > clean it with some tin/flux and wet sponge or a wire sponge
low iron temp

[Anonymous No.2570590]

>>2565489
I'm having trouble with my furnace, about once a week power to the controller board appears to drop out. turning the breaker off for a few minuets gets the furnace working for another week. A new board costs $400 so I'm taking a crack at fixing the board myself.

I haven't found any obvious problems but have kinda sorta duplicated the problem by disconnecting a 7805 regulator, and I have found and replaced a few marginal capacitors. the voltage feeding the 7805 is 20+ volts and the regulator does get quite hot even though the board only draws 0.03A when powered with a bench power supply. I suspect the 7805 is going it to a overload/thermal protection mode but I haven't observed this happen, when the board is installed in the furnace or on the bench.

The regulator doesn't have a heatsink and gets almost to hot to touch but should be within its operation range, when the furnace is running. I have replaced the 7805 and it's output cap.

If, the problem ends up being the 7805 should I replace it with one of these switching buck converter drop in modules?
https://www.aliexpress.us/item/3256802953871546.html
and has anybody had any experience with a 78XX regulator becoming flaky like this?

[Anonymous No.2570593]

>>2570575
https://support.envistiamall.com/kb/w1209-12v-50-to-110c-digital-thermostat-temperature-controller-module-installation-and-operating-instructions/

[Anonymous No.2570599]

>>2570593
pic rel from the article is pretty much what I'm doing, also tried with separate power supplies without success

[Anonymous No.2570605]

>>2570590
It's harder to diagnose because it is an internment issue. U would replace the regulator and caps if it doesnt fix the problem there is something more going on and you might need to seek those who understand how the furnace control cycle works.

[Anonymous No.2570610]

>>2570588
> dirty/oxidized surface > use a bit of sandpaper. and use flux
> dirty solder iron tip > clean it with some tin/flux and wet sponge or a wire sponge
I sanded all surfaces and used shit tons of flux, my whole apartment stinks as fuck. Tried two different types, one is solid amber block, another in syringe. Syringe one stinks so badly i can't use it at home. Anyway nothing helps, tin just rolls on the surface and doesn't stick to iron tip.

> low iron temp
I've tried all temps from 250 to 400 Celsius. Nothing is changing, on lower temps it literally doesn't melt, just warms up the whole pcb and it's components.

HALP

[Anonymous No.2570617]

>>2570610
Enjoy your cancer

[Anonymous No.2570620]

>>2570605
the 7805 only powers a microcontroller a few status LED's and some transistors to switch all the relays, it could be the microcontroller but it's contents are read protected so I'll be buying another board in that case :-(

[Anonymous No.2570624]

>>2570610
1. Soldering iron tips shouldn't be sanded.
2. Your iron sucks. Your tip sucks.
3. Your flux and/or solder are shit.
4. Too much heat.
5. You're doing it all wrong.

[Anonymous No.2570628]

>>2570599
Does your battery have enough juice to power the heater?

[Anonymous No.2570645]

>>2570617
> Enjoy your cancer
Thank you.

>>2570624
> 1. Soldering iron tips shouldn't be sanded.
Too late.
> 2. Your iron sucks. Your tip sucks.
Okay, can you recommend cheap but good first iron with tips, that are able to solder small components?
> 3. Your flux and/or solder are shit.
Okay, which ones I need? On the syringe it's written RMA. Which solder I need?
> 4. Too much heat.
It doesn't melt below 300°C
> 5. You're doing it all wrong.
Bro im shaking right now, it's not fun, I remember I did the same with old shit iron as a kid and it worked flawlessly. Now nothing works.

[Anonymous No.2570649]

>>2570610
Buy a tip-tinning solder paste and give that a shot. Buying a new tip is probably advisable. Ensure you don't bring its temperature too high, 400 is a recipe for low tip lifespan.

>>2570620
Maybe a relay coil is shorting? Are the relays 5V coil or are they being switched on the higher voltage?

[Anonymous No.2570659]

>>2570628
yes of course, it's a 12v 5a psu, heater works just fine when connected directly, but I need temp control hence why I'm trying to get this board to work

[Anonymous No.2570665]

>>2570645
>can you recommend cheap but good first iron with tips
Minimum power of 70-watts with temperature control, using type T12 tips. I won't suggest any brands.
>On the syringe it's written RMA. Which solder I need?
RMA is good, but get MG Chemicals brand flux, and Kester 44 (flux core) solder.
>It doesn't melt below 300°C
Seems like your iron isn't accurately controlling the temp.
>I did the same with old shit iron as a kid and it worked flawlessly. Now nothing works.
Buy a real soldering iron if you plan on using it often. Chinese metallurgy isn't great.

[Anonymous No.2570666]

>>2570659
Did you probe for voltage between K0 and ground?

[Anonymous No.2570673]

>>2570645
Here's an iron that's way better than it should be for the price: https://www.amazon.com/Soldering-Thermostatic-Digital-Controlled-Temperature-Adjustable/dp/B086WB9HM4
Modern irons with T12 / T(whatthefuckistheotherone?) are so fucking nice compared to the old shit, even this dirt-cheap piece of shit one is heaps better than anything Radioshack sold.
This cheapo will heat up to 350 in about 10 seconds. The ones that are actually good will do it in <5 seconds.
The tips are infinitely replaceable, come in a shitload of styles, and replacing the tip also replaces the heater and the temp sensor.

That RMA flux is not ideal for hand soldering. "Rosin Mildly Activated" is a low-activity flux, it's great for reflowing boards, but shit for hand soldering components in my opinion.
Personally I use and recommend a Chip Quik CQ4LF flux pen for small stuff and portability, and a tub of cheap paste flux for everything else.
If you buy a Chip Quik pen, be sure not to accidently get one of their identical flux removal pens.
Cheap paste flux, I like the generic slightly yellow shit, comes dirt cheap from China. Here are some brands I've tried that I'm pretty sure are the exact same shit:
https://www.amazon.com/dp/B08BLF62PG/
https://www.amazon.com/Delcast-Rosin-Soldering-Flux-Paste/dp/B00SVESNTC/
https://www.amazon.com/Solder-Soldering-Rosin-Lead-Free-Electronics/dp/B08MVXW4RY/

(1/2)

[Anonymous No.2570674]

>>2570645
>>2570673
I don't know what solder you have, but nowadays there's a big push for lead-free solder. It's almost entirely garbage, avoid like plague.
Silver-bearing solder can be good, but is uncommon for reasons I don't understand. I just finished a 10 year old roll of 56/40/4 and I'm pissed I can't find more at a fair price.
Generally, you want regular old fashioned solder with plenty of lead and a rosin core. 60/40 is totally fine. The solder in that Plusivo Amazon listing I linked above is fantastic, cheap, and you can get it in different diameters. Personally I think thin is better, I usually use 0.4mm - 0.6mm solder.

Tip tinner can be good to have, but noobs often get it in kits and overuse the shit out of it, thinking they should be using it every time they fire up the iron. https://www.amazon.com/s?k=tip+tinner
It's for cleaning and tinning the tip of your soldering iron, and one of these itty bitty little jars should last ages if you take care of your shit.
I have two little tins of the stuff that are both over 15 years old. They get used pretty rarely.

If you don't have a tip cleaner as part of your setup, get one. If your tip cleaner is a damp sponge that's older than you, time to upgrade.
https://www.amazon.com/s?k=brass+sponge
This you should be using constantly while you're soldering. This will do 99% of the job of cleaning and maintaining your tip.
You need SOMETHING to wipe the tip. Never wiping the tip lets shit build up, until there's a layer of oxidized mess on your tip that doesn't flow solder.
A tip can also be lightly brushed with a soft brass bristle brush, but be warned that most "brass" brushes are Chinese lies, and are actually brass-plated/coated steel brushes that will damage your tip.

Clean your tip, clean it while it's hot, tin it. If you absolutely cannot get the tip to tin, then replace the tip.
If you can't tin your tip, it's not going to solder shit, and trying will be a frustrating waste of time.
(2/2)

[Anonymous No.2570684]

>>2570649
the relays are all 24 volt, they are all switched with a transistor connected to the microcontroller, the microcontroller does a power on self test of the board and possibly a test at every call for heat and will show an error through a diagnostic LED. It would likely detect a fault like that and refuse to operate.

I can't really bench test the board because it can't see all the sensors and motors and just sits in fault mode until reinstalled in the furnace.

[Anonymous No.2570689]

>>2570684
Change the battery in your thermostat first.

[Anonymous No.2570691]

>>2570689
thermostat is powered by the furnace, 24 VAC 3 amp transformer.

[Anonymous No.2570752]

>>2570526
i 'love' when a one or two line 'to-do' list item becomes an 8 item, spreadsheet and image collection.

I thought about it, but i didnt know where to post it when im done. or it would just sit in my lonely webpage doomed to obscurity like it possibly has before

[Anonymous No.2570753]

>>2570666
yup giving 0V, I understand on heating mode it should output 12V until the target temp is reached but it just doesn't do anything hence my frustration. temp readings and configuration are ok, also thanks for your time anon

[Anonymous No.2570761]

>>2570753
Just a wild guess, but it's probably the relay malfunctioning. If the micro on the board is toggling the base of the relay driver transistor, it's definitely the relay at fault. Test the voltage regulator output for good measure.

[Anonymous No.2570771]

Is it possible to kill one of these regulator modules by having only one of the input terminals connected?
Because I think I just did that. The input terminals are shorted now.

[Anonymous No.2570772]

>>2570446
>Can I buy the naked displays and the adapters separately?
Yes. But if you are asking this question you probably don't have the skills to make it work.

[Anonymous No.2570779]

>>2570771

[Anonymous No.2570789]

>>2570771
>possible to kill ... regulator module by having only one input connected?

not possible.
a 1-wire source cant drive any current into anything, so cant kill anything.
(unless you're working at 1000's of volts in which case air can be a return path)

[Anonymous No.2570792]

>>2570772
I am not asking if I can make adapters myself, asking if they are sold separately. I believe I can attach a ribbon cable to it if I can buy them

I can't find such adapters so either they don't exist (my guess is each display is too unique and requires its own adapter) or i am searching wrong

[Anonymous No.2570803]

>>2570792
I think you don't understand what you're looking at.
Those SPI screens require little to no external hardware to operate.
The "adapter" you're describing would literally just be a breakout board for the FPC/FFC connector.
At most, you need a little extra if it's got a touchscreen, depending on how you intend to use it.
Here's a complete schematic for one of those 2.8" SPI touchscreens you find all over for cheap: http://www.lcdwiki.com/res/MSP2807/MSP2807-2.8-SPI.pdf
You can ignore the SD card stuff if you don't need that too.
It's just a connector for the LCD, 1 transistor, 4 resistors, 2 capacitors, and the XPT2046 touchscreen controller. If you want to handle the resistive touchscreen yourself and not with an SPI controller, then you can eliminate the XPT2046, 1 capacitor, and 1 resistor.
So easy it hurts.

[Anonymous No.2570808]

>>2569785
>Looking for the reverse end of this.

you can make or buy one of these.
one end connects to scope tip.
other end has a banana plug in a shroud.
in the box, you put a recessed banana jack.
like those in a voltmeter.
there's one where the shroud actually retracts, like foreskin. so so kawaii.

[Anonymous No.2570811]

>>2570792
>>2570803
For most of those common ILI9341 and ST7789 SPI displays, which are the ones you'll find looking at 2.8" screens, you'll need either a 40p 0.5mm FPC connector, or an 18p 0.8mm FPC connector.
If you want an "adapter", buy a breakout board for one of those connectors, they're all over Aliexpress for a couple bucks.
For those fat 18p 0.8mm ones, you typically don't use a connector at all, you solder them directly to a PCB.
The screens are also readily available, all over Aliexpress for just a buck or two less than buying a complete module already sitting on a PCB ready to use.
If you want to save yourself the trouble, finding a screen that's ready to go in a format that works for you might be easier.
Lots of the Raspberry Pi ones for example are "borderless," the PCB is matched to the size of the LCD, the connections are entirely behind it.
Don't be afraid if you see a 26-pin connector, read the documentation, they're often only using 8 of those pins, with 9 not connected, and the other 9 for 3.3v/5v/Gnd.

Get on LCDwiki.com to learn more about some of the really common readily available chip screens floating around. It's not comprehensive, but it's a great resource.

[Anonymous No.2570814]

>>2570808
>the shroud actually retracts

figures i'd find a photo *after* i posted

[Anonymous No.2570815]

>>2570803
Hmm, i thought there was more to it and there was an IC that drives the board. Wasn't aware that those lines on ribbon cable are directly exposed. Thanks anon

I guess what I need first is a breakout for that fpc so i can connect them to MC

[Anonymous No.2570819]

>>2569725
>from what i understand, when you have a bunch of loose/parallel jumper cables like i've got, it makes it far more susceptible to EMI, right?
It's not as much EMI as the parasitic capacitance (breadboard are basically built using 2 pieces of conducting material next to each other for each row/column, creating what is basically a capacitor) and the wires being very long create parasitic inductances. This is definitely an issue at high frequency, but that's not exactly EMI since you need an external source of interference to affect your circuit. If you want though, post the schematics for your circuit and let me know how fast it's frequency is, and i'll try to help a bit more. If you want to give it a try though, try to improve your bread board by moving your switch and your button/IC on the bottom of the bread board to the top next to your main IC. Then wire them a little bit better by running copper wires (not jumpers) between the different ICs as short as possible and as flat to the breadboard as possible. Another tip I can give you is to try to reduce the frequency (clock signal) to something like 10 hz, see if it works, then increase the clock cycle slowly (maybe 1 decade at a time) and see if it's starts glitching after a certain point, it will give you a better starting point. My best guess though is still your breadboard connections, especially the ICs. It might look like they are all the way in, but they are notorious for making bad connections. If you have an oscilloscope, try to read the voltages at each pin by connecting directly to the IC pins, don't do it through the breadboard pins.

[Anonymous No.2570823]

>>2570575
>W1209 temp controller

you can rule out if the power supply is just too weak for the load by replacing load with a 12V lamp.
lamp will provide enough heat to affect sensor if it's close.
even simpler: play with the Set Temp while listening for relay to click.

[Anonymous No.2570829]

>>2570815
They are hilariously easy to work with.
>>2565040

[Anonymous No.2570835]

>>2570819
>>2569725
One last and easy thing to add to this, take your setup and try to run it in another place in your home, preferably somewhere away from other appliances or power lines if you can. If that doesn't work, go to the kitchen and get some aluminium foil, wrap it around the bottom and top of your bread board and tie that foil to your ground, see if it improves things. Easiest way is probably to get a tiny box to place your circuit in, then wrap it up in aluminum foil. Just make sure it looks clean, any breaks in it and it can affect it's effectiveness. If the faraday cage improves nothing at all, this will definitely point out to a bad circuit (breadboard, connections, wiring, even bad IC), and not EMI.

[Anonymous No.2570839]

>>2570789
huh I guess it died for no reason?
Or maybe a poor connection caused it.

[Anonymous No.2570841]

>>2570839
>maybe a poor connection caused it.

my best guess: it was a poor operator.

[Anonymous No.2570843]

>>2570839
It died of suddenly. Lots of that going around.

[Anonymous No.2570844]

>>2570841
>>2570843
nigga you just plug these shits in that's about all you can do with them
what do you expect?

[Anonymous No.2570845]

>>2570844
Maybe you plugged it in upside down and inside out. Maybe you conjured a small bolt of lightning with your socks on the carpet. Maybe your dog ate it. Maybe there's a solder bridge that you definitely didn't cause. Post a pic with red circles and arrows.

[Anonymous No.2570847]

>>2570845
It was working before

[Anonymous No.2570848]

>>2570835
>>2570819
thanks for all the tips, i really appreciate it. just about to hop into a meeting, but i'll post my schematic and explanation a bit later.

[Anonymous No.2570850]

>>2570847
That's what Xi said.

[Anonymous No.2570853]

>>2570808
Yeah I have that exact probe and add on lead, it actually connects to the ground side of the probe not the tip. I ordered the thing in the bottom of pic related and will be installing a CAT III rated BNC socket in the device, the top one would be ideal but is completely unobtainium atm.

Should work out pretty good, going to put a BNC on the CT output as well which should allow very accurate indirect current measurements. Am I retarded or is it really as simple as ordering a 10:1 CT and putting a 100Ohm load on it's output to get a 1V/1A linear response?

[Anonymous No.2570860]

>>2570848
>>2570835
i've redesigned it since pic related, but i remade it using solid-core wiring rather than a mess of jumpers, and it was still getting the exact same issues which led me to believe that the issue was one of design more than construction.
i think the actual issue was that i made a mistake in assuming that having the 4 pins from the dip switch to the data (Q) lines of the AS6C62256 be sourced only when the switch was closed isn't really effective, and was leading to some kind of bus contention.

[Anonymous No.2570864]

>>2570860
You need to tie the address lines low when the DIP switches are open. Otherwise they are floating and you'll get undefined results.

[Anonymous No.2570865]

>>2570864
aren't the address lines meant to stay at the address that you're writing to as you trigger a write?

[Anonymous No.2570871]

>>2570864
this is my redesign, i figured a buffer would be necessary between the data switches and the bus, as well as decoupling the write pulse from disabling output, just to be sure the timings were right.

[Anonymous No.2570886]

>>2570871
>redesign

a cmos chip with floating inputs is generally not a good combination.
like Sid and Nancy.

[Anonymous No.2570897]

>>2570871
just so i properly understand what you mean, are you saying that the buffer is the correct solution to the issue i was having before?
or, should i also being preventing the inputs to the buffer from floating as well?
from what i understand, the first schematic i posted shouldn't have any floating inputs because of those 4 resistors on the data line

[Anonymous No.2570899]

>>2570886
>>2570897
oh hang on, it's the address line that's floating, isn't it?

[Anonymous No.2570902]

>>2570865
Yes. But they must be 1 or 0 (aka 5v or 0v). Your setup is going to have them floating when the switch is open.

[Anonymous No.2570913]

>>2570899
Please stop trying to cargo cult your circuit. You need to learn what you are doing, not just throw parts at the problem in the hopes the sky spirits will bless your endeavour.

In the circuit here >>2570871 when the dip switches are open, the inputs 1A0-1A3, 2A0-2A3 are going to be floating. That means you can't predict if outputs 1Y0-1Y3, 2Y0-2Y3 are going to be high or low.

The solution is either of the circuits in pic rel for each switch in your dip switch. In your case you want pull down. This way if a switch is open, the line will be at 0v, via the 2 resistors. And if the switch is closed, the line will tied to 5v via 1 resistor. Digital inputs pull so little current you aren't going to get much of a voltage drop over the resistors.

Also, can CMOS chips source enough current to light a LED?

[Anonymous No.2570939]

>>2570937
>>2570937
>>2570937
NEW THREAD

[Anonymous No.2570965]

>>2570578
hard to say, just find the datasheet anyway

[Anonymous No.2570996]

>>2570860
Hello, I've looked at the schematics, and I have some tips.

First, the memory module you're using seems to run on 2.7V to 5.5V, so for power efficiency, you might perhaps want to run it on 3.3V logic. You don't have to do this part, but you have to fix the following:

1. Your DIP8 switch is connected to 5V, and then directly to the AS6c62256 chip. Once you disconnect the switch, the pins 10,9,8,7 are left floating. You need to put a pull-down resistor on each of those pins, a value of 10k ohms should be okay unless your memory module has a somewhat low input impedance, in which case a 1k ohm might be better. There might be an internal pull down resistor inside the chip, but I haven't seen anything in the datasheet, so i'll assume there aren't any.

2. You seem to be driving LEDs directly from the chip's outputs. This is usually not a good idea, you should connect pin 11,12,13 and 15 to a transistor, preferably a MOSFET if the chip can source very little current but a BJT might also be approriate to drive the LEDs. In your case, I looked at the datasheet very quick and it seems it can source 50mA, which should be enough to drive an LED I suppose, but I don't know if that's 50 mA per pin or 50mA total. In the latter, you would be drawing too much current for the LEDs, assuming 20mA/LED.

3. pin 11,12,13,15 are connected to the LEDs and are output pins, but for some reason you also have a switch connected to it. You shouldn't connect a switch to an output, since If those pins output 0V and you happen to have the switch on, you'll short the 5V rail to ground through the chip and most likely destroy it.

4. You seem to have pins 16-19 tied to ground via a resistor but aren't doing anything with them. not sure why you would do that, I assume you don't want to leave it floating? This is not necessary for output pins. Not only is this unnecessary, you're actually end up using an extra 2 resistors and most importantly, wasting power. leave it floating

1/2

[Anonymous No.2571007]

>>2570860
5. You also have the write_flag tied to a switch that is connected to 5V. I don't know how the write_flag is controlled, but in your earlier picture I saw and arduino. If you're doing something and the write flag is low, and you press the switch SW_write, you're once again shorting 5V to ground as in 3.

6.. Whenever your DIP8 switch pin 5-6-7-8 are turned on, the corresponding LEDs D4,D3,D2,D1 will turn on. I don't know if this is intended, i think what you're trying to achieve is storing numbers in Q0/1/2/3 with the dipswitch and reading numbers q/0/1/2/3 you're storing with the LEDs. If that's the case, then ignore this point.

ALSO IMPORTANT:
I made a mistake, ignore point 4 in >>2570996
>4. You seem to have pins 16-19 tied to ground via a resistor but aren't doing anything with them. not sure why you would do that, I assume you don't want to leave it floating? This is not necessary for output pins. Not only is this unnecessary, you're actually end up using an extra 2 resistors and most importantly, wasting power. leave it floating
don't leave them floating since I realized they can be input pins as well (went over my mind). For CMOS, you don't want to leave any input pins floating. So make sure to ground it with a resistor exactly as you did.

[Anonymous No.2571139]

display question anon here
>0.8mm pitch for fpc
What is with this gay 0.8mm pitch that most displays use? It is impossible find anything that works with this pitch, it is all either 0.5mm or 1mm. I just wanted to convert fpc to 2.54mm headers/through holes

[Anonymous No.2571194]

[Anonymous No.2571195]

[Anonymous No.2571197]

[Anonymous No.2571199]

[Anonymous No.2571200]

[Anonymous No.2571202]

>501 posts
We did it, tumblr!