/diy/ - Do It Yourself

>>1586417
first for asynchronous logic

Does /ohm/ have a recommended newbie power supply?
If it isn't a totally shit idea I would want it to double as both a breadboard supply and use it for anodizing small aluminium parts made on the mill.
I would then later keep this first one only for anodizing and risky business, and get a better power supply for bench work.

>want to diy a guitar pedal
>look for schematics
>find more interesting easy pedal schematics
>want to build like at least 7 now
>see that ordering stuff in bulk is cheaper
>might as well order some extra stuff in advance for that sweet discount, like enclosures, pots, stomp switches and common components
>mfw spending nearly €300 on parts when I initially just wanted to build a single pedal
Now to buy tools. Probably looking at another €100 to €200 at least.
...I may have a bit of a problem.

I have a better question. Does /ohm/ have a recommended high voltage /diy/ power supply? I'm tired of the same 30V 5A shit. I'm looking for something like a regulated +/-300V supply that can supply from 0.25-0.5A or so.

I have the best question. How do you get a hold of a laboratory grade 1kv power supply designed to hold within 1v from 0-100 amps?

>>1586431
I've got that one from chinks: XL4015E

It is surprisingly good for the shit tier newbie power supply. Hook it up with 12V brock and you get essentially two knobs to set the voltage and maximum current limitation. Works great for supplying multiple breadboards with whatever voltage you need. It also has liitle-to-no ripple, checked it with oscilloscope, got around 4mV.

The buttons allow you switch between showing voltage, amperage, or wattage.

whack a hydrant
shift with confidence

>>1586443
This is a bidirectional shift register isn't it? I just started looking for one today

>>1586431
yeah, it's kind of a shit idea as the requirements are nearly opposite for bench supply vs. anodizing supply (constant-voltage vs. constant-current, order of magnitude power difference, current fold-back vs. current regulation)

>>1586435
kek, you're not the only person with an electronics habit. that's not that exorbitant of a bill for initial lab stock, esp with enclosures and other mechanical parts for 7 or more pedals. I figure I've got a grand or two in things I might want to build with someday

>>1586438
if you can make good use of that sort of voltage you can build that sort of supply. might start with some of those stock SMPS transformers on alibay

>>1586440
have you tried oral sex

>>1586448
>yeah, it's kind of a shit idea
I kind of figured that it might be
I'll do some more googling on the terms you used and become more informed before coming back

I was reading this article on designing a microcontroller circuit and it just looks like all you need to do is add some capacitors to remove noise from the voltage source and youre good to go. Am I missing something.

>>1586466
Link the article.

>>1586466
>Am I missing something.
Yeah, a thread.

>>1586468
Oh nwm was under impression you were replying to that multimeter-fag thread

>>1586466
Yeah, 5 caps for 0.1uf each as closer to the chip as possible. You also need to make sure your power supply is stable, what's your application?

>>1586431
What's your definition of cheap? Something cheap to me is pic related. Linear power supply so low noise output for electronics. If you dont care about noise get a switching for more amps

>>1586467
thought i did.
>https://makezine.com/2016/09/19/design-microcontroller-circuit/

>>1586474
that depends on the microcontroller. if the manufacturer doesn't specify a decoupling scheme, the general broad rule is 1 cap per Vdd/Vss pair

>>1586442
I have been shilling those things to different people the past couple weeks. They’re pretty great for <$20, just double check with a meter.

>tfw another $7 Amazon package came today!

>>1586526
how can I learn to build my own custom battery packs anon? I want to make something big to power devices for days. I understand ill need a pile if 18650s but how do you set up the control board?

>>1586552
I haven’t even done it yet. I think I need to order the balancing board because this one won’t fit in the Dewalt case. They have a few boards on Amazon but I’m too lazy.

It seems pretty simple though provided you get the spot welding part dowb. That’s another half assed project i need to finish.

But after you decide on the cells, like let’s say you have 10x1500mAh cells and want to make something like an 18v power tool battery, just search for “5s Balancing Board” or “5s bms” and it will give you the board with a handful of points to solder. If you spot weld all your cells together correctly like pic related and solder the bms/balancing wires at the right spots, the board will charge the cells evenly and keep them safe with voltage and current protection.

They cell those bms boards for everything. 7.4v would be a 2s bms, 6 cells for ~24v would be a 6s bms. I think you can parallel them together as much as you want for extra capacity and still use the same boards, like 5 cells, 10 cells, or 15 cells all strung up for 18v would be the same 5s board. Just make sure to use the same type of cells with the same (or very close) charge across all of them when you build it.

How hard would it be to make a nuclear battery from Americium?

>>1586562
try it
post pics

>>1586564
I want to see if it's feasible before bothering to get the Americium.

>>1586570
have you tried google

>>1586571
I found that Americium can be purchased legally, but I couldn't find anything regarding how to actually make the battery.

A little question:
A TVS diode can be useful to limit the voltage between drain and source in a power MOSFET? Most people seem to use it between gate and source, but not that way. If I am going to send it hundreds of amperes through the MOSFET, how would I need to install it for the rest of voltage to fall on?

>>1586559
awesome, thanks. Any recommendations on sourcing reliable 18650s? (even if its on amazon)

>>1586583
I keep buying power tool batteries when i see them on clearance. Amazon is all over the place, there has to be a reliable vendor online somewhere. The consensus seems to be that you should only buy the basic Samsung-LG-Sanyo real brands, not some “SureNiteFire” or “KloudKang Ohmstar” wrapped Chinesium garbage.

>>1586581
>voltage between drain and source
y tho
if you're worried about capacitive coupling from channel to gate, put a smaller impedance on the gate

>>1586581
Pic you have is from this article: https://www.diodes.com/design/support/technical-articles/self-protecting-mosfets-deliver-improved-reliability-in-the-harsh-environment-of-automotive-applications/
Read that and see if that applies to your situation.

>>1586583
There's a guide to real and fake cells on >>>/g/csg, though I'm unsure how up-to-date it is. It might be linked in the OP, else asking there should have someone post it within a day or so.

>>1586583
If you are South American, be aware these things are considered "dangerous elements" as they are potentially explosive, so shipment might be expensive.

God damn it stop feeding the namefag

>>1586664
I think he's a cigarettefag now

>>1586664
Ssh, we're slowly teaching him the trade. Even if his personality doesn't change, he won't shower us with inept questions and the like and might even contribute to the general. Eventually. He even answered some anon's questions about building a lithium ion battery, if barely.

lemming trigger

I've blown almost $100 on components and I just know it isn't going to fucking work with my luck
I have to do a retarded self-funded project for class for a professor who is about to get fired and I have no idea what I'm doing, the cunt has made me hate electronics

>>1586683
Please share details, sounds like an interesting situation.

wirewrapping is so comfy
i replaced duponts with wrapped wire and it saved me so much space a splicing since you can stuff up to 4 wires on a single pin and cut the exact lengths you need too

>>1586559
How can you evenly charge two uneven cells that are on top of each other with that thing when the charger wire connects to them both?

>>1586687
Ya got a wire-wrap gun or tool?

>>1586701
you can see it in the painting

>>1586703
Oh yeah that thing. And it works on those tin-plated MOSFET pins?

>>1586704
it works with any pins that aren't too thick or thin

>>1586723
Even slightly oxidised copper ones? I thought it worked partially on the principle of the copper of the wrapping wire cold-welding to the fresh metal of the gold-plated pins. But if aside from that you'd get a strong joint without it I suppose that also makes sense.

>>1586725
And how would you exactly remove it if it was welded?

>>1586745
It's just a light cold welding, the contact area is tiny so the total strength isn't that high, but it means you get good electrical connection. It says so on the wikipedia article if you're curious.

>>1586624
Shipping in the US is slow too because they aren’t allowed on airplanes.

@1586664
(You)

>>1586689
The cells in series will get evenly charged by the balancing board, although from reading the reviews it seems like you still want to assemble it with cells that are close because most balancing boards are designed to compensate for a small difference. Like if one cell is 4.0V and another is 3.0, a single charge cycle might bring them to like 4.3 and 3.5. Somebody said they tested one and the balancing wires would only put out ~100mA while the rest of the cells are charging at 1A, so 1.1A on a real low cell compared to 1.0A on another cell won’t be enough to balance wildly different cells in one cycle. It could do it eventually, but you will probably damage the cells by then.

And the parallel cells will balance themselves. That’s why a 5 cell, 10 cell, and 15 cell 18v pack will all use the same board. With a 3.8V cell hooked up to a 3.4V cell in parallel, I believe they will eventually balance out to like 3.6V on their own.

>>1586770
>With a 3.8V cell hooked up to a 3.4V cell in parallel, I believe they will eventually balance out to like 3.6V on their own.
While this will happen, it may result in a few (dozen) amps between the two cells, so I'd advise charging them to the same level before connecting them. As far as using the same board, you're probably right about that but I'd expect them to use a different sized current sense resistor, as the higher capacity batteries will want more current.

>>1586746
Well it's possible, but that is not how it holds out, it's simply very tightly wrapped around it and that is it.
The wire isn't even copper as war as i know since it's silver.

I have arduino and a module which has power needs of 4.2V at most.
This is annoying as fuck since i would have to use a buck converter to connect it to an arduino 5V pin, BUT.. what if is put a diode between the arduino +5V pin and and module's + pin? Since diodes have a forward voltage drop of about 0.7V then the device should work right? since it will be getting about 4.3V at most coz of the diode?

>>1586841
Depends on the power draw. The Diode might get hot.

>>1586841
You could also just remove the regulator on your Arduino.
The AVR on it runs happily with 4.2V

>>1586845
Around 200ma, with short 2A bursts for transmission.
It is beyond retarded the module operates between 3.4V and 4.2 while normal market logic levels on devices are either 5V or 3.3V and this means you cannot use any of them, so you have to do annoying shit like voltage diving every data line and buck converting the power supply and shit

>>1586806
That was something I forgot to add. Somebody on this board posted that they tested it once and they were getting a ton of current between the cells with nothing to limit it and I’m no rocket surgeon but I’m guessing that charging at 15C isn’t great for the cells.

And the second part, I’m sure you would want to look at different boards if you’re trying to charge a 5s4p pack with 3000mAh cells. If the board limits it to 1A charging or some shit, it’s going to take a day to charge the pack.

>>1586852
Run your tarduino at the same voltage and bypass the regulator

>>1586869
>bypass the regulator
2 scary

>>1586870
Its totally doable, anon. Dunno about tarduino, but the Bluepill has two pins, 5V and 3.3V, and you can feed the device with any of those, either using the regulator with 5V or by bypassing in with 3.3V.

Same applies to some modules with onboard regulators, you can bypass them, or what the hell, unsolder them and replace with 0 resistor.

>>1586687
you just jewed me out of 11$.

>>1586870
git gud or forever be cucked by needing level converters

What's the difference between the negative terminal on a battery and a real ground?

I've been trying to rig up a fancy switch on my computer for a couple of days, couldn't figure out why it wouldn't work, since all I had to do was ground a pin. And then while I was fooling around I accidentally had a wire connected to the ground on my breadboard against the computer chassis, and suddenly everything worked exactly the way it should. Why isn't a negative terminal sufficient as a ground?

>>1586894
>Why isn't a negative terminal sufficient as a ground?
Because then you're not closing any circuit

You can have the battery in there but its negative terminal needs to be connected to the motherboard signal ground, that way they share a common reference

>>1586852
What supplies the 2A?

>>1586919
cap

>>1586930
Good luck then.

I have a 500g spool of IF 14 solder wire (Sn36Pb37) someone gave me over a decade ago. Is this stuff good for soldering electronics or should I get a standard spool of 60/40?

I don't know if this belongs here or in SQTDDTOT, but how do you test a MOSFET to ensure that it still works? I'm salvaging things from a dead PSU and it just occurred to me that maybe nothing works at all.

>>1586955
Put it in circuit as a switch and see if it does what a mosfet is supposed to do.
And there should be near zero gate current.

>>1586466
Yeah, more or less. Will depend on the chip, though.
If you want a precise clock, make sure you use an external resonator (check the spec for the uC to make sure your choice of resonator will work). Also, if you're making a PCB for it, make sure you don't have ground plane around the resonator, since it will dump noise into your ground.
Also make sure you consider how you're gonna program the chip. If you're using ARM, OpenBLT and a serial port is a braindead easy (though very slow and primitive) way to program your board.

>>1586952
>Sn36Pb37
Obvious typo is obvious
http://www.interflux.com/sites/default/files/documents/en/TD%20IF%2014-06-09-14_0.pdf

>>1587049
Yeah I dun goofed, it's 63/37, but it doesn't look like it has flux. At least it doesn't say on the spool like the one you linked.
Guess I'll buy some flux then so this spool isn't wasted. And some rosin core solder wire for convenience.

>>1586838
lol no, maybe tinned copper, maybe lightly plated silver, but certainly not through

>>1586841
diode voltage drop depends on current. you might overvolt the module if it doesn't draw much current or undervolt it with those 2A surges. 3.4V minimum sounds fishy, link?

>>1587051
63/37 melts a bit more sharply than 60/40. good stuff but if you don't have flux you'll need to add it

>>1587024
>not using the SWD port to program your micro
shamefur

This is some magic shit

I can't really find a definitive answer as to what high temp resistant adhesive to use for putting a new pad on the pcb which was ripped off. The pad isn't linked to a trace but is used to hold in place a vertical tact switch so it's going to also be under a lot of pressure from being pressed. What should I use?

>>1587281
Scratching off solder resist to solder a bodge wire onto the trace isn’t an option? I’d go for something along the lines of whatever epoxy they use to laminate PCBs in the first place. Bonus points for matching thermal expansion rates, if you have that liberty.

>>1587281
solder first, clean carefully, reinforce afterward

>>1587104
>lol no, maybe tinned copper, maybe lightly plated silver, but certainly not through
i meant silver color not actual silver metal

The module is SIM800L

Is ts100 the best bang for the buck soldering iron?

>>1587296
SIM800x uses 2.8V logic levels. e.g. see page 26 of
http://www.sabreadv.com/wp-content/uploads/SIM800C_Hardware_Design_V1.00.pdf
for suggested connection diagrams for various logic levels

Anyone work with FPGAs? I got some ice40 boards (TinyFPGA and Upduino2) and am trying to learn verilog by doing some projects (using apio/yosys/icestorm). Are there any recommended resources for learning verilog? I've taken digital logic and computer architecture classes, but HDLs feel kind of daunting.

>>1587273
waaaaves, man

>>1587297
IMO cheapo T12 tip based stations are.

>>1587297
>$50
>bulkier than a normal soldering pencil
>apparently has handle overheating issues
>power supply not included
you can get a KSGER T12 station for $40

>>1587303
Yes but how is Z = √(L/C)? I'm searching and I've arrived at Telegrapher's Equations.

>>1587302
this is actually not terrible for a whirlwind intro, esp since you already know digital logic
http://www.asic-world.com/verilog/verilog_one_day.html

>>1587305
>>1587304
shut up!
i already ordered it and i am not interested in having buyer's remorse

>>1587305
>>bulkier than a normal soldering pencil
tha't good tho, a true woman needs to have a proper love handles to grab on
>power supply not included
the idea is that you can just plug it into any old usb charger or laptop and you are good to go so you can just carry it around in your pocket as EDC in case you get say trapped in an elevator and need to repair the control board to get out

>>1587305
Z=sqrt(L/C) comes out of finding dI/dt and dV/dt for a tiny section of transmission line and apply a sine, the sines and the d end up cancelling out nicely. http://alignment.hep.brandeis.edu/Lab/XLine/XLine.html

>>1587328
TS100 is kinda shit for grabbing on to with no real finger guard ridge to push against. Then again that's mostly >opinions

>>1587327
>he fell for the TS100 meme
Make sure to talk about it on /g/csg
Do you at least have a power supply to use it with?

>>1587328
No it wants a 24V power supply to get the maximum of 65W, a 19V laptop brick will only turn it into a 40W station, which sounds a bit lacking for heavier work. And a USB charger won't even get the element to turn on. For EDC I've got one of the 8W USB irons, which should work in a pinch. Though I've actually neglected to carry it in my bag this year.
>in case you get say trapped in an elevator and need to repair the control board to get out
lmao I wonder if this has ever happened? A TS100 is great to put in a car repair kit as you can run it straight off the battery, provided you whip up a cable for it, but I'm not in that situation myself.

>>1587337
worst case scenario i can just 3d print an additional grip that can be attached to it

>>1587345
>Do you at least have a power supply to use it with?
i do, i can hook it to my bench power supply which has multiple outputs and can easily do up to 30V and 30A

>>1587345
>40W station
Also 40W sounds plenty to me. I have currently a full sized iron that get's plugged to 230V and it is only 35W and i have been soldering with it easily for years now, the only problems i had were with soldering wires to large LEDs because theier backplates are metal for heat conducting so it was very hard to get the solder to even melt

>>1587348
>i can hook it to my bench power supply which has multiple outputs
In which case it should be fine. Provided it's got the correct ground reference for antistatic purposes of course.

>>1587349
Well I know I've had troubles with aluminium-backed PCBs even with my 65W T12. Almost makes me wish I had a 1kW soldering iron, I wonder what the insulation rating of the T12 tip is? I kinda want to run it off rectified mains with a purpose-built controller. In fact I bought an extra tip and holder especially for that experiment, but it's a bit of a pain so I haven't tried yet.

>>1587345
Maybe he could it confused with the TS80, that runs of a QC USB charger.

>>1587357
>Well I know I've had troubles with aluminium-backed PCBs
heat up the back with a hotplate while you solder

>>1587357
The secret to success with aluminium boards or just hueg planes is preheat the board. Cheapo hot air station is handy.

>>1587349
a hot plate or other pre-heater helps
personally, I use thermal adhesive on the heat slug and only solder the pins

>>1587363
use hot air with care, you can distort the lenses on your LEDs if you hold it in place for too long

>>1587360
What voltage does Type-C go up to? Having a smart charging format that tells the flyback converter to change its output voltage could be potentially really useful, as you could use it to charge all manner of things, from laptops to phones to e-bikes and even car batteries. I wonder how easy it would be to share power load on a multi-output power supply like that: I mean like having either two 30W 12V loads or one 2W 5V and one 50W 24V load? I'm guessing you'd need to build both channels to handle 50W, lest the shared heat-sink is the limiting factor.

>>1587362
>>1587363
I would if I could, but balancing an iron in my knees without burning myself would be tough. I'm flatting without access to a proper vice, or even a desk that wouldn't be adversely affected by a hot air station. Yes it's a little stained from flux smoke and patchy heating.

>>1587367
Lenses? I think for these ones it wouldn't matter since the light is all absorbed and re-emitted by the phosphor. And some COBs use direct-bonded silicon LEDs which have no lens at all.

>>1587369
QC3.0 can do up to 20V and 18W
USB PD can 20V @ 5A

why is a closed circuit off and an open circuit on?
this shit confuses me every time

>>1587646
when the switch is closed the lamp is off and when the switch is open the lamp is on

>>1587646
Elementary, my dear anon.

>>1587646
open and closed, like a gate.

the current travels when the gate is closed though.

>>1587646
OPEN = OFF
stop making it more complicated

>>1587646
>why is a closed circuit off and an open circuit on?
It isn't bro.

>>1587369
>lenses
yeah, those 1-5W beads usually have lenses over the die and any phosphor gel. COBs generally do not, but you'll still want to avoid overheating the stuff as good manufacturing practice. then again, for COBs maybe you just need a good bevel tip that you can place in maximal contact with the terminal as you solder

>>1587753
I've got a K-type T12 tip, but I've been thinking that a different sort of tip could be handy also. The spatula-shaped tip might work nicely for removing parts, as I'd be able to dig under the part while I reflow its joints. They're like $13+ so I won't be trying one out any time soon.

>>1587762
those spatula tips look noice
C tips are a nice all-around addition to your collection. they are good for soldering larger leads where the flat of the K blade doesn't fit very well into the space available (e.g. pin grid arrays and dense SMD)

I want to get into fpgas/cplds. Should I get an Altera Max II dev board. Is it possible for the cpld to communicate with an arduino?

>>1587853
if that's what you can afford, sure. I might suggest something from Lattice's iCE line which is like $25 and a bit more modern
and yes, you can implement a UART, SPI or I2C interface on the dev board. you will need to implement JTAG or get a USB Blaster clone if you want to program a configuration into the MAX II (vs. the iCE FPGAs can be RAM-configured and OTP-programmed via an SPI interface)

>>1587646
Unlike water, electrical currents (generally, there are exceptions) don't move through the air (when you talk about circuits). And in order for the currents to flow, there must be a path for it to go through, if this path is opened, the current cannot flow.

>>1587862
Yes but "if the path is opened" could be take to mean "if the valve is opened", like an open door. Not him btw.

Best soldering station for larger projects?

I'm pretty new to the whole thing but I recently bought a kit synthesizer that looks like it's gonna be 100+ hours of work to get going. Don't think my shitty little hand-me-down bottom of the line Weller iron can manage.

Any recommendations for upgrades? I've heard good things about Hakko FX888D and 951 models.

Obviously I don't wanna spend more than $1k CAD since I'm barely even a hobbyist but I'd like something that will last me as long as possible.

>>1587885
>Weller
if it's temperature-regulated, don't dismiss it too quickly. maybe a new tip and some auxiliary tools would be enough to get it back into shape. at most, you might need a new handle?
>$1k
for that price you could buy all the soldering and rework gear to open your own phone repair kiosk
personally I like Aoyue. they use the standard "Hakko" 900 series tips which are cheap and available in many shapes and sizes
if you're working with through-hole components, there are through-hole repair workstations with a soldering pencil and a heated vacuum pencil for maybe $200-300

>>1587889
Sadly it's not a temperature regulated one. Gets small jobs done but I'd rather not risk it on something as complicated and expensive as the PCBs I have handy.

This particular project is all thru-hole but I wouldn't mind some flexibility to do SMD stuff in the future.

Aoyue looks interesting but I don't think they have any distribution in Canada from what I can see from a cursory google.

>>1587892
I think sra-solder.com ships to leafistan

>>1587885
From what I heard, your upper limit of 1k is a fair bit more than most people here spend on their soldering gear. I've got a $40 soldering station and I think it would be fine for more than 100 hours of work. THT work that is. If it's SMT that you're working with, I'd go for a decent hot air station with a variety of nozzles and perhaps even a reflow oven. That kind of equipment would be anywhere from $250 to well over $1000, depending on brand names and such. I also want to mention the existence of inert-gas soldering stations (they blow nitrogen over the end of your tip and onto your work to prevent oxidation), because they're cool shit.

Any ideas what chip to use if I eyed the ATTINY10 but need one additional IO (digital, ATTINY has enough DACs) . Attiny85?
I mainly wanted a small form factor and a low power consumption. I don't need much in terms of calculations or spacce, just a counter and one or two comparisons every 3k cicles or something.
It doesn't have to be an ATTINY either, as long as I can easily get it from mouser or similar in europe, it's cheap, runs in the 3V range and the datasheet is in english.

>>1587892
Personally I fell for the ts100 meme. I don't regret it, it's an amazing iron, that being said a seperate hot air station would definately be worth (especially for smd stuff). Also get some decent tweezers. Should be well under your budget and get the job done. Then again the TS100 is rather thin if you prefer something with a bigger grip you may consider doing something else. For 1000 CAD basically everything is possible.

>>1587903
>ATTINY has enough DACs
itym ADC?
Try the attiny202 or 402

>>1587905
>decent tweezers
I made the mistake of buying some of those super cheap stamped 5-packs of assorted ones. I have been looking at Walgreens and CVS but they’re all small basic ones.

I think I’m going to grab pic related one day. That mat looks nice, I always solder on this little metal tray and shit likes to slide around and the helping hands isn’t the greatest for holding everything.

>>1587907
>Try the attiny202 or 402
Thanks, not sure why I didn't consider them already. Looks pretty much like what I needed.

>>1587917
I think many people did that at the beginning. I certainly did until I got frustrated with the abominations that dare call themselves tweezers.
The mat in pic related seems nice, there's also magnetic ones along the lines of : https://www.ifixit.com/Store/Tools/Magnetic-Project-Mat/IF145-167?o=4 (personally I got some chinese knockoff ones) They won't stop stuff from falling down if you tilt the mat too much or anything but being able to write on the mat is pretty nice. I may consider getting a organizer like in your pic and have a magnetic mat as an inlay. Seems like the best of both worlds.

>>1587923
The one in that pic comes in a few different sizes too. Those little compartments for components look like a good idea beyond the non-slip and non-flammable mat.

My go-to instead of tweezers would still be these little babby Crescents. Home Depot sells that 2 pack for <$15 I think and they’re far better for this type of stuff than any of the other mini pliers I have used.

>>1587926
They feel a bit bulky for my liking, I mainly use the tweezers for positioning and holding in place, not for actually plying anything out of the boards, but if it works for you I may consider getting some.

She doesn’t quite have the balls... there must be too much resistance after adding all of the wires and relay because it blew holes in the nickel with straight short wires. Or that battery is totally fucked but I don’t want to destroy my car battery or drop $$$ on a spare one.

How do I into caps with the spot welder? I don’t understand how they work at all but I can start stripping them from an old stereo and test until it works right but I’m not sure where to start.

>>1587926
>2 pack for <$15
Including the safety glasses?

>>1587933
>caps
For all you care about, they're batteries with a really high current capacity and really low energy density. And a discharge curve that goes straight to 0V I guess. It's possible to whip something up with a bunch of individually charged caps that you clip together and turn on with a switch to give the needed oomph, but most designs I see use at least somewhat sophisticated circuitry for switching. But do some research and figure out how much energy you want to be putting in and over what sort of period. When it comes down to it, you're trying to put a bunch of electrical power into the resistance between two pieces of metal, so to maximise that power you need to roughly know what its resistance is. You could take the impedance matching approach for maximum efficiency, but I doubt that will be too much of an issue with the kinds of ESRs you're likely to encounter if you pick your caps right. By no means will a circuit of cobbled together capacitors work without any thought, but you may be able to pull it off by calculating what sort of series-parallel arrangement to put them in.

>>1587939
Nah I get those for free from work

Somebody suggested a graphite rod instead of the copper screw-nail I saw in the video (only was able to find these small copper coated trim nails). Just tried some 0.9mm pencil lead and it was nice because it didn’t stick like the nails have been doing, but then one of the little graphite rods exploded when I gave it more than just a tap on the button.

I can’t find a regular pencil in my house to rip apart for thicker graphite.

>>1587942
Meh, ok. I thought maybe I could just start paralleling them up until I get a good spot weld.

>>1587943
>>1587944
Apologies for the name.

>>1587943
Pencil graphite has far too high a resistance, it's loaded full of clay to make it hard enough, you'll want a carbon electrode from a dry cell D battery, or something like it. And copper coated iron nails will also likely be insufficient, I'd use solid-core copper wire instead.

>>1587944
It might work fine, but by the looks of that beefy gear you'd be better off keeping it intact, and repairing it if it's dickered. Also charging it up (to 35V) could be a bit of a pain, depending on what power supplies you have lying about.

>>1587947
Maybe it’s the copper nails that suck. I don’t think I have any solid wire here. I’ll go to Home Depot and ask the guy to cut me 12” off the spool.

And that board is from an old surround sound DVD player I will never use again, I was just keeping that main board together because I wanted to see what I could do with the big transformer hooked up and the other little power supply board.

Ok so Im putting a bunch of diodes in series in order to get a higher maximum voltage across them, do I need balancing resistors? If so I'll need some pretty specialist ones (1G HV diodes) which is a bit of a pain.

Lookin' good so far.

>>1587964
No it isn't. Looks asymmetrical and ugly. Show them traces.

>>1587964
Bit of an odd mix of THTs and SMTs, isn't it?

>uv curing solder mask
>transparent container

should I be concerned?

>>1587981
It cures pretty slow, but I'd keep it out of direct sunlight and wrapped up in something light-blocking.
Source: I have a tube

>>1587954
>copper nails
1000A is a lot and every mΩ is one too much.

>>1587990
Actually some of those copper soldering tips look decent for this purpose, provided you can screw or solder them onto some sort of connector. Soldering them with a gas torch would be quite feasible. Personally I have some pieces of a copper heat sink (3mm+ thick) cut into wedges for my MOT setup, but I've never gotten it to weld so the issue might be in the eye connectors screwed onto them or in the way I was just plugging the thing into mains without any sort of capacitors or switch on the primary side. I've heard of people putting capacitor banks before a MOT and switching rectified mains into out of the capacitors into the primary for a short pulse on the secondary, I think. Now that I've got some delicious 1mF 400V caps I might give that a shot.

>>1587958
it's either that or add a few extra diodes in the series and hope for the least possible difference in capacitance between them

>>1587970
I can see how someone might distrust SMT connectors. also it can be a bit difficult to find SMT pin headers on the cheap even if one did trust them
>MOSFETs
I agree here, they should be vertical and have the drain tabs screwed directly to the output bus bar, with some similar arrangement on the source pins to keep the output current flow off of the many milliohms of board

What temperature do chads use on their soldering irons?
I was at the school lab soldering some stuff for my thing and this cute girl walked by and i think she wanted to approach me, but then she looked at the readout on my soldering station which was showing 300°C, which is the temp i normally use and she it seems to me like she just smirked and walked away.

>>1587998
nice pasta
350 here because I'm a leadlet

>>1587998
>using leaded soldering temperatures
John Gammell sets his iron to 370 and makes IPC class 3 joints with SAC305 all day long.

>>1588005
>i use lead free solder
oh god please tell me you are joking, please tell me people like that don't actually post here

>>1588006
Not him but I do, because I often work with components that already have RoHS solder on them and mixing solders makes for a poor joint.

>>1588009
no, that's just a meme
> SnPb, SnPbAg, SnCu, SnAgCu and SnAgBiCu alloys were used in a range of mixtures to make surface mount joints. The reliability of the joints was assessed using thermal cycling with continuity monitoring, and shear testing.
>The results indicate that when solder alloys are mixed the resultant joints exhibit a general improvement in first failure reliability as compared with those soldered using the single alloys. This finding suggests that concerns about mixing of alloys in rework situations, may be unfounded
http://publications.npl.co.uk/npl_web/pdf/matc85.pdf

>>1588010
What about the myth that licking your soldering tip before firing it up gives you lead poisoning?

>>1588011
perfectly safe (N=1)

>>1588011
Drinking tap water is much more effective.

>>1587991
>1mF 400V
Topic is still in the archive:
>>1585625
The energy that gets dumped into the weld spot is defined by I^2R and the pulse time, R being the resistance of the spot. The tips of the electrodes are optimised for the desired contact area. Cables are 6AWG and are all crimped.
>1mF 400V
The ESR is part of the game.

>>1588019
if photo flash caps, they're probably pretty low in ESR. those are usually designed to dump everything in 10ms or less
anyway ESR would be transformed by the turns ratio squared, no?

>>1588019
>The ESR is part of the game
So impedance matching calculations? Fun.

>>1586417
Anyone here ever wound up their own inductors/transformers for a flyback converter? I want to make it run out of mains, and will probably use some old converter IC and small toroidal cores.

>>1587998
320

>>1588006
oh I never got around to answering
yes, I am one of Those People

>>1588059
>small toroidal cores
you might want to design your transformer rather than try to throw a bunch of junk together and hope it works
read datasheets

I found some equalizer part from old boombox. Will it anyhow works if i just connect it to battery and put somr signal on in and speaker on out?

>>1588105
never fussed around with audio stuff. What are those walls on the left side? They don't look like heatsinks.

>>1588109
You mean the pots?

>>1588105
>Will it anyhow works if i just connect it to battery and put somr signal on in and speaker on out?
no

>>1588105
>>1588109
Potentiometers?

>>1588174
>>1588113
Oh, I don't know why my brain did not recognize them, I have like 10 of those linear ones in my desk. rip my last two brain cells

>>1588020
Photo flash caps aren't that low ESR, they're getting the high energy from being ~400V, not from having a lot of coulombs. Transformer makes things more difficult.

>>1587967
You're right, cleaned it a bit.
>>1587970
It is. I got used to SMD resistances, but there are certain parts such as the power transistors that I couldn't find affordable SMD alternatives, so I'll stick with the THT ones. Besides that, it's only one high current diode and external connectors.
Now that everything's in place, I'll have to connect everything together.

Thoughts on this multimeter? Its gonna be on sale soon so I thought I'd jump on it. Theres another one coming up called wh5000a that's better

Anyone here have experience with repairing old computers?
I got a Tandy model 200 and I'm thinking about replacing the internal save battery with a supercapacitor.
The internal battery is a 3.7v NiCd, 60mAh, and is just used to keep the SRAM from losing data while the AA batteries are being changed.
Would there be anything wrong with just replacing the NiCd with a 1F/5v supercap?

Does anyone have any experience with an ads1256. It boast up to 33000 samples per second and 24bit res. But I dont see how to get that or at least read that. Its settling time is around .2ms which would equal 5000 sps. Furthermore if you want to read multiple inputs theres a vid from a guy who used a teensy and only got about 3 differential readings 3 times per ms. So 9000sps. I need to read 4 or 5 analog inputs at 16bit or higher ideally at .1ms but I might be able to make .5ms work which seems like the limit of the device.
Am I missing something or can the ads1256 do more than what I believe. If not are there alternatives. I can make it work, but Id like to have .1ms reading.
Using a stmf4 right now but will probably use a stmf1 when I reproduce it.

>>1588317
probably won't survive being jumped on

>>1588322
You'd need to drop that voltage in one way or another. Read the datasheet for that SRAM can it handle 5v?

>>1588372
You must be fun at parties.

>>1588322
>>1588373
the rating of a cap is just the max voltage it can handle before it has the potential of failing. if you charge it with 3.7V then it will have a voltage of 3.7V

>>1588373
5v is the cap's rating. How's it gonna get up to 5v if the NiCd's charging circuit only provides 3.7v?
Besides, I checked the datasheet, and the power rail for the memory is 5v.
It's from the early 80s, so I'd be more surprised if it didn't tolerate or expect 5v.

>>1588385
>>1588381
Oh shoot you're right.

>>1588374
i don't know i never get invited

>>1588385
A fully charged 3S NiCd has about 4.2V, so no problem.

>>1588417
Ok, Just figured I'd check if swapping a cap into a circuit designed for a battery could have any unintended consequences.
I'd hate to kill a somewhat uncommon computer like the Tandy Model 200.

>>1588240
That a motor driver or something?

>>1586417
I am running power through a Detolf's metal frame as shown in this guide: https://www.j-junk.de/allgemeines/ikea-detolf-mit-leds-wireless-ultimate-version/
The LED strip I used comes with a controller for turning on/off/dimming. When I connect the power/ground directly to my LED strip, dimming/on/off functionality works fine. When I connect the power/ground to the metal frame which connects to my LED strip, dimming/on/off does not work. Does anyone know why?

>>1588462
Interference I'm guessing, the whole metal frame acts like a big antenna, which is both a significant load to the high-frequency dimming and a source of attracting other signals. If you want to dim it without such problems, consider making/buying a buck converter for your LEDs. Current controlled would be ideal. This way it's just the different current going through the LEDs that causes it to be dimmer, instead of PWM (turning it on and off really quickly). Something like this should do the job, though I'm not certain about their minimum dropout:
https://www.aliexpress.com/item/LM2596-3pot/32580214850.html
You may have to run it off 15V or more, a laptop charger would work. I'm assuming that the LED strip requires less than 3A?

>>1588445
Close. It's supposed to be a spot welder.

>>1588317
How much is it? Those leads look really cheap but you can upgrade those. Just remember that most clamp meters won’t read DC current and even then the better clamp meters that do read DCA aren’t the best for reading at the mA level. You may want a second regular fused meter for doing small DC stuff like electronics.

Pic related is like the most affordable and somewhat reliable clamp meter that can read DCA.

>>1588322
if you want days of save instead of years, go ahead

>>1588385
it probably holds data until ~2V or so, you just can't get to it until you get 5V into it

>>1588462
can your controller see the remote? are you trying to transmit IR through an opaque material?
ignore this faggot
>>1588485
he has no fucking idea what he's talking about

>>1588317
>>1588580
If it’s your first multimeter and you’re using it for /ohm/ type stuff (and in general any battery related things) you should get that 2nd one you mentioned. Can’t go wrong for the price, and that clamp meter you posted will be absolutely useless trying to measure current if you’re fucking around with little LEDs and such.

>>1588582
It's not an IR controller.

>>1588585
but are you getting a clear shot between the remote and the controller? does it work okay if you move the controller somewhere else?

How are digital signals encoded in radio waves? What are the names of things I can search for to learn more. I've built an AM receiver already, but I have no clue how to send digital signals to for example, toggle something on or off. Are they just modulated like a normal signal?

>>1588602
more or less. search terms: where you see "modulation", try substituting "shift keying" e.g. amplitude modulation -> amplitude shift keying aka on-off keying (ASK/OOK), frequency modulation -> frequency shift keying (FSK). there's also audio frequency shift keying (AFSK) which modulates an audio tone inside the RF carrier, which is somewhat easier to interface with existing radios. there are more complex means of encoding that increase bits per baud but you'll find them as you research
>how to send
there are many ways to encode information in that bit stream that you just converted to/from RF. ASICs (e.g. HT12D/HT12E) and/or microcontrollers are generally required for reliable operation. some are more robust in the face of noise than others. look up e.g. Manchester encoding, pulse width modulation, NRZ coding
usually the packets include a preamble to sync the receiver, an address to uniquely identify the receiver, some data, and some sort of check code to verify address and data are correct

Just checking before I order stuff
I have a 4hp permanent magnet treadmill motor I want to power
I'm going to buy https://www.aliexpress.com/item//32850214225.html and https://www.aliexpress.com/item//32911906175.html
Then it's just juice out of the wall into the regulator which tunes the current to control the speed, then through the rectifier to make it DC?
It's a 110V 10A motor and this is canada so mains is 110 as well, so there shouldn't be any serious worries, I think?

The speed controller is apparently for 220v, so will it still adjust over the whole range of the potentiometer or will I need to add resistance or something to make it not only span the first half?

Am I missing something that is obvious to people that actually know what they're doing? If so I want to catch it now, not after waiting a month for everything to ship from Chang's warehouse.

>>1588536
Ah, those FETs are in parallel! Got a lot of those pins on it though, they for troubleshooting? Looks like too many for ICSP.

>>1588601
Pretty sure he's literally clicking the buttons on the inline controller, since the pic shows no remote controller at all. That's why I suggested interference/capacitance, because what the fuck else could it be if the thing is working normally otherwise and only the dimming doesn't work?

>>1588585
Is there any sort of remote controller at all, just to be sure?

>>1588584
>not just getting an AN8009

>>1588639
I kinda doubt that dimmer can actually handle 4kW, but you never know I guess. It should run just fine on 110V, but to be sure I'd simply buy one that's made for your voltage. If the motor says 110VDC it's probably running off rectified but not filtered mains (since the peak voltage is 170VDC or so), which that rectifier should do for you without issue. It might be worthwhile to connect a small high-voltage capacitor in parallel with the motor (100nF or so) to prevent switching transients, provided it doesn't have such things internally soldered right near the brushes, which I've seen on some motors. All I can think of that you might want is more safety features, like a MOV and PTC thermistor, perhaps some extra noise filtration too.

>>1588655
Power supply (bottom right) is connected to the controller ((top) is connected to the LEDs

>>1588659
And no wireless controller that speaks to the inline controller? Ok that's what I thought. Uh did you try disassembling it and reassembling it not wired into the shelf?

>>1588660
No, everything is wired. There isn't any wireless component.
It works when not connected to the shelf.

>>1588655
oh, derp
then I'll guess he has input and output swapped and LEDs are getting fed thru a diode, either a discrete one or the FET's intrinsic diode

I'm working on a temperature control module, need some help with conceptual development of the PWM operating the voltage trim of the DC-DC voltage converter.

The idea is to get a DC-DC voltage converter to supply a heating element using lithium batteries, and have an arduino controlling it via PWM. I still need ideas of how to sample the resistance of the coil to calculate the temperature on the negative half of the square wave. I assume it would be pretty easy to use a solid state relay to conduct a sample voltage to the coil after the falling edge.

If I use a digital potentiometer over SPI or I2C or etc, would I be able to have a high enough frequency to control it with an accuracy of 3-5 degrees fahrenheit?

I can include specs/parts, any ideas welcome

>>1588662
>>1588661
But the LEDs are still turning on even if they aren't dimming, aren't they?

>>1588677
Yes, at full brightness

One of the caps for the segment display in this old clock radio popped so I replaced it with an even shittier one, except I don't know why I even bothered. I could just use my phone as an alarm clock these days. When the hell did this become a reflex?

>>1588669
I'd have a constant-current source constantly feeding the coil anywhere from a few hundred microamps to a few milliamps (only noticeable when at the bottom side of the PWM), and reading the voltage across the coil with the MCU's ADC. With some trickery you might get it to sample at the low side of the analog_write, or instead just write the digital_writes with variable time delays in between manually if you really have to. A digital thermometer might be a better option since it won't require calibration of the coil's resistance and won't require having to measure the resistance at a particular time. Considering those things are good to a few hundred kHz sample rate, achieving ±1° should be possible provided you use a PID-style algorithm. I was planning to do something similar using the element of a dumb soldering iron to measure temperature and turn it into a temperature-controlled one, so if you do go that method I'd like to hear back.

>>1588680
In that case I don't believe getting reverse polarity could cause the LEDs to still light.

>>1588682
To be honest, I think modern chinky caps are probably far better than name-brand caps used to be. Though I can't speak for how old that thing is.

>>1588669
if you have PWM, why bother with a separate dc-dc converter? just connect the PWM output to a MOSFET and you'll always know what the state of the switch is. 64kHz is more than plenty. you won't even need an inductor for a resistive load like a heater
as for sampling resistance, an SSR's resistance variation is far larger than the resistance you're trying to measure. you'll need an amplifier to amplify the millivolts across the heater, which should be able to withstand full heater voltage without blowing up. you'll also need a current source that will generate enough voltage across the heater to measure, or a lo-ohm resistor (and another amplifier?) to measure the current through the heater and the total supply voltage, and some math

>>1588677
>>1588680
>>1588685
think harder

>>1588680
Wait actually you can just put an LC filter in series after the controller if the high PWM frequency is the issue.

>>1588690
How would he flip the polarity of the barrel plug? I'm assuming he didn't cut the jack, and I'm like 50% sure he disassembled it to check that the PWM works when it's not attached to the frame. But otherwise that's a very plausible explanation.

>>1588693
the body diode is likely reversed in either case, whether he swapped input for output OR swapped pos for neg, in the latter case it is likely the entire controller is also kill

>>1588695
Well I was assuming the barrel jack was untouched, so just one polarity would be flipped, which couldn't have turned the LEDs on.

>>1588688
The DC-DC buck/boost voltage converter has temperature and amperage safeties, and really stable filtering, which helps that I only have a rudimentary oscilloscope and power supply. It is a considerably expensive IC at around $15 a piece, so an alternative is welcome. A mosfet seems like it wouldn't be very efficient @ 3.7V 15A nominal input. It's a portable application, so excessive power loss and heat would be an issue.

The heating coil would be 0.1-0.8, 0.2 ohms nominal.
>>1588685
I have tons of datasets for the resistance of varying materials at temperature. A digital thermometer isn't really an option due to cost per unit. Mosfet for the sample circuit maybe?

I don't see any issues with manually tuning the sample delay time.

>>1588582
>if you want days of save instead of years, go ahead
Works for me. It just needs to keep the memory live while the AA batteries get changed.
Once the batteries are back in it starts recharging, even if the laptop is turned off.

>>1588685
Can't really argue with that I guess. The caps aren't even name brand in the first place and have decades on them at this point.
It's probably from the late 70s given the appearance and build, and it was already old when I picked it up at a yard sale in the early 90s. The snooze is a capacitive metal sensor bar instead of a button, which teenage me appreciated in particular.

>>1588700
>3.7V 15A nominal input
oh, e-nails, cool
>seems like it wouldn't be very efficient
check out the Rds(on) of Pic related. 2W power loss vs. 50W which is 96% efficient. you might consider a small boost module which you would switch to increase the gate drive over the plain battery voltage, or maybe some sort of bootstrap arrangement
in either case it's probably better than what you're getting from that dc-dc module

>>1588700
Well just note that the components required to set up a current source may end up costing more than a single 3-pin digital temperature sensor. Or even a diode sensor. What's your temperature range anyhow? Just for reference.

>>1588705
It's a nicotine vaporizer if we're being frank. I was looking at 93% efficiency with the DC-DC converter. This looks great, thanks.
>>1588707
Temp range is 200 to 250 C. Looked at some ICs and they were cheaper than I thought. Since the temperature being measured is a nicotine delivery system, the issue would be getting a probe/sensor with the appropriate composition to ensure the user isn't breathing any fumes. Also, the design of the device entails that the temperature must be measure at the coil to ensure the wicking material and the nicotine mixture isn't heated past the limits of the materials.

>>1588712
Well considering the average soldering temperature is far higher than that, a glass diode package might work fine. Just one resistor and a DO-41 diode with the ADC measuring in between. You'd have to do some testing to see if wrapping up a diode in the heating coil gets adequate heat conductivity with as little delay as possible.

>>1588716
The delay would probably be an issue with the glass, and the heat-up time for these devices is extremely fast and would require a lot of testing, but doesn't seem like the biggest issue. Also, you need airflow to atomize the mixture, which would be difficult considering the diode/sensor would need to cover the surface area of the coil to ensure there are no "hotspots" which are considerably hotter and likely to bring the materials past boiling point. I doubt the diode is capable of measuring the entirety of the heating coil

The tempering of the glass from changes of use/environment could lead to reliability issues. Ceramic has been used before in a similar way, and has been met with disappointment for the same reasons. Anything brittle is a no-go. Having a device-specific heating coil/temperature sensor combination seems out of my depth of manufacturing, but is an interesting concept. Really neat.

I think I'm looking at doing a PID setup with a mosfet and a decent heatsink. Switching the gate at kHz speeds with a PWM seems like a considerable amount of delay, but with a little tuning should be achievable. Sampling is still on the table, and this is definitely the pitfall on modern devices. Resistance varies greatly (.01-1 ohm) between heat cycles.

>>1588722
You're probably right in this case, so I'd go with the coil resistance measurement.
And 1ms probably isn't a considerable delay if you do the thermal calculation (∆T = power * ∆time / coil_heat_capacity) to see how many degrees it increases each step. Making it a tenth of your desired resolution should be sufficient.
What are you making anyhow, a tobacco sous vide?

>>1588433
>Ok, Just figured I'd check if swapping a cap into a circuit designed for a battery could have any unintended consequences.

yes, it could have unintended consequences. the dude who said the charging circuit will only provide 3.7V is wrong. possibly deadly wrong. a typical trickle charge circuit will involve a voltage quite a bit higher than the battery voltage, and then use a resistor to limit the current.

in fact, the higher the charging voltage, the more predictable the current is. in an extreme example, a 1000V voltage source with a 100K series resistor will provide 10mA with only a difference of 0.5% whether the battery is fully charged or completely dead.

so, you cap might get charged to, say, 12V. the NiCd wont do that coz it's chemistry acts a bit like a zener would.

>>1588693
>>1588695
>>1588698
I did not touch the barrel jack.
The dimming/on/off functionality works fine when connected directly to the positive/negative terminals of the LED strip. When I connected the positive/negative to the frame of the case, the LED strips light at full brightness and are unaffected by on/off button/dimming buttons.

>>1588728
intredasting
open the controller if you can do so without destroying it. sounds like there's a mystery inside!

>>1588724
I think a huge issue is the thermal properties of SS and nichrome get a little wacky when they're heated red-hot (variance in resistance) but with enough tuning of the pid it should all work out fine. Plus or minus a couple degrees is no problem in this application.

Lol sous vide. It definitely seems that way with how so many different compounds with drastically different properties are interacting to make a vaporizer.

>>1588728
Well that means the WRONG picture (>>1588690) can't be it since the barrel jack is fixed to the correct end of the controller and with the right polarity.

>>1588729
Yes, post the circuit, perhaps it has some curiosities.

>>1588729
>>1588731
I don't really want to because I'll probably break it

>>1588730
So there isn't a direct correlation between temperature and resistance? It's likely due to surface reactions with oxygen under the heat, I know that oxide layer isn't invincible and slowly wears away from thermal stresses. Perhaps Kanthal will work more consistently?

>>1588733
Is it clipped together? You don't have an oscilloscope or some passives lying about do you?

God damn chinks just ship it already!
Whoever the sweatshop manager is in that store they need to get fired for not flogging the lazy ass workers enough.

>>1588736
>he missed the anniversary sale

>>1588726
You should read the fucking manual before making such retarded claims.
The Tandy 200 runs off of 4 AA batteries, and the highest voltage rail it has is the -10v for the LCD.
The internal NiCd is charged directly off the AA batteries, just with two diodes and a current limiting resistor between them.
At the absolute highest, being powered off of a fresh set of AAs, the charger voltage is 5v. As the batteries drain that drops down to 4v.
All of those voltages are well within the spec of a 5v supercap.

>>1588735
There is a correlation, and there's loads of variables. PG-VG ratio/content is one, airflow is another. Kanthal is definitely the way to go after looking at some specs, but the industry standard right now integrates tuning for stainless too, which has the red-goo voodoo I speak of

>>1588735
>>1588731
>>1588729
i just retested it and it seems the dimmer/on/off functionality doesn't work at all even when attached directly to an Led Strip. I don't know why because it was working directly a few days ago

>>1588735
>>1588741
Also kanthal a1 seems to be what smokeshops put on their shelves.

>>1588736
they've got to wait to get it in from their drop shipper. they might give you a fake tracking number just for fun

>>1588744
welp
maybe you zapped the FET with high ESD while putting it together, or just while having it connected to the shelving

>>1588748
Come to think of it I do remember the LEDs turning on for a brief second before turning off when I first connected it to the frame.

>>1588736
Literally 2 days ago. Chill tf out

>>1588639
>The speed controller is apparently for 220v, so will it still adjust over the whole range of the potentiometer or will I need to add resistance or something to make it not only span the first half?

no, these controllers work by something similar to PWM, so the rated voltage is only the maximum allowed, it doesnt have anything to do with the range of variability, which will be 0-100% at either 120V or 220V.

however, the fact that it uses an SCR might be a problem. that's because SCRs lock on when working on DC. if you use them on AC loads, then on each cycle the supply voltage drops to zero which turns the SCR off, and then it can be turned on again at the appropriate time. with a DC load, once it's on it stays on until you power down the circuit. i'm not sure it'll switch off with a full-wave rectified voltage. you have to go below something called the ''holding current'' before it'll turn off.

the other problem is that these speed controllers are not made for motors, but resistive loads. motors are very brutal at turn on and turn off, and will likely kill a dinky controller like the one you pointed to.

>>1588744
Well you might as well disassemble the controller. It's already fucked, you can't fuck it anymore. Perhaps you can just replace the FET or even just a solder joint. Might be an entire PWM IC with an internal switcher though.

>>1588753
Not him, but the motor says 110VDC, so I assume it uses rectified but not filtered mains. Also he's putting the dimmer before the bridge rectifier. I assume things used to just run off unfiltered rectified mains due to the odd prevalence of SCRs in electronics vendors, which are basically useless in any other situation. Except idk, some sort of memory latch or monostable circuit?

>>1588737
you mean the 10 cent dicount? yeah that one really hurt, ping pong sure know how to make a fire sale discount
Also the iron is actually cheaper then that, i am paying $10 shipping so chinks send it from germany and i have it here in 5 days a more importantly can avoid the massive jew sized import tax

>>1588759
>10 cent dicount
No I mean the $3 off $10 for any product coupons, and other such coupons

>>1588768
it's fine, they sell their shit so incredibly cheap compared to what the EXACTLY same thing costs here, that every time i order stuff from ping pong i feel like i'm stealing

>>1588623
Thanks

If relay spec says it's for burger 125v a that it has maximum rating at 250v is it safe to use it in eu with 230v?

>>1588810
coil and contact voltages are indicated separately. contacts are usually specified as a maximum voltage, sometimes ac and dc separately specified. coil voltages need to be somewhat close to the indicated value for the relay to operate and not burn out

>>1588812
I am talking about contacts

>>1588815
It says contacts are rated for 125 with maximum 250

>>1588433
Here's the relevant part of the diagram. The worst case scenario for the 5V capacitor would be to power the machine OFF and connect the supplied mains adapter, a standard Radio Shack 6V 400mA center minus wall wart which is NOT regulated. Somewhere else in the manual 8V is mentioned as the maximum voltage for VR.

What do? Connect a 4V3 Z-diode across the 1F/5V capacitor for peace of mind?

The 3-51FT 60mAh NiCd was supposed to keep the back-up for 5..15 days, depending on RAM size. It is now available as 3.6V 80mAh NiMH.

Public homework: Compared to the 60mAh NiCd, how long will the 1F capacitor keep VB at 2..4V so as to not lose the RAM content?

If I need a diode to direct my current and I have a voltage of 1.2V across it and I want it to let 1.2V through in one direction and block in the other (or almost block, I know that diodes are not perfect) and it states that forward Voltage is 1.2V will that work or does 1.2V forward voltage mean to get a decent result I'd need more like 1.6V or something?
Essentially is forward voltage the point where it "switches"?

If I don't know if something is AC or DC and I measure the voltage and I get
AC measurement( as in voltage measurement with AC settings): 13.6V
DC measurement (as in voltage measurement with DC settings): 6.5V

I'm assuming this means it's AC, am I correct in that assumtion?

Where does the difference come from?
The AC 13.6V comes from sqrt(2)*Vmax right? If I measure DC I assume it fails to measure the negative Voltages or something?
Thanks for clarification

>>1588965
A diode is more like valve than a switch.
It conducts quite well in one direction but blocks in the other.

>>1588965
>1.2V forward voltage mean to get a decent result I'd need more like 1.6V or something?
>Essentially is forward voltage the point where it "switches"?
Yes and Yes

The diode will "drop" 1.2V in forward bias, so you lose that voltage. Current only begins to flow at that voltage.
Ideally, it acts as a one way valve with the forward voltage being required as an overhead to open the valve. There's no "Ideal" diode though, they have a bit of resistance and other properties, so the actual curve will differ a bit from the ideal.
You could use a diode with a lower forward voltage.
pic related. regular diodes operate in the forward bias mode,(some like a zener, are used in reverse bias)

>>1588988
That pic doesn't seem right for basic doide operation

>>1588996
Thanks, that seems to make sense.

>>1588996
>pic doesn't seem right
Sorry, the forum engine refuses to delete it. I'm not well versed in Memetronics 2.0.

With pic related as datasheet, what is the max current i can get from a IO pin without damaging the chip?
15mA for a sum of 45mA across all pins? Or 1mA (no idea what injection current is)?

So i have this vacuum sensor: https://www.sensor-rep.com/pdf/airflow/Posifa_Pirani.pdf

But the datasheet is so confusing.

There are 2 resistors in a package. One is a reference resistor for temperature compensation, and the other one measures vacuum by measuring its temperature.
The datasheet shows a voltage drop (over the measurement resistor) vs pressure plot. They say the resistor is 160 ohms and the heating current is 7mA, but the plot shows a voltage range of 1.1V - 1.55V instead of (160ohm*7mA = ) 9.8V-ish range.... What is going on?

I have no idea how i should set this sensor up to produce a voltage drop shown on the plot... Can anyone help me out?

>>1589042
>What is going on?
Them numbers..
Just give it ≈100 torr and all's well.

>>1589042
the datasheet is right, 160 ohms * 7mA = 1.12V. here's a circuit you can use. i think the resistors should be pretty well matched, not just thermally, so the current source shouldn't need to be too precise. otherwise add a third precision resistor in the same configuration as the ref and sense to measure the heating current.

Wait, so if I was using this diode for a flyback converter, would I be limited in the switching frequency I can use?
http://www.vn-experimenty.eu/datasheety/polovodice/2CL77.pdf
Considering my primary inductance is going to be shit-all, I wonder how low my duty-cycle will end up being?

>>1589127
80ns is a tiny fraction of any reasonable flyback frequency so you're fine. if you're the same faggot that's winding his own flyback transformer then just get a core with a higher inductance factor or add more turns so your flyback isn't garbage.

>>1589032
i/o sink source -> +- 40mA each
maximum combined is going to be less than the 200mA max current into Vdd.

>>1589032
>>1589129
i had to look up injection current, its 15mA if you go actively drive an I/O above Vdd or below Vss.

>>1589128
Well I only have 100m of wire for the secondary, so my number of primary turns is limited to no more than 12. Even 12 is pushing it, it's more likely to be 5. But with the better calculations I've done I can probably fit it to a standard long-rod ferrite. Assuming its dielectric strength isn't significantly weaker than air.
I know the reverse recovery time is likely to be fine, or at least not as much of a limiting factor as my FET gate capacitance, but that frequency/current graph threw me off. If it isn't referring to reverse recovery, what does it apply to?

Also how do I figure out what the impedance of my primary will be, since I imagine it will have some dependance on my secondary.

>>1589136
i'm pretty sure that graph is telling you that the maximum average forward current for the diode decreases as frequency increases because of self heating due to the reverse recovery losses. so you could pass ~1.2mA average while operating at 50kHz.

in a flyback your secondary diode is reverse biased while you're charging your primary, so the secondary is open and doesn't count for much. the primary impedance is thus just the coil resistance and Al*N^2. no need to think of it in terms of impedance either really, just use the inductor current formula.

>>1589143
Well that clears things up with regards to the inductance/impedance, but I'm still a bit confused with regards to the maximum frequency. Since it drops of completely at 65kHz, would I be unable to run any current through it above that frequency?

>>1589151
no idea about that honestly. the datasheet doesn't have very many parameters listed so who knows, maybe chang just wanted to make his graph look like the operating curves on all the big western semiconductors.

>>1588928
a farad is 1/3600 amp-hour per volt, that should help you with the math

>>1589151
probably, but I'm guessing the diode won't recover in time to prevent that current from coming right back out the wrong way

>>1589154
But the average reverse recovery time is like 50ns

>>1589157
oh nm

>>1589164
HAHAHAHAHAHAHAHAHAJAHA.

That pic.

But seriously, is this fan supposed to have tons of resistance when it’s turned off? It should spin freely, right?

>>1589185
Not if the switch also brakes it by shorting the windings.

>>1589190
I wish I could remember. It doesn’t feel like regular magnet braking though, you can typically feel the poles where it’s like you’re spinning over humps.

I think the little bearing might be fucked and I’m overthinking any electrical stuff. When I pull out on the shaft hard and try to spin it, there is less resistance.

>>1589185
not if that whole oscillating gear train is in the way

>>1589195
Old grease perhaps? If it still spins fine at speed and it's just a high static coefficient of friction.

If I have two 12bit dacs and an opamp, is it possible to create a 24bit dac from it. The idea being to make the second dac voltage range within 1bit of the first dac and add the voltages together.

>>1589227
you can have a bit less than 24 bits. because of tolerances on the op amp circuit you'll need to have your least significant dac cover slightly more than 1 bit and then work out the gain errors in software.

>>1588928
Oh thanks! I hadn't considered the fact that wall warts usually aren't regulated.
I wasn't planning on using the wall wart anyways, but I'll throw a zener on there just to be safe, should I change my mind or forget.

>Homework
I've already done that. If I did my math right, then:
Energy in the battery: V*Ah*3600 = 3.7 (nominal) * 0.06 *3600 = 799 Joules
Energy in the supercap: (1/2)*C*V^2, but we're not draining it below 2.4v, so 0.5C(V^2 - 2.4^2) = 0.5*1F*(5^2 - 2.4^2) = 9.62 Joules
If 799J keeps the RAM running for 7 days (approx), then (9.62/799)*(7 days* 24 hours) = 2 hours.

Two hours is a lot less than the original spec, but that's ok, because I only need to to keep the RAM live while batteries are being changed.
I could probably increase the time significantly by replacing the old power hungry SRAM with a modern equivalent, but 2 hours is fine by me.
As for why I'm replacing the NiCd with a supercap, rather than a new replacement battery, it's because I'd rather go with something I'm not going to need to replace again, especially when a NiCd's failure mode is to leak acid on the PCB and potentially ruin everything.

Electroniclet here. Bought this wall light online and it came with two wires to set up with existing light fixtures. How do I go about setting it up to be a plug for a wall outlet? Is there an adapter that is made for this type of job?

>>1589255
/ohm/ RULE 0: sparkyshit to /qtddtot/
/ohm/ RULE 1: did you even google "how to wire a lamp"

>>1589255
Aside from this >>1589266, what nation are you in? If in England learning how to wire a plug is taught in schools, and getting hold of a plug made for doing so would be a piece of cake. If it already had a cable it would be a simple matter of buying one of these plugs and wiring it up, but considering those are two single-core wires instead of a double or triple-core wire, and that they're only 3 inches long, you'll likely want to connect that to a few yards of mains cable as well. So either:
>cut the end off an extension cable and match the right wires up
Or:
>buy a few metres of cable and connect a plug to one end and the lamp to the other
The latter is less wasteful, but a little more technical and potentially more expensive. Both require some method for connecting the wires, for which you have a few options, ordered in approximate descending order of how ideal they are:
>Wago lever nuts with ferrules
>Wago lever nuts without ferrules
>linesman solder splice with heat shrink
>terminal block with ferrules
>terminal block without ferrules
>fucking wire nuts
Unless you're an amerimutt, in which case use wire nuts.

>>1589130
>>1589129
Thanks, I was quite overwhelmed with all those terms.

>>1588655
Headers are to install a 1602 module and a rotary encoder. Now I have plenty of each I figured out this is a good time to give them a good use.
I want to expose the copper next to the transistors in order to slap some copper bars on it and minimize the welding circuit resistance.
It's basically a carbon copy of kWeld, but with the components I have in my toolbox and made as an exercise to learn about how to deal with power electronics.

>>1589227
> If I have two 12bit dacs and an opamp, is it possible to create a 24bit dac from it. The idea being to make the second dac voltage range within 1bit of the first dac and add the voltages together.
You can use an op-amp to scale and add voltages. See:
https://en.wikipedia.org/wiki/Operational_amplifier_applications#Summing_amplifier

But the result won't be anywhere near as accurate as an actual 24-bit DAC. If you connect it to a 24-bit counter, the resulting ramp will have definite bumps at the point where the low-order word wraps to zero and the high-order word increments.

>>1589289
Oh that is a neat project. Problem with using it as an exercise to learn about power electronics is that any mistakes will tend to be somewhat expensive.

On a side note, is there any logic towards the naming schemes of IR FETs? I can only assume that the B after IRF means high current, or something along those lines.

>>1589295
>B
die revison. process improvements (purer silicon/dopants, better tuned diffusion conditions, other minor tweaks/corrections) can deliver lower gate charge, lower Rds(on), larger safe operating area, better reliability, etc. from basically the same design
>is there any logic towards the naming schemes
sort of, read a datasheet and sometimes you can find a part # decoder. also e.g IRx9yyy is usually an approximate P-ch complement to IRxyyy, IRLxxx is usually a logic-level equivalent to IRFxxx. there may be a correlation as to die size too but I haven't sorted it

>>1589299
Oh that compliment part is handy.

If my scope says isolated on it, does that mean it is impossible for me to destroy it unless i attach tech ground clamp on the probe to something that has voltage potencical between it ground clamp and probe higher than maximum allowed scope voltage?

Because i have seen people online who literally melted their entire computers with usb scopes because they attached the ground or probe to something that was like 10V but then 100Amps suddenly flew through their poor usb connection somehow

>building guitar effects
>they often use old obsolete parts long superceded by newer, superior parts
>using modern alternatives doesn't always give the same sound
>mfw having to hunt down old overpriced parts
>while dodging all the counterfeit chink shit that is everywhere
fuck
I don't like having to pay 50 cent for a single germanium diode or several dollars for a single germanium transistor when the modern replacements are just a couple of cents.

>>1589125
Shit. idk what i was doing, my math was off.

Shouldnt the resistors be in a wheatstone bridge?

>>1589315
Gotta make your own unique effects with quirks of modern parts instead, anon. Avalanche diodes or MOSFETs or optocouplers.

>>1589319
I will eventually. First up is cloning and maybe modding some old pedals.

>>1589315
"Soviet mil-grade Germanium is best Germanium."
-- <enter your favourite bonamassa here>

>>1589347
>not slapping 2 germanium diodes together to make a transistor

How essential is having a bench power supply when doing microcontroller stuff and making guitar effects?
I mean, it mostly runs at 5V/3.3V and 9V, respectively, so I wonder if getting a variable power supply is worth the the investment. Although it does sound very useful in general to have one. They're just not very cheap is all. Was looking at that Korad KA3005P which seems to not be total shit but that's already €110.

>>1589397
You can just get a basic one, if you don't really need the power or higher voltages. They're already pretty useful and start at 30€.
If you have some unused laptop power bricks or ATX PSU lying around, you can also just use that with some cheap Chinese module.

>>1589397
Waste of money, pull an old wall wart out of the bin instead.
If you get to doing actual analog design/test you might as well jump to a signal generator too

>>1589397
If you have a spare laptop charger lying about, get one of those $1 LM2596-based buck modules for a couple of dollars (the ones with 2 or 3 trimmers) and replace the trimmers with full-size pots. They can handle 3A or so, and can drop the voltage anywhere from the input voltage minus a bit to 1.25V, so perfect to get up to 12V from a 19V laptop supply. The ones with two trimmers have a constant-current mode on them, and the ones with 3 also have a battery charging mode. A digital current/voltage readout for $2 or so would be good too, but you'd need one that can have a voltage vary from 19V to 0V.
Links:
https://www.aliexpress.com/item/buck/32580214850.html
https://www.aliexpress.com/item/meter/32824062417.html
From experience I can tell you that the trimpots are two 10k and one 100k, which you can also read off the top of the trimmers on the listing. I'd also get a box and the appropriate barrel socket for the laptop charger. Maybe even get two of the meters and buck modules because they're cheap to make a 2-channel supply, though I'm not sure if you'd be able to make an effective split-supply like you might want for audio purposes; i.e. whether you can sink current into an output.

The cheap ATX + chink module is also a decent option.

>>1589289
How did you divide your schematic into sections? Looks neat.

>>1589409
How's the ripple on those things?

>>1589418
I never measured it, but you can probably check the datasheet for the IC for most of what you'd need to know. Could always add bigger output caps.

>>1589397
not very. for years I used a triple-output brick I bought at surplus, before I found the magical buck modules were so cheap

>>1589412
not them but they used the line tool (dotted line square in the right side toolbar)

>>1589289
are you gonna use TIM1's quadrature counter to decode the rotary encoder?

>>1589409
probably less than the typical 60Hz ac wall-wart. you can always add more capacitance until it meets your standard

>>1589409
>>1589419
>>1589420
Alright cool, time to order some chink shit again.
I love getting cheap shit like this that's actually useful.

>>1589422
So you have a laptop charger lying about? Neato.

>>1589365

>>1588105
It looks like an input board without the brain. (just passive elements)

You more hardware to use that.

>>1589463
It has a few trannies.
What active circuitry do you need for an equalizer except for input buffering and gain?

>>1589246
>Homework
Very good, thank you. I used a different approach and simply compared the stored charge. The result is very similar. The NiCd stores about 200As and the cap holds 1F(4.5V-2.5V)=2As. 2.5V because of D301 and the 2..4 V requirement for VB during back-up. For 5 days (max RAM) I got 1.2h and for 15 days (min RAM) it is 3.6h, obviously. Also, a new set of AA cells has more than 6V and a Z4V7 diode would be optimal, despite D12. Image is from the Tandy 200 Owner's Manual, 1984.

Getting in to /ohm/ stuff recently. Need to get a multimeter. How chinkshit can i go before its useless garbage?

>>1589471
Uni-T is generally acceptable I think. Wouldn't use it to measure mains or high voltage but for small electronics they're fine.

>>1589464
output buffering maybe
I think it'll work as long as you feed it the power it expects

>>1589471
get you an AN8009 for $25. it's a better first meter than the poor old B+K I've had for nigh on 30 years (but the Aneng may not last quite as long)

>>1589473
>Wouldn't use it to measure mains
Every Uni-T teardown I've seen confirms their specified ratings. I don't see a problem with using it for mains.

If I need to power some opamps with negative and positive voltage, can I just take two 9v batteries and wire one in backwards?

>>1589501
sure, it's called a split supply

>>1589502
This makes a lot of sense, thanks

>>1589501
>backwards
almost!

>>1589289
>rotary encoder
Did you catch the Bourns encoder fiasco Frank was blogging about?

Came up with a working prototype of my miniature lighthouse flasher circuit. It will have a 6 V/2 W light bulb inside the lantern that flashes every 16 seconds and 4 red + 4 green LEDs around the tower that alternate every five seconds or so.

>>1589582
Schematic of the gadget. It's currently only missing the 7805 regulator that I used in the prototype.

>>1589271
Thanks for this. Going to try the first method

>>1589585
Congrats, it works!

>>1589601
Thanks Anon, now I'm just wondering if I could fit all the components on a 5*7 cm perf board.

>>1589614
Maybe you could stack two boards if need be, or even three.

>>1589317
you can if you want, but you already have the heater current source acting as an R to V conversion

in other news i'm going to self immolate in front of google HQ to protest their captcha bullshit

How do nerves work without semiconductors?

>>1589295
>any mistakes will tend to be somewhat expensive.
Yeah, I already blew up a bunch of MOSFETs. Fortunately these aren't too expensive if you buy it from Aliexpress and get the job done. There is always the possibility that they are selling me some lower capacity MOSFETs, but I'm willing to take the risk.
>>1589412
Just used the line and text tools. In KiCAD you can subdivide the sheets as black boxes but I think it's unpractical. It was difficult to cram everything together in just one page.
>>1589420
Didn't think of that. I thought about merely using a software solution, but I'm going to take a look. Thanks for the advice.
>>1589533
No, but I'll check that out. I'm just using one of these chink modules as they will save me some montage troubles and space in buttons.

>>1589789
What's the deal with those 4 big square pads?

>build a buck converter
>noisy asf at >1A
>not switching noise, more like static
>turn it on again, start hearing weird sounds
>mfw it's actually music
>somehow it's picking up radio
Guess I shouldn't have used wire wrap on all those control parts I was too lazy to solder

>>1589790
A current limited step-down module to charge the capacitors based in LM2596, pic related. I know it's a cumbersome method, but I didn't feel like bothering with charge balancers for the supercap system. The circuit is made mostly with materials I already have in my toolbox.

>>1589795
Based lm2596.

>>1589793
Wire-wrap shouldn't be making non-ohmic schottky junctions for demodulation if you do it properly. At least I think that's what causes the demodulation. Could be using a diode in your circuit otherwise, but I find it hard to believe you're receiving sufficient a signal amplitude to surpass the forward voltage of any simple diode modulator.

>>1589797
I was wrong, it seems that the inductor is acting as the loudspeaker, not the mosfet, which probably means that the banana plugs (~1m) are acting as the antenna, not the wire wrapped cables, and that the flywheel diode is acting as the demodulator. Interesting.

>>1589804
>not using toroidals

also fuck you i can't build a regular crystal radio and hear anything from it after buying a germanium diode and crystal earpiece and spending 2 hours winding and rewinding an antenna, how the hell did you do so in a fucking buck converter

>>1589805
Do you have any strong AM stations near you?
I built a crystal radio, and it only picks up like two stations: A christian talk show and Mariachi.

>>1589824
I think I have some stations nearby, I'm in the middle of a large city and I think I checked online last time I was messing about with radio and saw a fair few stations locally, but I find it very difficult to actually find a source that tells me what amplitude they're transmitting at. Best I could to was look at an FM channel and assume they had the same order of magnitude amplitude. Then I tried to use that to calculate the amount of magnetic flux going through my antenna and subsequently figure out the induced EMF, which didn't work out at all.

>>1589464
>>1589789
>tfw "blew a tranny" means something completely different outside of electronics

>>1589793
kek
>wire wrap
laughingsluts.jpg

>>1589804
remember, the MOSFET is basically a capacitor. is your gate being pulled both high and low with a low impedance? (4k7 pullups aren't going to cut it)

>>1589828
a hole's a hole
t.semiconductor scientist

>>1589473
>>1589474
Found this thing on a local usedstuff site for cheaper than a Uni-T or Aneng. Would it be usable for microcontrollers/general computer-y stuff?

>>1589850
Certainly, provided it has a battery and fuse installed, and actually turns on. But how much is it going for? It's more valuable as an antique than as a functional DMM, so if the price goes above ~$35 I personally wouldn't buy it. Look up its specs and compare them to the aneng, should give you some idea of what you should value it at. It's also likely missing a few convenience features modern DMMs sometimes have, like alerting you when the probes are in the wrong way around, auto-turn-off, backlights, etc. and the 2A current limit isn't too high.

>>1589861
He's asking $20 and says its been "professionally calibrated" recently, whatever that means.
Comes with the original manuals and shit too. No idea if it actually turns on, but he doesnt say it wont.

>>1589862
I'd say that's a pretty good buy, though I'd wait for another anon or two to say their thoughts on it since I'm not exactly an expert on DMMs. I skipped right from the $5 bracket to the $250 bracket.

>>1589862
I would buy it. It's a 10MΩ meter and it has excellent documentation, including instructions on how to recalibrate it against a trusted reference. It seemingly has no backlight and no continuity beep. Everyone needs more than one meter. Next buy one of these Aneng multicrap meters and observe which one you will mostly use. Pic: That's how it should be.

>>1589893
$250 DMM anon here, also considering getting an Aneng as my second meter (especially since the Hioki doesn't do mA), but for now I'll hold off on the more expensive online orders due to my precarious shipping situation.

>>1589896
>Hioki doesn't do mA
AFAIK all Anengs after the 8002 have a current mode resolution gap:
Range--Resolution--DC accuracy--AC accuracy
99.99µA--10nA--±0.8%+3--±1%+3
999.9µA--0.1µA--±0.8%+3--±1%+3 <--
999.9mA--0.1mA--±1%+3--±1.2%+3 <--
9.999A--1mA--±1%+3--±1.2%+3
Also, the R mode limit is <10MΩ, the 8002 does 60MΩ.
The site I got that from (www.markhennessy.co.uk/budget_multimeters) doesn't seem to respond, but you can still read the google cache.
Personally, I rarely measure current directly and prefer cheap 1% lowΩ SMD shunts I can implant as test points in the prototype design.

>>1589930
My Hioki already does 60MΩ, and that current resolution gap doesn't look too much of an issue. Worst case I'd be measuring 1mA to ±0.1mA precision, which isn't exactly stellar, but it's good enough for most of what I'd be doing. Measuring down to the 3rd significant figure isn't of much importance when you're not dealing with precision parts, and if I did want more precision I would just use a shunt with my Hioki's mV range. Not that I have much of a collection, just a couple of surprisingly expensive 10mΩ THT shunts that I bought (like most of my collection) for a project I eventually thought better of. Let's hope the 10 pack of 20kV silicon stack diodes and 100m of 0.2mm enamel wire don't go the same way.

For measuring 1mA-100mA a 100Ω-1Ω ordinary 1% THT resistor would work fine anyhow. I'm not too savvy when it comes to fabbing PCBs just yet. But I've ordered some THT rivets, so that could change soon.

Does the EEVBlog forum's spreadsheet not have Anengs on it?

>>1589582

that's the least realistic lighthouse ever. and there's no excuse for it coz there are ''literally'' gazillions of circuits in the ''light chaser'' ''knight-rider'' or ''Larson scanner'' category available on the inter-webs.

>>1589958
I think his excuse is no MCU

>>1589893
>>1589866
Thanks for the advice, but i'm gonna go for something else. No continuity is a bit of a dealbreaker and besides, its too historical for a newbie like me. I wouldn't appreciate it.

>>1589966
Fair enough.

Any advice?
>>1590031
>>1590032
>>1590035
>>1590037

>>1590039
So where can I probe to see if the thing is getting the right power?

>>1590049
The outer magnet and the copper coils should probe at 120v?

>>1590039
check fuse

I am fucking up my calculations here,
so esp32 in deep sleep consumes 10ua
So that would mean that in deep sleep i could run it from a single aa battery witth 1.5ah capacity for 171 years. that can't be right, right?
1.5 / (365*24*0.000001) = 171

>>1590136
I get 17 years. But anyhow Ah ratings are pretty meaningless unless you know the rate that was tested at and it would die on its own either way.

>>1590145
Not to mention a single AA wouldn't give you enough voltage and a boost converter would imply taking more current from the battery because of conservation of energy + losses.

>>1590146
Well it's fucked anyway. I timed it and connecting to a wifi and sending a quick request before going to sleep takes about 8 seconds, so even if i send the pulses every 5 minutes that is still 0.6h of up time per day, in active mode the module pulls 200ma, so that is 43AH per year. That is literally one lead acid car battery worth of capacity.
How the fuck do shits like smart wall mounted wifi thermostats run on 3AA batteries for a year.

The only solution here would be to massively reduce pulse frequency to like once per 30 mins and use some big lipo ballsack to power it, but that makes the device pretty useless in things like thermostat applications.

>>1590120
Es no fuse!

There is one in the plug like xmas lights have and that thing is good.

>>1590159
they take their power from the furnace, of course

>>1590163
Do the LEDs come up?
Do the triacs trigger?
What's that IC you flashed on?

>>1590177
Voltage across ZD1?

is it possible to buy an extender ribbon to make this chink tablet camera extend a few feet away from the tablet? I googled the markings on the cable but I came up with nothing. All I know is its 18 pins but I also know there are different sizes so im lost as fuck. How can I identify the cable type? Do extenders for this kind of thing exist?

>>1590177
Yeah LEDs and buttons all work fine

Where was LD1?

Motor doesn’t even hum or anything. Can’t tell any difference in resistance with the motor off or L-M-H

>>1590327
thats called a flat flex cable or FFC.
Figure out the pitch and pin count and either buy the matching connector and roll a pcb adapter or buy something like this

>>1590177
>>1590189
Also I tried to see if the oscillating feature would still work because it looks like it’s another motor, but that doesn’t go either.

I should be getting 120V at the motor somewhere, right?

And if by “IC” you mean pic related, that bitch is blank.

>>1590177
>>1590189
I was also retarded here >>1590039

That 14V was me being stupid. Black down in the corner was neutral. I get ~120V across N1/ACN and L-M-H-Osc coming from the board when it’ on the correct setting.

>>1590376
that's some really bad solder masking

>>1590390
It worked... for awhile

Update- I still don’t understand what all these things do, but I found a thermal fuse

I wish I could see where the 5 wires going to the motor actually terminate and go off to the oscillating motor, but shit is covered and paper and all glued up.

So where does the black (ACN) go to when running a motor like that?

>>1590396
Yup, fuse. Now I decide whether to hotwire it and burn the house down, wait 6 weeks for China to send me a 5pk, or find an assortment on Amazon Prime

>>1590396
If you draw a diagram of the circuit, especially the wires going in and out of the motor. The thicker wires will be current-carrying, and the thinner wires will be sense wires for thermistors or the like. To be honest I'm not even sure what sort of motor it is.

>>1590425
I guess it's blown? Nothing wrong with shorting it for testing purposes. The wires to it look too thin to be current-carrying, sure it's not a sensor?

>be me
>learn how to measure output impedance of amplifer
>new multimeter.wav
>plug in numbers
>12 ohms
> wait, this is supposed to have 10 ohms, theres a 10 ohm resistor in there.. does the chip have a 2 ohm resistance?
> open it up
>poke around
>stops working
>amp chip is super hot
>tfw i thought all the pins were high z

>>1590429
It’s a thermal fuse, I googled it. I bypassed it and it worked.

Was surprised at how thin it was too compared to the other wires, but it looked like it broke the neutral for the fan and oscillator so does that make sense?

Found new ones on Amazon, 10pk shipped for $7. They’re not exactly the same brand but everything looks super similar. 250V 2A 130C but the datasheet for originals says 0.6mmx0,6mm and rhe replacement is like 0.56mm

>>1590429
>>1590449
I ordered this. I was hoping to find an assortment just to have them around for random repair but didn’t see anything good on Prime. Pic related was the original, the A4-F

10Pcs New RH 130C Double Lead Temperature Control Thermal Fuse 250V 2A https://www.amazon.com/dp/B011HFOPS4/ref=cm_sw_r_cp_api_i_l2PRCb4W2RHFT

>>1590457
I guess it was acting as a sense line, instead of breaking the circuit of the motor proper. Perhaps they don't like working in series with inductive loads or something.

>>1590159
> How the fuck do shits like smart wall mounted wifi thermostats run on 3AA batteries for a year.
By not taking 8 seconds to send a packet. Most such devices uses Zigbee rather than BlueTooth or WiFi.

>>1590449
>does that make sense?
I think it does. It's an typical induction motor with windings for different speeds (L,M,H) and a running capacitor of 3µF mounted on the motor and connected to the GREY/YELLOW wires. The small thermofuse is shown in the wiring diagram leading to the BLACK(N) connection. The second smaller motor is for the right-left motion of the fan (OSC.R/L).
All action is controlled by a set of four SMD triacs (TR1...TR4) on the board that go to the motor wires. The red cap with 155J400V on it along with D1,D2 and the white 39Ω series resistor seems to be a transformerless supply circuit for the control board that was once meant to be protected by the fuse F1 (now shorted) connecting to ACL.

>>1590610
>2-phase
>windings for different speeds
Ah that's why it had so many wires. Pretty small looking for a run capcitor, but whatever. Though it's odd to have the thermal fuse being in series with just one winding.

>>1590623
>in series with just one winding
It's the common N for all windings.

>>1590623
There is a big cap up near the motor, you can see it in this pic >>1590396 top left, it’s a white case with like black epoxy type crap filling it.

>>1590644
>>1590647
oh right, thanks

>>1590647
That should be the running cap. Does it have any markings on it?

I'm looking for a replacement for an AN6610. Obviously I could go just for an NOS from China, but I'd like a currently in production part. Any ideas?

>>1590725
https://lcsc.com/product-detail/Motor-Drivers_AN6652L-T6B-K_C75530.html

Any way to unbridge these connections without damaging the PCB any further?

>>1590793
solder wick, obvs

>>1590802
Should I use that in conjunction with some extra flux and/or tin? I'm worried about it removing the tin that was on the PCB to begin with.

>>1590807
add flux to board and wick
apply heat to solder blob THROUGH the wick
and slurp
>tin
you can always add tin back. copper is a bit harder to add back

I have these. Can I use just a PSU, resistor and a relay in order to make a CD welder? I also have a dial voltmeter. I can do this without any microcontroller, right?

>>1590829
>I have junk, what do?
sure. you'll weld the contacts on your relay and we'll laugh at you
go look up proven designs because clearly you aren't at a level where you can do it yourself

>>1590829
No resistor, no relay. Wire the caps in parallel, charge them to 75V and short them with two wires. Discharging caps is always fun.

>>1590869
>Discharging caps is always fun
Not when you melt your screwdriver.

>>1590660
Now that I’m home with no stupid mobile IP ban...

I forget exactly what that fuse was connected to. I don’t want to break off any of those little copper windings connected to the 3 speed control wires so I’m not trying to take it apart again until I have the new fuse.

I think that fuse was between the black ACN wire coming from the board and the grey wire. Then what is the yellow? Is yellow the N going back to motor? Or what the hell does N do with a motor like that? And what does that big cap do? AC confuses me.

>>1590736
Dang, thanks!
Not to be picky, but is there one I could pick up Digikey/Mouser/et. all?

>>1590990
See pic.
>between the black ACN .. and the grey wire
Correct. TF is the thermofuse.
>Then what is the yellow?
The 3µF cap is between grey and yellow, and yellow then has the phase-shifted voltage producing the rotating magnetic field that turns the rotor.

>>1590854
I've seen someone on Youtube using a relay. Yeah I know relay contacts can melt together. Plus this is not junk, the capacitors have never been used.

>>1590869
The wire would explode

>>1590961
Why not? You got what you wanted.
Context was 20Ws btw.

>>1591009
>wire would explode
exactly, that's the fun.

>>1590990
>mobile IP ban
Oddly enough I've got a desktop IP range ban but no such ban on my phone when it's on the same network.

>>1591010
>Ws

>>1591004
I don't see anything good, my dude
looks like you might have to crib from the internal diagrams of one of the chink drivers. Rohm and Sanyo were active in the dc motor speed governor space, and might have something worth copying

>>1>>1591036
5>>1591036
91036
>>1>>1591036
>>159>>1591036
>>1591036
1036
>>159>>1591036
1036
>>159>>1591036
1036
591036
>>1591036
>>1591036

>>1591017
I bought a couple passes before but now I refuse because I think Mook is a joo. Since he took over, that mobile ban comes around every 12-14 months just as the old pass expires, and then it seems to go away. The captchas do get annoying, but why am I gonna give you $20 after you gave me ads and 4channel?

>>1591007
Hmmm ok I still don’t really understand AC or neutral, but then again I didn’t know how to use a multimeter a year or two ago. Now I know how to use one or two functions on the meter!

But the 3 different power levels, is that like 3-phase power? So when M is turned on, power will be coming through L and M with those offset waves?

>>1591039
I still buy a pass because I've grown dependant on not solving captchas.

>>1591039

>>1586435
>€300 on parts
How the actual fuck? Don't tell me you paid >$5 for an IC, or >$3 for each knob, and still didn't figure a cheap iron/prototype board in there

>>1588105
Noob here
When separating a signal into multiple bands, am I right in thinking you can't simply short the outputs together to recombine them? In that case, are those differential amplifiers mixing the bands together at the base?

Are they then compared to the input signal?