/ohm/

[Anonymous No.1816800]

died thread: >>1807118

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

>Project ideas:
http://adafruit.com
http://instructables.com/tag/type-id/category-technology/
http://makezine.com/category/electronics/
Don't ask, roll:
https://github.com/Rocheez/4chan-electronics-challenges/blob/master/list-of-challenges.png.png (embed) (embed)

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

>Design/verification tools:
LTSpice
MicroCap
falstad.com/circuit/circuitjs.html
NI Multisim
CircuitLab
iCircuit for Macs
KiCAD (PCB layout software, v5+ recommended)

>Components/equipment:
Mouser, Digi-Key, Arrow, Newark, LCSC (global)
RS Components (Europe)
eBay/AliExpress sellers, for component assortments/sample kits (caveat emptor)
Local independent electronics distributors
ladyada.net/library/procure/hobbyist.html

>Related YouTube channels:
mjlorton
w2aew
jkgamm041
eevblog
EcProjects
greatscottlab
Photonvids
sdgelectronics
BigClive

>Li+/LiPo batteries
Read this first: http://www.elteconline.com/download/pdf/SAFT-RIC-LI-ION-Safety-Recommendations.pdf
>I have junk, what do?
If you have to ask, nothing. Get rid of it.

[Anonymous No.1816841]

Protip: when looking for components use octoparts.com .

[Anonymous No.1816867]

>>1816800
Suggesting again to add a section for board making services.

[Anonymous No.1816869]

>>1816867
Dudebro everyone under the sun knows about pcbways

[Anonymous No.1816871]

>>1816800

That's an odd looking kitchen...

[Anonymous No.1816878]

I know its a long shot, but is there any way to identify this 8mp camera module?
A prominent laser cutting software for chink laser cutters sold them as compatible with the software, with software built especially for it.
They are out of stock and they said they arent getting in more anytime soon.

People figured out their old 5mp camera module just by looks, could just buy it right from china. Nobody knows about this one though.

[Anonymous No.1816881]

>>1816878

[Anonymous No.1816950]

>>1816841
no!

[Anonymous No.1816957]

>>1816878
Probably something with an OnSemi AR1335 sensor based on those specs.

[Anonymous No.1816987]

I salvaged a bunch of cable that has two cores and a twisted wire shield (kinda like pic but it has two cores instead of one). Is there anything wrong with using the twisted shield for power delivery? I'm thinking about using the shield as a negative lead and two cores as a positive lead for a 12V or 24V power delivery.

[Anonymous No.1817010]

>>1816987
>using the shield as a negative lead and two cores as a positive lead for a 12V or 24V

that's the way it's usually done. this assumes the wires are thick enough. the main use case for dual shielded cable is for audio, not for power.

[Anonymous No.1817040]

>>1816800
>man hands
that ain't no woman!

[Anonymous No.1817043]

>>1817010
>that's the way it's usually done. this assumes the wires are thick enough. the main use case for dual shielded cable is for audio, not for power.
Cool. Thanks anon.

[Anonymous No.1817087]

>>1816800
Where’s the best place to get a good transformer for cheap? A lot of the ones I see online just seem overpriced

[Anonymous No.1817155]

>>1817087
probably cybertron

[Anonymous No.1817300]

How can i learn to repair old console hardware? What are some things i need in my head or documentation of the hardware books.

5th 6th 7th generation hardware but also mobile stuff like GBAs and cartridges

Anyone know? Aside from nand2tetris i dont know much about hardware

[Anonymous No.1817384]

>Sony Tektronix 336
>sold for fiddy bucks
>described with a generic "needs repair"
Is it possible to learn and repair it with just a DMM, or is it a can of worms?

[Anonymous No.1817397]

>>1816800
God i wish that was me

[Anonymous No.1817408]

>>1817300
>How can i learn to repair old console hardware?

there's a youtube guy that does videos with titles like ''I Bought 44 Broken Handheld Game Consoles from eBay - Can I Fix Them?'' what you get from the videos is that the same problems crop up quite often, so if you learn a few tricks, you can fix a lot of 'em. you also get a sense of how much money you can make from it, which isnt much.

>>1817087
Where’s the best place to get a good transformer for cheap?

the thrift store. an old mini-stereo, for example, a heavy one with a linear supply, goes for $8 but comes with a powerful 100W transfomer with multiple voltages. a clock radio, or a computer speaker for $3, might come with some 9-12V transformers at about 1/2-amp. of course, there are also individual chargers you can take apart for a buck or two, but only get the heavy (linear) ones.

[Anonymous No.1817429]

>>1817408
So i gotta buy a book on ttl and fix together scrap?

[Anonymous No.1817431]

>>1817384
Could be an easy fix like replacing a fuse, could be a $500 fix. No way of knowing. For that price it's maybe worth a shot though. I'd ask some questions on the listing as to what about it doesn't work.

[Anonymous No.1817458]

>>1817429
>So i gotta buy a book on ttl

TTL? only if you're going way way back to the 80's and 90's. newer stuff is all custom chips. and you dont buy databooks, coz every chip has PDFs you can google. a youtuber whose videos you might search is ''The 8-Bit Guy'' coz he does some repairs and upgrades for stuff for that era.

[Anonymous No.1817464]

>>1817458
That stuff still uses cmos which is basiclaly ttl

I gotta gwt databooks i like to have physical text with me when i do things rather than look over wta monitor constantly

[Anonymous No.1817490]

where to solder my wire directly on pic related?

after quick google search, when barrel jack is inserted, it's suppose to short the insertion detection thus, the device use the external power instead of using battery.

red is 5 volt and black is ground.

[Anonymous No.1817515]

>>1817397
>arrive at worksite
>spend 30 minutes wiring up stuff
>spend the next 7 hours and 30 minutes by getting triple penetrated by thirsty old bald fat smelly tradesmen
sounds terrible

[Anonymous No.1817529]

>>1817490
Short it to GND I'm guessing, as the trace going off the detection pin goes to a resistor and then to a via (not to the ground plane), which I assume is going to Vcc. This makes sense if the socket's switch is an NO from detection pin to sleeve. By shorting this pin to ground you make the circuitry think that it's always plugged in via the barrel jack. I assume this will have the effect of enabling the switching converter constantly, but I'm a little concerned at those unpopulated pads, especially that 8-pin IC that could easily be a switching controller, and that diode that's consistent with a buck converter's freewheel diode. But it's hard to tell because of the silkscreen and reflections making the traces hard to distinguish. To the best of my abilities it looks like the inductor (and diode) are directly connected to the tip, which doesn't line up with a standard buck topology.

[Anonymous No.1817537]

>>1817529

[Anonymous No.1817544]

I have a situation where I need to determine with a micro controller weather or not a switch has been activated. I only have access to the switch and have no ground reference.
What is the best way to go about this?
Pic related.

[Anonymous No.1817548]

>>1817544
measure voltage drop across the switch, low side to the chip ground, high side to an analog pin
make sure the power source for the micro is floating or you will fry it
safer way is to use hall effect sensor to measure the current in the wire

[Anonymous No.1817550]

>>1817515
what are fat smelly tradesmen doing at my jobsite
I only work for chads with hot wives i can lesbian with

[Anonymous No.1817566]

>>1817548
Cheers

[Anonymous No.1817602]

>>1817544
>Switch closes
>5V goes to Q2
Unless I'm missing something here, shouldn't it be that simple?

[Anonymous No.1817664]

Question:

I have two Porter Cable 20v batteries that are registering as "broken" by the charger and won't take a charge.

I watched a few YouTube videos that suggested the batteries can be drained so low they fall below the threshold of what the charger considers a functional battery, and they just need to be jumpstarted a little. I tried the "running some wires from a live battery" trick a few suggested, but I couldn't get either to charge. Today I picked up a HF multimeter and both are showing 17/18 volts.

Any idea how to fix these? Sorry for my poor understanding of electronics, I haven't done anything related since high school.

[Anonymous No.1817697]

>>1816987
My laptop charger has this cable

[Anonymous No.1817707]

How can I blow up an analog oscilloscope?
I want to accomplish two things. First - make uni buy new shit (and thus reduce salary of professor I don't like). Second - get myself an oscilloscope for free from trash.

I don't really know how to blow it up.
If I blow up power supply of it (i.e. exceed voltage rating of all caps inside), I think I can repair it easily afterwards, but this will be pretty obvious, since those caps will produce a lot of smoke, and they will make me pay probably.
Second, blow up the input part of scope with some REALLY high voltage (because 50 MOhm input impedance). This would be harder to repair I think, but it would be pretty stealth I think, since you don't need high current high voltage power supply.

Also, is it ethical to steal parts from uni?

[Anonymous No.1817709]

dont do it Jamal

[Anonymous No.1817724]

>>1817709
I'm not Jamal. I'm Vadim blyat.
Last time I did this I won a multimeter. I measured current in electrical socket, shitted my pants... Then I found this multimeter in trash, picked it up, replaced the fuse and shit works. I have no idea why didn't they change the fuse.

Also, I'm the guy who steal the screws from everything...

[Anonymous No.1817725]

>>1817602
OP said they are missing a ground reference which implies it's not that simple.

If you don't have the same reference (usually ground), you cannot be sure you'll get the same measurement.

[Anonymous No.1817726]

>>1817707
connect ground clamp to live wire in the outlet

[Anonymous No.1817728]

>>1817707
>Also, is it ethical to steal parts from uni?
Depends on how high the tuition fees are.

[Anonymous No.1817730]

>>1817726
If building has proper ground (i've doubts), it will trip RCD/GFCI and/or CB. It won't damage anything.
If building has no ground, I will make a hot scope. It is fun only if you do this to professor's scope.

[Anonymous No.1817734]

>>1817730
current protection is only used for bathrooms, if you connect ground clamp to live wire in the outlet it will instantly blow the scope
just try it tyrone

[Anonymous No.1817737]

>>1817734
Dude, I'm not Tyrone, I know thing or two about wiring. CBs are everywhere, and RCDs are mandatory on all circuits since whatever year.

[Anonymous No.1817738]

>>1817707
>Also, is it ethical to steal parts from uni?
Is your education system run by the state? If it is, then it's unethical since you're stealing from the community, however if your uni is a private institution whose sole purpose is to turn a profit by exploiting a human right and a need of a free society (education), than get whatever you can and run away to a more civil country.

[Anonymous No.1817739]

>>1817738
>from the community,
all the equipment was purchased from my taxes, so i am simply taking back whats already mine

[Anonymous No.1817741]

>>1817739
Your taxes alone?

[Anonymous No.1817743]

>>1817738
>Is your education system run by the state?
No, I pay for everything, but fees are too high for quality of education, so I must somehow compensate.
>If it is, then it's unethical since you're stealing from the community
Still no, since I (my parents) would have paid taxes™, so shit belongs to me.

[Anonymous No.1817744]

>>1817739
That's not how it works anon. Beside, taxes are for the community: those who came before you left something for you to benefit, and if you leave the place a bit better than how you found it, then civilization progresses for the benefit of everyone. If instead you think selfishly, then you not only steal from your peers, but also from the future generations. This doesn't apply if said institution is purpusely purpusely turning a profit, since they're too stealing from the future of society.

[Anonymous No.1817746]

>>1817744
Taxation is a theft. So stealing part is getting your money back.

[Anonymous No.1817749]

>>1817744
>those who came before you left something for you to benefit,
it doesn't count if they were forced to.
make taxes optional and then we can talk
if gov can steal from me i can steal from them

[Anonymous No.1817761]

>>1817743
>I (my parents) would have paid taxes™, so shit belongs to me.
>>1817746
>Taxation is a theft. So stealing part is getting your money back.
>>1817749
>if gov can steal from me i can steal from them
What a nigger-tier take.

Total up all the taxes that your parents have paid to whatever government funds the school. Then, figure out what percentage of the budget is spent on university education. Take that percentage of your parents total taxes paid - that's how much they've "paid" for you to go to school.
Now, find the per-student cost of the school - essentially the schools annual budget + any extra tax money they've spent (e.g. for a new building). Subtract the per student cost from the total education taxes your parents have paid. The difference is how much you can "ethically" take.

You'll probably find that number to be a negative. Unless your parents are in the top 10% to 1% of taxpayers, your education is being subsidized by the wealthy people of your country.
If you really want to make things "fair", you would cut your government a massive check for the services that you've paid a discount price for.

[Anonymous No.1817771]

>>1817761
The middle class pays the vast majority of the country's taxes.

Even though wealthy people pay more individually they are hopelessly outnumbered.

[Anonymous No.1817773]

>>1816800
Not the best PPE on a site at all.

[Anonymous No.1817804]

>>1817761
Imagine believing this shit.
Stealing parts is ethical as fuck and legit form to recoup tax money

[Anonymous No.1817838]

I see a Tektronix TDS2012 scope for about $120. Need my first scope. It works. Jump on it Y/N?

[Anonymous No.1817849]

>>1817804
>recoup tax money
You "recoup" tax money by using roads and sending your children to school, or calling the fire department or the police.

[Anonymous No.1817860]

>>1817458
>>1817429
don't watch 8 bit guy he doesn't know anything about hardware. good programmer but his restoration vids are shit.

if you're interested in fixing vintage consoles, i would recommend Mr. Carlson's Lab for a good way to learn about how to work through repair problems. For more applied things, check out Ben Heck Hacks. He used to be a big modder, but he's incredibly knowledgeable about older game systems and electronics.

Best way to get in is to just get your feet wet. Buy a broken NES off CL, and start tinkering around inside and learning how circuits interact with each other and the cart and the CPU.

[Anonymous No.1817862]

>>1817464
>>1817429
also you don't really need to know too much about TTL or CMOS or any of the fabrication nodes. You just need to know how they work, which isn't fab-specific. Look up part numbers to find out what it does, what the pins are, and how you can re-route things if you need.

[Anonymous No.1817866]

>>1817707
don't blow it up. open it when nobody is looking and just pull a connector on the inside- nobody in academia will ever open an oscilloscope up so you can safe bet they'll just dump it.

[Anonymous No.1817868]

>>1817707
also blowing up the input stage is not always a trivial repair.

stealing from uni is ethical uwu i took a curve tracer

[Anonymous No.1817870]

>>1817838
honestly unless you really need to save pics of waveforms i would pass. low bandwidth and sample speed, for that price you can probably get a better analog scope

althought for digital, that doesn't matter. if you're not doing analog work, this is a fine scope.

[Anonymous No.1817877]

>>1817870
I intend to use it for MCU centric work and some hobby experimentation with video and other computer related signals (see "the world's worst graphics card" on youtube, which I intend to replicate).

[Anonymous No.1817887]

>>1817877
You'd be better off with a cheap logic analyzer.

[Anonymous No.1817888]

>>1817849
How do I recoup money by using roads, when I pay arbitrary car tax, or when I pay arbitrary property tax and arbitrary VAT and whatever.
Literally, unless you're hobo you pay pretty much for everything. Btw, I'd prefer toll roads everywhere over shitty unmaintained taxpayer roads, paid schools and shit.
>>1817866
Thing is, this is plan for future, since during corona only thing I can break is my shitbox.
I think it is a good idea to replace fuse with blow one or something. But I've no idea if fuse is easily accessible. (because I don't even know exact model).
>nobody in academia will ever open an oscilloscope up so you can safe bet they'll just dump it.
This is a good thing.
>>1817868
>also blowing up the input stage is not always a trivial repair
True. Maybe silently short the BNC jack?

[Anonymous No.1817891]

>>1817887
Before I run up that tree, I found a working OS-5060a for $40. Worth the effort or no?

[Anonymous No.1817911]

>>1816800
Are CRT circuits /ohm/?

I have this old iMac. When it powers up, you can hear a kind of snapping coming from the PSU/CRT area, and the screen will flicker whenever it snaps. Sometimes it will snap and the whole system will shut off.

I know CRTs are bad news, but they are supposedly self-discharing in imacs. but to be safe I have left the computer unplugged all morning.

Some people say the horizontal output transistor might be bad (https://68kmla.org/forums/index.php?/topic/30534-imac-g3-wont-power-on/)), If its just a case of replacing a component, I can do that no problem.
I was going to sell it anyways but I figured it would be worth more if it was actually working instead of trying to sell it broken

[Anonymous No.1817920]

>>1817868
Where are you from?

[Anonymous No.1817942]

I want to make a bluetooth keyboard of sorts but it only does two things: copies and pastes from clipboard. What would be the best route for this? I'd like it to be two buttons, copy, and paste.

[Anonymous No.1817971]

>>1817911
I guess it wasnt quite it, seems more like failed Flyback transformer..

>It used to do what I call "ticking" - the picture would flicker momentarily, accompanied by a high voltage arcing sound. It started out as a rare occurrence, but over time got so frequent the machine would start crashing and restarting from what I can assume was the flyback drawing excessive current from the power supply. This appears to be quite the common failure in the Molar, as well as in the iMac G3, various CRT Studio Monitors and a few other CRT-based Apple products from the same time period. The failure apparently occurs in one of the internal windings, as the bad flyback appears cosmetically perfect with no cracking or other physical signs of failure.

[Anonymous No.1818022]

>>1817942

use a utility like keytweak. assign F1, or whatever, to CTRL-C and F2 to CTRL-V.

possibly a better idea would be to get a mouse with 2 extra thumb switches you can program. if you're dexterous, that is.

[Anonymous No.1818055]

>>1817771
https://taxfoundation.org/summary-latest-federal-income-tax-data-2018-update/
>The top 1 percent paid a greater share of individual income taxes (37.3 percent) than the bottom 90 percent combined (30.5 percent).
From that we can infer that the total top 10% of taxpayers account for 69.5% of all the money the federal government collects. It goes on to state:
>In 2016, the top 50 percent of all taxpayers paid 97 percent of all individual income taxes, while the bottom 50 percent paid the remaining 3 percent.
That's the USA - a country that is notoriously easy on rich people.

>>1817804
>Imagine believing this shit.
>Stealing parts is ethical as fuck and legit form to recoup tax money
Just because you say something is ethical, doesn't make it so. Nobody wants to feel like a shitty person, but when you're about to steal property from a public school, you're literally depriving people of an education.

>>1817888

>How do I recoup money by using roads, when I pay arbitrary car tax, or when I pay arbitrary property tax and arbitrary VAT and whatever.
Do you think massive modern road works are funded solely by a car tax? In almost every country, a car tax exists to shift some of the burden of maintaining the roads to the people who use them, but a good portion of the bill is still paid for out of the general fund.
It blows my mind that you can bitch about having to pay road tax, and then immediately complain that the roads are "shitty". That road tax is what makes the roads less shit.

You get your money's worth by living in a society that provides you with tons of modern services. Police, fire, healthcare, civil engineering, social welfare, education, military, diplomacy, regulations, etc all benefit you in one way or another. Anyone who thinks all of that should be privatized is either ignorant or sheltered by youth/wealth.

[Anonymous No.1818058]

>>1817664
Just keep unplugging and re plugging the charger and batteries. Try unplugging the charger, attaching the battery, and then plugging it in. If you keep messing with it like that, it will eventually work.
I have the same batteries and charger. The charger is really picky about the battery voltage, so try not to run your batteries all the way down. It's also good for their long-term health if you only use up ~50% of their capacity before recharging.

[Anonymous No.1818059]

>>1817707
My old uni used to sell their used electronics of all types cheap. Then they'd cut the prices in half every week until the items were free.

[Anonymous No.1818071]

>>1816878
https://lightburnsoftware.com/products/lightburn-camera-4k-w

[Anonymous No.1818086]

>>1818055
Idk, I think the main thing taxes are used for is to make politicians' pocket full and allow one nigger to fly alone in giant ass plane for some questionable importance meetings.

[Anonymous No.1818088]

>>1817738
>Human right and a need of a free society

https://youtu.be/3jX5-PFBDtg

[Anonymous No.1818096]

>>1818055

[Anonymous No.1818171]

>>1817971
>failed Flyback transformer
Sounds about right.

>>1818096
nice

[Anonymous No.1818183]

>>1817920
the US

[Anonymous No.1818185]

>>1818183
I though only ex-commie shithole peope steal stuff from work and unis. I guess I will assimilate fast in US, lol. Especially around blacks.

[Anonymous No.1818186]

>>1817942
if you really wnat it to be it's own hardware, just get a cheap micro with usb (atmega32 or something) and make a PCB. program with TMK or QMK and set the macro as ctrl c ctrl v

[Anonymous No.1818233]

>>1818186
TMK? QMK? I would like it to be it's own thing but I'm having trouble picking the right mirco because I lack experience. Ideally I'd like it to be bluetooth.

[Anonymous No.1818245]

>>1818171
any advice?

[Anonymous No.1818249]

>>1818233
Qmk and tmk are custom USB keyboard firmwares you can implement on some micros.

Bluetooth makes it a lot harder, maybe? Ive worked with Bluetooth before but only for audio. I am not sure how you would send serial data over. Someone online has definitely written a guide on this, almost definitely.

[Anonymous No.1818251]

>>1818233
>>1818249
Although a Bluetooth implementation of a copy and paste button does seem to be a waste of effort (why not go the full 9 yardsand make a keyboard at that point), plus you'd need a battery charger circuit as well.

[Anonymous No.1818261]

>>1818245
Replace it? Sounds like failed insulation of the secondary coil, which I wouldn't try to rewind, but if the short is on the outer-layer it's conceivable that you can patch it up with some epoxy or vinyl tape or whatever. There's two main possibilities here:
>inner winding insulation damaged by vibration against metal corner of core, which it's now arcing to
>outer winding or other HV wire insulation damaged by something else nearby, which it's now arcing to
If it's the former, which I suspect is a more likely method of insulation damage, it will be near impossible to fix. But if the inner windings are on the LV side of things (assuming the flyback windings share a voltage reference in the first place) then there's no reason for these windings to arc like you noticed, which gives you some hope. If it's the very end of the windings that's got the issue, you can just snip that bit out without rewinding anything at all.

Now either way it could be difficult to find the source of the problem. If looking for shitstains proves inconclusive, you may need some sort of HV generator (like a tesla coil, maybe a nice easy slayer exciter circuit) to let an arc feel the path to the broken insulation. After removing the transformer from the circuit, of course.

[Anonymous No.1818334]

>>1818086
Here's the budget, decide for yourself.

[Anonymous No.1818344]

I crashed my rc plane pretty bad but I think all the electronics are fine accept the ESC condensator. It came off and Idk on what points it was on. Can anyone help me?

[Anonymous No.1818348]

>>1818344
clean that shit and look for holes
i'm guessing heres one but it might be the all the dust

[Anonymous No.1818380]

>>1818251
I play a lot of VR games and it's incredibly hard to log into a game or paste a link in a virtual video player. Only the virtual desktop has a virtual keyboard usually and it cannot be accessed while in a game. I have to physically take everything off and use my keyboard. With this I can copy paste say my password into the correct field from my password manager.

[Anonymous No.1818415]

>the deeper I get into my EE degree the more I realize I enjoy the theoretical/mathematical aspects significantly than the applied/tangible aspects of the major
oh no no no no no no

[Anonymous No.1818417]

>the deeper I get into my EE degree the more I realize I enjoy the theoretical/mathematical aspects significantly more than the applied/tangible aspects of the major
oh no no no no no no

[Anonymous No.1818440]

>>1818334
I can draw anything I want too

[Anonymous No.1818441]

>>1818417
How?

[Anonymous No.1818452]

>>1818334
>americans spend so much on the military and healthcare that the only other spending categories are literally "not the military" and "other"

[Anonymous No.1818480]

>>1818344
see what pads are on the other side
Doesn't look like there are holes with big enough diameter so maybe soldered onto some smd pads

[Anonymous No.1818555]

>>1818261
Flyback is the black item on the right then?

What are those cans that look like shriveled caps?
They have an Lxxx designation on the board

[Anonymous No.1818573]

>>1817942
Find a cheap bluetooth keyboard. Figure out what lines need to be shorted for CTRL, V, and C.
Extract the PCB from inside the keyboard, and cut away as much as you can... you can probably see where I am going with this. Most of the PCB should be just the contacts for the keys to press, so all of that can be removed.
Build an enclosure for the remaining chunk, which will be the actual logic of the keyboard and bluetooth interface. Attach the two CTRL pins to a toggle switch, and then the C and V to momentary press buttons.

I imagine the final product would be about the size of a deck of cards, and have a "copy" and "paste" button.

[Anonymous No.1818585]

what the fuck is up with this? i don't mind supporting smaller businesses, or american businesses, and don't mind waiting the extra time or whatever but how is this competitive at all? who would pay this?

[Anonymous No.1818596]

>>1818585
Chinks are doing this in the loss.
Nothing beats laser printer and FeCl3

[Anonymous No.1818616]

>>1818596
> Chinks are doing this in the loss.
> Nothing beats laser printer and FeCl3
OSHPark doesn't do their own fab, they are just a middleman between you and the chinaman.

[Anonymous No.1818622]

>>1818616
Then they are doing classic jew

[Anonymous No.1818625]

>>1818596
b-buh how do i get nice soldermask

>>1818616
really? their whole branding is sort of being out of NJ and "American Company™". That sucks they just fab in chinal like the rest when I can just go straight to the fab myself.

[Anonymous No.1818629]

>>1818555
those shriveled caps are shrinkwrapped inductors (hence Lxxx designators)

>>1818585
OSHPark pcb specs are outside of regular diy requirements so you pay extra for shit you don't need (high tg, high tolerances, gay soldermask, enig)
As for their claims to be manufacture in american fab - possible, around identical prices would be with some fabs that make small batch runs so with oshpark quanitity they probably get nice discout and pocket the rest

[Anonymous No.1818631]

>>1818629
thanks friend. best i could find is a replacement flayback for about $80 delivered. Computer still works intermittantly so ill have to decide if I want to replace it or not, could maybe get $100 for it tops anyways so its pushing it
https://www.electronic-spare-parts.com/descript/h/hr_46177.htm

[Anonymous No.1818637]

>>1818629
that's so dumb they market to tinkerer/hobbyist but have features few hobbyists want. thanks for the insight.

[Anonymous No.1818639]

>>1817544
I feel like an optocoupler would work for that.

[Anonymous No.1818643]

>>1818555
The flyback is the big black item in the foreground with the red wire sticking out the top. I assumed it was just a standard EI-core open transformer, but if it's potted in resin or immersed in oil or something you're not going to have a good time taking it apart.

[Anonymous No.1818666]

Is there a better option for an analog scope on ebay right now than this?
https://www.ebay.com/i/282859523947?rt=nc&_trkparms=aid%3D1110001%26algo%3DSPLICE.SIM%26ao%3D1%26asc%3D20161006002618%26meid%3D8ad1805b69724b34af71d31732c6562d%26pid%3D100694%26rk%3D3%26rkt%3D28%26mehot%3Dnone%26sd%3D184020456353%26itm%3D282859523947%26pmt%3D0%26noa%3D1%26pg%3D2386202

[Anonymous No.1818668]

>>1818666
what the fuck is that shipping cost and why do they do this

[Anonymous No.1818673]

>>1818668
"muh heavy"

[Anonymous No.1818690]

>>1818666
for me it's only $20 shipping so that seemspretty reasonable. I'd probably go to an electronics/university surplus or craiglist though, because any money you're not spending on shipping can be spent towards better features if you're committed to budget.

[Anonymous No.1818695]

>>1818690
Craigslist is bare locally, how would I see about universities though?

[Anonymous No.1818707]

>>1818695
just look up university surplus on maps or google and see if anything turns up. not every school has one and sometimes they're not public but many do have large public ones. stuff there (in my experience) usually has pretty light use and is pretty cheap.

[Anonymous No.1818760]

>>1816800
Hello, /out/ here in need of your help!
I'm planing on running couple of these cheap Chinese 5V/1A water pumps:
> https://www.aliexpress.com/item/4001031563938.html
from this charger:
> https://lygte-info.dk/review/USBpower%20Xedain%203%20usb%20QC3%20charger%20XHF30W%20UK.html
You can see the internals if you scroll down a bit.
My question is how likely is that the charger contains some short circuit protection on the 5V outputs?
I cant shake the feeling that the little pumps will have leaks and short circuit the 5V outputs burning down the charger, curtains nearby and the whole flat.
I paid like $8 for it couple years ago if that's any indication of "quality".

[Anonymous No.1818764]

>>1818760
they probably have some ssort of protection diode, if they don't, you could add one.

you could also plug in the USB connectors and then pot the whole thing in silicone or some other plastic/rubber to leakproof the whole thing.

[Anonymous No.1818775]

>>1818585
oshpark charges by sqin instead of per board. it's cheaper after shipping for anything under 2in^2 and also faster, so it's great for smaller boards. also other anons are wrong. they are middlemen but the fabs are in usa, though they're not high quality like you'd expect from a more upmarket place like sunstone.

[Anonymous No.1818778]

>>1818764
Figuring whats what inside is way above my head so adding diodes is out of the question, best i can do is make a "short circuit protector " out of a relay like on youtube. And yes i will be adding some hot glue on the wiring but im more concerned about it leaking through the motor shaft.

[Anonymous No.1818824]

>>1818760
short circuit protection might not save you. those chargers are likely to not suffer water ingress from just being lightly splashed or dripped on due to the internal geometry (unless water builds up in the bottom of the case). but if they get any serious water ingress from a continuous leak or submersion there's no reason why the water wouldn't skip over the isolation barrier and short out the mains itself. you should really place the chargers somewhere that this won't be a risk.

[Anonymous No.1818825]

>>1818666
aaaaaaaaand it's gone.

[Anonymous No.1818834]

>>1818778
oh inside the pump? those things are usually pretty well sealed, that's their purpose. they typically spray everything in there with a conformal coating to prevent that, especially in pumps. i wouldn't worry too much about that.

[Anonymous No.1818835]

>>1818825
it wasn't that good, not too much of a loss. you'll get one, no worry anon

[Anonymous No.1818842]

>>1818666
Holy shit I never seen such a low price on a functioning scope. Sucks to be an europoor.

[Anonymous No.1818897]

This is my problem /ohm/: how to fit a big mess of wires into a small box?

So I grabbed one of these remote switches that uses 12V DC input to run and can switch up to 220V AC. I need it to switch 12V DC loads (LED lights). You can see what the wiring diagram looks like... it's a fucking rat's nest of wires. You basically have to feed +'ve wire to the common point of every relay and then there's an output wire (for NO configuration). And they all share the same ground wire.
And it all has to fit in this small white box. But how?

I can't use ferrules because they stick out too much and I obviously can't use those dupont wires because there's no space. For the output wires, I'd like to have a bunch of cables (4) coming out of it and each one has a DC barrel jack so you can easily plug a DC light into it. Alternative would be to have a bunch of single wires coming out of it and then I could use few of those Wago connectors to connect barrel jacks to them. That sounds messy.

So how would you go about cramming all those wires into that small case? What kind of a "wire loom" should I build for it? I'm hoping I'm not the first one who faced this problem...

[Anonymous No.1818916]

I'm working on a VERY high power buck converter design right now. I found this site https://www.coilws com/ as was wondering if anyone here had ever used them

[Anonymous No.1818930]

>>1818897
I'd have the 4 barrel sockets mounted on the case, and run a common ground wire made of something like rigid 1mm copper wire to all the jacks, possibly making a blobby solder mess. Then I'd clamp a bunch of normal insulated hookup wire in those Vcc screw terminals, and either solder them to a bus-bar, or clamp them in another screw terminal with all its pins soldered together with the help of another piece of solid copper wire. If you end up having a bus-bar for both Vcc and GND that will make providing power to the whole circuit pretty easy, and will avoid having to plug multiple wires into the same screw terminal.

Also see: point-to-point wiring, specifically those little commoning solder terminals.

[Anonymous No.1818939]

>>1818930
Thanks for tips, anon! Much appreciated. I'm still looking at the case and thinking about where to cram everything. I'm thinking about desoldering all those screw terminals. Might be an idea. I have to find some space in there to add all the buswires to connect all the points.
There's no way to mount barrel sockets onto the case. I have maybe 3 mm (1/8") of space before it would hit the relay or a terminal.

[Anonymous No.1818940]

>>1818939
Why are you using such a small box?

[Anonymous No.1818942]

>>1818940
>Why are you using such a small box?
It came with it. Don't have another one and don't want to wait 2+ months for a bigger one from chinkland.

[Anonymous No.1818943]

>>1818942
Damn, that's a pain. Yeah I'd say desoldering those screw terminals is a good idea, but you'll want to ensure your wires aren't going to snap off after soldering them directly to the PCB.

[Anonymous No.1818952]

>>1818897
Those relays are really good for switching high voltage or high current loads. if you're just switching 12V, a smaller, easier thing to implement might be just to jig some transistors up with an RF receiver (like half of what you got already)

[Anonymous No.1818985]

How easy is it to plug a "1-wire" temp sensor into an arduino and get a value? This one is a DS18B20. Never used this standard before.

[Anonymous No.1819023]

>>1818824
The charger will not be anywhere near the water, the pump will. Theres no chance of charger getting splashed. Im worried about the pumps internals flooding and thus via the connected wire shorting the charger output.

[Anonymous No.1819036]

>>1818897

this is just straight-forward monk work. remove screw terminals and solder wires instead. bend wires neatly and lay them down like logs. use superglue to keep them in place. put all the jumpers on the solder side. everything short and neat.
for the LEDs, use thinner wire, put the resistor on the PCB, and shorten the freakin' heat shrink by about an inch. daisy chain the common wires for the LEDs; dont run 4 separate grounds.

[Anonymous No.1819037]

>tfw I finally mastered making double sided PCBs from scratch but I can't come up with any fun circuits to do a real test run.

Any ideas guys? I'd make a guitar pedal but I'm waiting on pots and have only some B500k available.

[Anonymous No.1819039]

>>1819037
Make a solid state tesla coil

[Anonymous No.1819041]

>>1819037
How do you make vias?

[Anonymous No.1819042]

>>1818639
Very interesting idea thank you

[Anonymous No.1819048]

>>1819039
Very very cool but I would need to make myself an actual coil, I have some thin magnet wire, how long would it take me to wind one?


>>1819041
Just like any other hole with a pad around it, because I can't use plated trough holes to connect the two copper layers I just use a piece of wire or solder. Half the time the bottom copper is used only as ground plane so there's no need to worry.

[Anonymous No.1819049]

>>1819041
>>1819048
You can also use small copper rivets.

[Anonymous No.1819050]

>>1819037
>I can't come up with any fun circuits to do a real test run
How? My mind is full of ideas that I can't make because of my lack of an etching setup.
I recommend that you make some sort of audio circuit/guitar pedal/etc. thing to plug into your microphone, doesn't have to have pots. That is, assuming you don't already have a mic preamp, which will make a standard 3.5mm phantom powered electret mic sound a lot clearer. I saw w2aew made a video about an AGC circuit (something often included with mic preamps) that uses series diodes as a variable impedance, real neat looking. Though personally I'd have used an op-amp in there as well to make the feedback loop a little tighter, possibly allowing for adjustable gain, and adjustable rise and fall times.

>>1819041
Vias can be done relatively easily by slightly countersinking the holes, inserting solid-core copper wire, and riveting them with a hammer or punch. With properly sized wire you can get it nice and flush on top and well-enough connected that you won't even need solder.
Plated through-holes are where it gets difficult, but I bought some dedicated THT rivets that work ok.

>>1819048
>Half the time the bottom copper is used only as ground plane
With SMT parts, I'm guessing? Use enough SMTs and the whole plated THTs becomes much less of an issue. I still want to venture down the chemical electroless plating methods though, got my eye on silver nitrate.

[Anonymous No.1819096]

>>1819050
Yeah some guitar stuff would be good, there are things that I should get around to doing but I'm really torn on waiting for parts vs cobbling something together, I've been focusing on audio for a few months and I kinda wanted a pause. Mind sharing any idea for a guitar circuit that doesn't require pots?
For reference I don't play live (I'm not very good) and I don't use a mic. I wanted to make a real fuzzy fuzz for doom metal, but I don't think my B500k will help me much there.

Regarding rivets and vias, I use that solution because it's the easiest and simplest, I only do trough hole so I still have to solder everything else so I don't mind doing the vias too.

And btw since you mentioned your lack of etching equipment, the whole etching setup is real simple, I do heatless toner transfer, it took two days of trial and error but I found a reliable method (4 parts acetone and 1 water, using any paper, the glossier the better) and I can now go from layout to board in 30 minutes.

[Anonymous No.1819240]

>>1818059
so, they took infinite time?

[Anonymous No.1819243]

some people are just born with better reflexes so you will never be as good as aiming at them, they have basically an unfair advantage
so why is using an aimbot to level the playing field considered wrong?
that way the matches will be decided by pure game knowledge, the fairest way of all
tell me i'm wrong, i fucking dare you peasants

[Anonymous No.1819320]

>>1818985
Very easy.

There is a library for that

[Anonymous No.1819327]

>>1819096
Harmonic percolators are pretty straight forward designs and have a real crunch to them. It uses two pots but you can just replace them with resisters (maybe temporarily, and later add on the pots).

[Anonymous No.1819476]

What can I do to harden a computer power supply against a modified square wave inverter?

[Anonymous No.1819478]

>>1819240

You really need to know your limits Anon...

[Anonymous No.1819488]

>lost the auction for a fucking clean analog scope
SIXTY NIGGERS.

[Anonymous No.1819522]

Noticed that in Practical Electronics for Inventors they write R ≡ U/I and σ ≡ 1/ρ instead of =, but P =UI. Never seen this usage before outside of congruence in maths. I'm guessing that is has something to do with for example resistance not being dependent on current but the other way around so to speak, since a resistor has a certain manufactured value. Maybe some can shed some light on this.

[Anonymous No.1819528]

>>1819522
not dependent on current and voltage i mean

[Anonymous No.1819535]

>>1819522
In my EE degree that was usually for "defined as" which is a stronger relation than "equal to". i.e. two things can be equal without 1 being defined in terms of the other. For physical quantities like Resistance, you can get things which have units in Ohms but are not physically the same as resistance, just operates that way in an equation.

Not sure if that's what congruence is.

[Anonymous No.1819553]

>>1819535
Intradasting. Never seen it in any literature in my native languge. Just so i understand, why is P = UI not written with a double bar?

two numbers are congruent modulo n if they give the same remainder when divided by n. for example 9 ≡ 5 (mod 4) since they both have remainder 1 when devided by four.

[Anonymous No.1819554]

>>1819553
ugh, sorry i mean tripple bar

[Anonymous No.1819561]

>>1819554
No sure, just explaining my experience with that symbol in an engineering context.
Could be that V and/or I are "defined" and P is "derived".
Or maybe that Power isn't always VI (e.g. mechanical power)
or that Power is "defined as" Energy through time, which happens to work out to be V*I with respect to electricity.

[Anonymous No.1819589]

>>1816867
>>1816869
Do chinks steal your designs? Im worried about their inspection service.

[Anonymous No.1819609]

>>1819522
>>1819535
In my experience the triple bar stands either for "identically equal to", often used when a function is a constant respect to all variable, or for a definition of a parameter, so it read "is defined as". This last one, depending on the professor, can also be found written as :=

In your case resistance is defined as the ratio between voltage and current, while power is a much broader concept that can be expressed in many ways.

[Anonymous No.1819613]

>>1819589
they probably do, and they give you coupons if you stick your design up on the public PCB design thing they have there so other people can jack it.

but if you're really making something that you're concerned about people stealing (or for any commercial venture) you probably shouldn't use it. I use it for personal designs that people could steal if they want, they're not particularly useful to anyone but me anyways.

also, without a BOM (if you're not doing assembly) it'd be pretty much impossible to figure out what something does just from the traces unless you put it in the name and on the silk

[Anonymous No.1819626]

>>1819589
>implying your shitty retarduino board is worth stealing

[Anonymous No.1819724]

I got an ancient HP power trafo here, p/n 9100-3302. Enclosed so either oil filled or potted, I've determined the primary is an international type, probably 117/220/240v and the secondary has 5 seperate windings. I've measured resistances, inductances and voltages but I need to know how much current I can draw from each winding. Anyone an HP guru? I think I was told it came out of an old computer or calculator but no luck.

[Anonymous No.1819726]

>>1817739
Based

[Anonymous No.1819781]

I'm trying to understand this colpitts oscillator and I can't wrap my head around something. Every explanation I've read says that C1 and C2 are in series because of the common ground. From my point of view, for C1 and C2 to be in series, the current thru both must be the same and I can't see how this can be, as they are arranged in some pi topology with the inductor. Even the simulation show different currents for C1 and C2.
Can anyone help me understand why C1 and C2 are in series and how does this pi network adds the 180 deg phase shift needed for oscillation?

[Anonymous No.1819783]

>>1819781
I wouldn't define C1 and C2 as "in series" with each other.
However, I would say the network (C1, L1, C2) could be in series with C3.
I feel like there's some context missing. Can you link to an example of something that says they're in series?

[Anonymous No.1819784]

>>1819781
>says that C1 and C2 are in series because of the common ground.
Think of them as in series, then tapped to ground
>arranged in some pi topology
pi = delta. Don't let the importance of ground fool you
>Even the simulation show different currents for C1 and C2.
of course, that node has three components, so the series current rule doesn't hold. A better word than series might be a wye
>how does this pi network adds the 180 deg phase shift
that's the inductor's job

[Anonymous No.1819791]

>>1819783
>Can you link to an example of something that says they're in series?
I don't have links, but the wikipedia entry, learnabout-electronics and electronics-tutorials pages state so. Even youtube explanations agree.

[Anonymous No.1819807]

I've plunged the values of the tank in a frequency response simulation with some resistors modelling (grossly, I didn't calculate the exact values) the input and output impedance of the amplifier. There is a frequency that gives180 deg pase shift, and it roughly coincides with the frequency of the output of the simulated oscillator.

>>1819784
>that's the inductor's job
How so? I can't say I have tried all the possible combinations, but I can't see how an array of 2 capacitors and 1 inductor can give 180 phase shift on its own.

[Anonymous No.1819816]

>>1819807
you're overthinking it dude
Current flows one way. "in" is 180 degrees from "out."
"in" the coil is connected to the collecter, "out" is connected to base. that's it

[Anonymous No.1819826]

>>1819816
>Current flows one way. "in" is 180 degrees from "out."
>"in" the coil is connected to the collecter, "out" is connected to base. that's it

Then why don't we just connect the collector and the base with a resistor or directly?
I feel like patrick star here

[Anonymous No.1819849]

>got an analog oscilloscope for free

[Anonymous No.1819850]

SOMEONE HELP ME
I need to fix my nintendo wii
It only boots up at black screen. Help i have to fix nintendo wii for the village

[Anonymous No.1820094]

>>1819826
resistors don't resonate, dummy. If they did, you could
The backwards resonation, where current pulls away from the base, would have to overpower the base's current draw. And only an LC node can bounce that much current backwards

[Anonymous No.1820118]

>>1819850
eat a hearty meal of bugs and pray to your funkopops. the answer will become clear.

[Anonymous No.1820135]

Hello, babby's first coming through. I'm trying to use nodal analysis and I get the following:

(1) Va / 6 + Vb / 12 + 2 - 2 + 3Ix = 0
(2) Ig = 8 V / 4 ohm = 2 A
(3) Ix + Ig + 3Ix = 0 => Ix = 1/2
(4) Va = Vs + Vb

I don't seem to have enough equations to get Va, Vs, and Vb. Vs is unknown here. What do?

[Anonymous No.1820241]

>>1820135
didn't read fully, but can you get rid of the 3Ix and Ix terms?

[Anonymous No.1820249]

>>1820241
Observe the bottom right node has KCL 3Ix + Ix + 2 = 0 => Ix = 1/2 Amp. So I can get rid of it anywhere it appears. I feel like I'm missing an equation but am I just retarded?

[Anonymous No.1820269]

>>1820135
Solve for the current around the loops. You know the current (Va - 8V) / 6 Ohm and (8V - Vb)/12 Ohm. You need to solve for the current going down the 3rd wire to gnd. Since you have 8V/4 Ohm and you solved for Ix, you should be good.

[Anonymous No.1820274]

>>1820118
Can you stop

[Anonymous No.1820276]

>>1819850
>diagnose my problem for me from literally zero information

[Anonymous No.1820287]

>>1820269
I can solve it with mesh currents but I can't do it with nodal analysis. I can't come up with any more equations.

[Anonymous No.1820347]

>>1820276
Im not asking for diagnoses im asking for the manual and any other resources id nees to do it myself

[Anonymous No.1820364]

>>1820347
Learn to use Google faggot.

[Anonymous No.1820378]

>>1820364
Dont have

[Anonymous No.1820439]

>>1820378
Then ask Jeeves to see what other people did to fix this problem when they encountered it.

[Anonymous No.1820452]

All right /ohm/, I've been reading the Horowitz and I'm stuck at emitter followers: as I understand it's important for a voltage source to have low internal impedance, so when a load gets attached, the voltage the load sees remains close to the open circuit voltage; alternatively a load must be big compared to the internal load of the source for those same reasons. Then the book explains the follower emitter like a device that multiplies impedence: it says
>a low-impedance load looks like a much higher impedance at the base; it is easier to drive.
It then derives
>Zin=(hfe+1)Zload
>Zout=Zsource/(hfe+1)
The explaination in the book is kinda confusing to me, and I'd like to know if I understand it correctly: let's say we have a source with some internal impedence Zsource and a load of impedence Zload; if we were to join them together we would get the voltage divider effect, and so the load would see a reduced voltage; if instead we interpose an emitter follower between the two, from the point of view of the source the equivalent impedance of emitter follower and load is ~100*Zload, while from the point of view of the load the equivalent impedance of source and emitter follower is ~Zsource/100. Did I got it right?

[Anonymous No.1820459]

>>1820452
I forgot: the implication is that the load sees a voltage that is very close to the what the actual voltage of the source is, which is ultimately the desired effect.

Oh, and another thing: I got to the point where it talks about emitter follower biasing. The concept itself is really easy, but what puzzles me is why the equivalent resistance seen by the base of the transistor is calculated as a parallel made by R1 and R2 (pic related): it doesn't look like a parallel connection to me. Am I missing something? The book doesn't spend a single word explaining this.

[Anonymous No.1820521]

>>1816800
I have that same tool pouch

[Anonymous No.1820526]

>>1820459
In AC analysis you treat any DC supplies as shorted so VCC and GND are effectively at the same potential which makes R1 and R2 in parallel.

[Anonymous No.1820538]

>>1819724
>I need to know how much current I can draw from each winding.

so simple even a republican can do this: slowly pull more and more current from it until it gets too hot to hold between your ass-cheeks.

[Anonymous No.1820551]

>>1819476
do you need to? Computer power supplies tolerate modified "sine" wave very well.
All you can (and should) realistically do is put a line filter or power conditioner in line with it.

[Anonymous No.1820560]

>>1820287
Sum the currents at the nodes to zero, it's the same thing. You have to solve voltage and current simultaneously.

[Anonymous No.1820562]

How do I test IGBTs and IPMs?
Also on the PCB there are 2 (relatively large) components marked with "BD01" and "BD02", right next to each other, what might they be?

[Anonymous No.1820566]

>>1820378
>access to 4chins
>no access to literally any search engine
what the fuck

[Anonymous No.1820586]

>>1819476
low pass filter. I think as long as you soften the sharp edges a bit, switches and rectifiers can tolerate them better (so it wouldn't necessarily have to be a pure sine)

[Anonymous No.1820606]

Okay I'm trying to troubleshoot an old clock, but I've run into a problem. The clock will start with 1 second. And then progressively get slower and slower. The Crystal oscillator starts out at 60hz, there is no tick, and after 5 seconds there is a tick. Then after about 10-15 seconds the Cyrtal drops to 15-30hz and then after a few seconds starts to get lower and lower.

I've never done this sort of stuff before so I've been guessing and finding out what I can. Still don't even know if this coil is good or not, It shows resistance, but I had figured I could test it with a continuity test, but that shows nothing.

[Anonymous No.1820629]

>>1820606
post pictures.
How high is the resistance? might be too high to trigger continuity.
But like i have no idea how big the thing is, how it's powered, what devices you're talking about, etc. Please give specifics.

[Anonymous No.1820635]

>>1820629
It's a old car clock 12v. Only has a diode, a 220 ohm resistor, the coil and magnet and and IC. I was told the capacitor should be 100uf and that is what was placed on it. The coil reads about 415 ohms.

[Anonymous No.1820636]

>>1820629
It's a old car clock 12v. Only has a diode, a 220 ohm resistor, the coil and magnet and and IC. I was told the capacitor should be 100uf and that is what was placed on it. The coil reads about 415 ohms.

[Anonymous No.1820661]

>>1820636
reconstruct a circuit diagram. just saying the IC name is probably sufficient to start with

[Anonymous No.1820684]

>>1820636
is the oscillator in the IC?
this is kind of a weird clock, I'm not familiar. if you remove the mechanical linkage so there is no resistance on the main output before gear reduction, does it still slow? if it's a crystal it should want to stay at it's resonant freq but this looks like it might be a flip flop based off of a time constant or something.

[Anonymous No.1820705]

degenerate coombrain here. I want to make a diy shock collar hooked up to bluetooth so that it can be activated by someone over the internet
where the fuck do i even start? i can code and I've worked my way around an arduino plenty of times before, and i have access to a shop full of just about every tool and little bit of stuff i could need, but i have nno idea what I'm doing at all.

[Anonymous No.1820716]

>>1820526
Thank you anon.

[Anonymous No.1820722]

>>1820705
Modify existing shock collar.

[Anonymous No.1820729]

>>1820684
That circuit might well be a radio clock, as the coil could easily be a receiving antenna for one of the radio clock frequencies. The coil being directly across the IC does suggest that it's not being driven, at least not with any reasonable amount of current. I'm assuming there's a motor out of view, maybe with an encoder on it.
The drift I can only assume is a result of the signal not being received properly. Some of the radio clock services are no longer running after all. An easy fix would be to throw a crystal oscillator somewhere and broadcast your own local radio clock signal (I think that swiss guy did a video on something similar). Or just solder wires from a crystal-based oscillator directly to the PCB, probably with an MCU to divide and OOK the signal appropriately. Maybe even go all the way and chuck a GPS receiver on there for $15 or whatever.

But now that I look hard, some of the traces just lead into an empty hole or the edge of the PCB, which I cannot comprehend at all. The only explanation I can think of is that before the board was drilled and cut, there were traces connecting all the copper together such that they could electroplate gold onto them. There's no other use for those small holes in the board that I can think of, at least. If so, it's a primitive but neat technique.

>>1820705
Easiest method would be buying an existing shock collar and jamming an ESP8266 in there. You could also make your own HV boost or flyback converter, but you'd need to do testing to figure out what's a good level of shock, which might not be terribly fun for you. There are existing potted HV "taser" modules that you can purchase and would be relatively easy to integrate into a project, but they're not that small.

[Anonymous No.1820736]

>>1820729
I think that buying an existing shock collar and then modifying it would be the smartest option for sure. I think the smartest and safest option would be only modifying the on/off trigger and nothing else so that I couldn't accidentally max out the power on it or anything unsafe.

Are there lots of guides on how to use an ESP8266 online? I dont really have the confidence to just crack open the manual and wing it.

[Anonymous No.1820759]

>>1820705
does it specifically need to be bluetooth? the picture you posted already has a remote control, if you can just open that up and swap the button with a relay or transistor then you can control it with pretty much any internet enabled iot bullshit you can find on sparkfun or aidsfruit probably using an example they give you.
it's possible with an arduino too but you will probably need it connected to a computer unless arduino make iot devices i don't know.

[Anonymous No.1820820]

>>1820759
no it doesn't need to be bluetooth. I was planning on having it simply setup alongside a discord bot so anything that I can plug into my PC will work perfectly fine.

[Anonymous No.1820847]

Ive tried every kind of search but am coming up empty. Can anyone help me identify this inductor? the first character is kind of rubbed off. I've tried every kind of combination but can't seem to come up with any results. Anyone better at me than this? I would really appreciate it

[Anonymous No.1820859]

>>1820847
better photo to see where on PCB it is?
Might be custom part

[Anonymous No.1820871]

>>1820859
its part of a samsung 14V power supply

[Anonymous No.1821072]

>>1820684
No the oscillator is not in the IC, It's an 78' clock out of a Z car.

[Anonymous No.1821079]

>>1821072
Well after digging, it seems no one actually has a diagram for this IC. Found an old magazine from 2002 that covers it (about the only source I could find) And that it's an in house chip.

[Anonymous No.1821087]

>>1820871

looks like a double common-mode choke. if one of the coils is broken, you can just short it and it wont make any difference. or, if you're keen, you can unwind the coil, count the number of turns, then rewind it with appropriately sized magnet wire. coils are one of the rare components that one can repair. however, this assumes you can remove the core. if you cant, you can still do it, but it's a long slog threading the wire through the holes.

>>1821072
>No the oscillator is not in the IC

well, it kinda is. almost certainly that's a CMOS chip that's forcing the crystal to oscillate and dividing the frequency to drive the coil which is advancing the movement. after 40 years, you'd expect that the chip or the crystal would have become senile. assuming the chip is long obsolete, you'd probably wanna recreate a 60Hz pulse some other way. i remember using a chip that divided a color burst crystal (around 3.58Mhz) down to 60Hz.

[Anonymous No.1821095]

>>1821087
>recreate
I figured as much. Not something I've done before, but also not something I don't see I couldn't do. Was just curious what could cause a crystal to slow it's pace like that. But age being a factor was something I figured.

[Anonymous No.1821099]

>>1820736
Buy a USB ESP8266 dev board on aliexpress and just use the arduino environment to program it. Once you have a working prototype, you can push the same code to a tiny standalone ESP8266 board using an appropriate USB programmer. Not sure what sort of programmer you need though.

>>1821072
Fuck, that's an in-house IC with no documentation whatsoever.
Can you measure the frequency across the crystal and see if that's changing at all?

[Anonymous No.1821104]

>>1821099
Yea that's what I had measured before. The frequency would sit at about 60hz for 10-15 seconds, then it would start to slow down to 15-30, then 10-20 and so on.

[Anonymous No.1821106]

>>1821099
Everyone just uses USB-TTL adapters to program ESPs.

[Anonymous No.1821113]

>>1819488
Dude, just blow one in your uni already.

[Anonymous No.1821115]

>>1821104
Wait, you're telling me that the crystal itself is oscillating at 60Hz? Never thought that was possible.

[Anonymous No.1821116]

>>1821104
can you try to remove the mechanical linkage to see if the current draw of trying to drive the mechanics is what's making the freq sag? that seems unlikely but possible. without a datasheet it will be difficult to do this, but you could always DIY a replacement circuit and interface it with the mechanical parts if you still want the front end to look the same.

[Anonymous No.1821118]

>>1821115
oh wait i didn't even think about how slow that is. i don't even think you can get an oscillator that slow? how bizzare. are you sure you measured correctly, >>1821104 ?

[Anonymous No.1821119]

>>1821115
>>1821118
>>1821116
So make sure I'm doing this right. power up the circuit and place my leads across the crystal and I should get a frequency right? Let me check again while I wait.

[Anonymous No.1821124]

>>1821119
So this time it started at 300hz, dropped to 80, back up to 160 and down to 60 up to 120 and down to 40 and so on until it would not read anymore.

[Anonymous No.1821129]

>>1821124
are you using a multimeter or an oscilloscope to check? could be the speed is too fast for multimeter. That would explain the jumping results

[Anonymous No.1821131]

>>1821129
Using a Klein MM600 in Frequency mode.

[Anonymous No.1821134]

>>1821131
the spec says that goes to 500kHz so it should be fine. That is some really weird behavior

[Anonymous No.1821144]

>>1821124
Desolder the crystal and chuck a scmitt inverter across it and see what happens

[Anonymous No.1821157]

What kind of device can I make to prevent mold and bacteria from fucking in my mini split air conditioner?
>uv-c
First it would degrade plastic, second, good luck getting real UV-C bulb in current day situation.

I think that ozone generator would be a perfect solution, since ozone is basically bleach but gas, should kill everything, including humans. But how do I make one? What do I need for this, besides high voltage?

[Anonymous No.1821179]

>>1821157
> First it would degrade plastic,
coat the plastic to block UV-C, simple as.
> But how do I make one?
any spark-gap.

[Anonymous No.1821233]

>>1821179
>coat the plastic to block UV-C, simple as.
I've doubts. All UV-C gimmicks were made out of sheet metal and quartz glass.
>any spark-gap.
What is the easiest way to get a reliable spark gap? Flyback transformer from TV (with all aux circuitry)?

[Anonymous No.1821246]

>>1821233
>All UV-C gimmicks were made out of sheet metal and quartz glass.
Blocking UV-C isn't hard. You don't need quartz glass.
> What is the easiest way to get a reliable spark gap?
Buy chinesium 10kV transformers and make a transistor based oscillator to feed it. This is the basics of electric lighters.
https://electronics.stackexchange.com/questions/171210/understanding-a-2-transistor-oscillator

Here's an all-in-one ready to go based off a battery:
https://www.ebay.com/itm/15KV-High-Voltage-Inverter-Generator-Spark-Arc-Ignition-Coil-Module-DIY-Kit-3-7V/362627409161?hash=item546e472509:m:mC63AYuWI_4X9vIc3uzmaMQ

You can plug in any DC wall wart if you want, and run a bunch in parallel
Note the spark gap will only be about a cm with that voltage.

[Anonymous No.1821256]

>>1821246
What is the piss simpliest mains switch-mode power supply circuit? I'm 100% sure I can make use of TV flyback in this case, even re-use giant ass NPN it has near the coil.

[Anonymous No.1821363]

>>1821256

walk into thrift store with a $20 bill and walk out with an armful of SMPSs.

[Anonymous No.1821427]

>>1821363
Neat idea, I never considered doing that.
So I'm not the guy who asked the question, but how easy would it be to turn one of these into a HV PSU? Replace the step-down flyback with a step-up flyback sure, but you'd also need feedback too. Well, that anon can probably do without feedback so long as there's a zener diode or MOV or whatever on his input side to protect the switching transistor, since he's got a pretty constant load. But the negative resistance might cause it to arc in fits and starts. Anyhow, for a more precise HV(DC) PSU, I'd either need a feedback winding or some sort of opto-isolated feedback circuit, the latter of which is kinda tough at the 100kV level. I think ideally I'd have a feedback winding that lets me adjust the output voltage, but I'm not terribly sure how to wind such a thing.

[Anonymous No.1821429]

>>1821427
>, but you'd also need feedback too
I don't think cheap'o chargers have a feedback.
In case it is required, you can always wind a winding.

[Anonymous No.1821496]

>>1821429
>I don't think cheap'o chargers have a feedback
They should have some sort of feedback, otherwise what would stop the voltage from rising to fuckoff levels without a load? Some have poor regulation for sure (LV zener + opto maybe?) and they drift up a couple volts when unloaded, but I don't think they're entirely feedbackless. Either way, I suspect the charge controllers have a generic feedback input pin that can take either input directly from an opto, or a slightly processed waveform from a FB winding. Not sure which method is cheaper though, but surely a TL431 would be cheap enough and give a very well regulated output. Or you know, just add an LDO to the output circuitry, not like the poorly regulated PSUs are designed for more than 1A or so.

As for making my own feedback winding, worry not, I've got all sorts of magnet wire lying about. One of which is wrapped about a cardboard box in an attempt to make an AM antenna, which didn't work. A TL431 or reverse diode stack or whatever simply isn't an option once you get a high enough voltage anyhow. I was considered running a few MΩ to a feedback opto, but the resistor I'd need would be more like a few GΩ in order to not load the output significantly, plus be physically long enough with low surface leakage, and those aren't cheap. From what I know, a FB winding's peaks will be directly proportional to the peaks of the output winding, regardless of if the output winding has a big rectifier and filter cap on it.
Though the other problem is that my primary winding will only have a couple of turns on it, so getting the feedback winding to have few enough turns such that it won't kill a comparator might be tough.

[Anonymous No.1821497]

>>1820538
There are several windings, not interested in running the primary into saturation and ruining it as I hate rebuilding transformers and I'm already having a ton of fun

[Anonymous No.1821542]

How can you mount binding posts to a metal case without shorting it to the case?

[Anonymous No.1821545]

you don't

[Anonymous No.1821549]

Found me a 24V/5A adapter, figure it could be the basis of a neat redneck bench psu.

[Anonymous No.1821638]

I got this duct fan that I'm trying to rig up to cool a system and the 12V 10A power supply I got for it JUST can't start it

it kicks on for like 1 sec then during acceleration dies, repeats.

Is there a way to use some AA batteries or something to rig up a way to give it a little extra kick during startup? it's draw is listed only at 3-5amps so once it gets going the power cord should sustain it no problem.


I know very little about electronics sorry

[Anonymous No.1821649]

>>1821638

see >>1809279 in the old thread, and the few followup posts

[Anonymous No.1821654]

>>1821649
thanks but that is honestly way over my head, I understood like 10% of that lol
but I did just think of something and this is probably stupid but.

Since I'm just plugging it directly in it's trying to go 100% off the bat, if I put a dial or something in between and started it at like 25% then dialed it up, would it soften the initial draw and allow it to work at full blast after dialing it up?

[Anonymous No.1821656]

>>1816987
Don't be a pussy, make both leads negative and send it to the fuckin' ground like a man

[Anonymous No.1821684]

>>1821654
>if I put a dial or something in between and started it at like 25% then dialed it up

yeah, you could add like some car lamps or 12V or 120V halogens. that was the point of using a coil in series as per the other thread: it acts like a temporary brake on the current, lowering it down at first, then allowing all (most) of it to go unimpeded. the other suggestion would likely work as well: first charge a big 10,000uF 16V cap, then connect both across the fan. the cap acts as a temporary battery, boosting the overall current capability for a few seconds.

[Anonymous No.1821702]

>>1821684
God I honestly hate electronics they make me feel so god damn retarded lol.

Ok so when you say a coil in series, do you literally mean putting the charge through a spring?

[Anonymous No.1821752]

>>1821702
>>1821684
ok well I thought I was wiring it wrong but turns out I just fried both my potentiometers because they smell like burnt ass now


but am I understanding the concept right? This is what I was referring to when I said stick a knob in there start it low and dial it up.

if I simply started the fan on low, it would have a much lower startup spike and then I could just dial it up to max and let it go right?


granted im now out of potentiometers

[Anonymous No.1821768]

>>1821752
>running couple of amps through potentiometer
honestly, just buy a better brand 5-10A 12V power supply and be done with it

[Anonymous No.1821795]

>>1821768
yah sorry I'm retarded.

Back to my previous statement though because at this point im just trying to understand how this shit even works.


Is it possible to use a 12V battery wired in somehow as a source for the extra needed startup amps when it's being fired up? and then the power supply maintains after?

[Anonymous No.1821837]

>>1821795
>>1821768
Welp I tried it out and it worked perfectly

I had 8 AA batteries in series, plugged in the PSU to start it's little half sputter and then I put the batteries in parallel with the PSU for like half a second and it gave it the amps to start the fan, instantly removed the batteries and the PSU maintained the fan

[Anonymous No.1821842]

>>1821157
>>1821429
nvm, figured it out. I used mouth wash on AC and now it smells nice.
Still gonna play with tv flyback

[Anonymous No.1821951]

>>1821837
a better brand power supply usually is designed with better parameters overall and should be capable of powering motor on startup not just resistive loads

Your battery test just showed that it needs some extra current at startup and either additional capacitance on output or series inductor might help as well without relying on batteries

[Anonymous No.1822088]

I am really confused, is there any reason I shouldn't be able to get continuity on any part of this coil? >>1820636 I figured I'd at least get a tone somewhere, but I get nothing even when I put the contacts right next to each other.

[Anonymous No.1822101]

>>1822088
Coils are made of "magnet wire", which is wire with a thin enamel insulation. This is so that the individual strands of wire don't short each other, which would defeat the purpose of winding a coil in the first place. Often this insulation is brown or colourless so it looks similar to raw copper, other times its red or green which is more obvious. In order to strip insulation off it for soldering, people usually use sandpaper, but a solvent like acetone will work well too, and in a pinch just heat from a lighter should do the job if you wipe the residue off after. I would endeavour to keep the insulation on the coil body intact, because if it starts shorting to itself you'll have ruined an otherwise pretty good coil.

If you're unsure what it's being used for, a look at the wikipedia page for "inductor" or "solenoid" should do the trick.
Is the coil itself hollow? Is there any magnetic part deliberately nearby or inside it? Because I'm still not sure what the coil is there to do.

[Anonymous No.1822103]

>>1822088

if you're using a continuity tester, those are only good for low resistances. a coil like that will have 1000's of ohms of resistance so you need to use an homo-meter.

[Anonymous No.1822106]

>>1822101
I figured that was part of it, which was why I was trying the test leads at each end.

>>1822103
That I didn't think about, I know this one only has a resistance of 767 ohms.

I'm just completely lost at what could be causing these to fail unless it is 100% the IC. I have two of them right now and they both have the same issue, will get 1 tick under power, then a tick every now and again for a few seconds then nothing. This is both with and without them attached to any gears.

[Anonymous No.1822118]

POST CIRCUIT DIAGRAM

[Anonymous No.1822133]

>>1822118
I can't, It's literally impossible as the IC is in house. So I have no idea what it's doing inside that.

[Anonymous No.1822208]

Hi,
I want to make a (battery powered) circuit that monitors a door
If someone closes the door, I want the arduino to turn on, send out a signal over wifi, then turn off
If someone opens the door, I want the arduino to turn on, send out a signal over wifi, then turn off

The input is easy enough with a reed switch and maybe a latch, but I have no idea how to tell the Arduino to turn on and off in response to a flip in input. Could anyone offer any advice?

[Anonymous No.1822219]

>>1822208
You probably want /mcg/, but it should be pretty easy. I know with ESP32 you could use one of the pins to take it out of sleep, send the signal, then go back to sleep.

[Anonymous No.1822223]

>>1822133
Ok I can assume that it's a crystal oscillator with an internal clock divider and solenoid driver. The solenoid is probably there in order to drive the mechanical side of the circuit, be nice if you could confirm this. Might be a similar IC that does have a datasheet, but it isn't critical to know exactly what's going on there. Because your DMM is only good to 500kHz and your crystal is probably a ~4.2MHz (which is more sensible than 60Hz or 4.2GHz, and exactly 2^22Hz, making it easy to divide), it's very likely that the crystal's oscillation frequency just wasn't being measured properly by your DMM.

There are two likely sources of potential error, the crystal itself or its driving circuit, or slip within the mechanical driving mechanism (the solenoid). While you're unable to measure the crystal frequency it won't be easy to tell if the crystal itself is working properly, but measuring the frequency across the coil should tell you all you need to know. There may be conformal coating over the solder pads, so quickly reflow those and/or abrade away any coating if you're not getting a reading on them. Clock dividers don't simply slip, so that won't be the issue.
If the frequency across the coil is constant, then it's the electromechanical coupling that's an issue, fixing which will be a troubleshooting process that I'm not qualified to inform you on. Maybe disassemble, replace the grease, perhaps replace any bushings, that sort of thing.
If the frequency across the coil is what's varying, I'd first replace the 4.1945MHz crystal with an identical new one to see if that solves the problem. If that doesn't solve it, then I can only assume that it's the driving circuit skipping cycles. Fixing this will probably entail wiring a seperate clock driver (schmitt inverter) up to your crystal and feeding the output into the right one of the two crystal pins.
It's also possible that adding some burden capacitors in the realm of 10pF from the crystal to ground will help.

[Anonymous No.1822250]

>>1822219
I'll try asking over there, thanks

[Anonymous No.1822251]

>>1822223
>The solenoid is probably there in order to drive the mechanical side of the circuit, be nice if you could confirm this
Yes it does, simple mechanical magnet spins on polarity shift to turn the gears.

>If the frequency across the coil is constant
On one it is and I figured out the problem was mechanical on that one, the gear had separated from the permanent magnet, the other is not and I'll have to hook it back up.

If I recall though it also had a coil that at 60hz. I'll double check it though.

I appreciate the help, I've been watching videos on the electrical breakdown for these sorts of clocks, but the IC part left me behind.

[Anonymous No.1822262]

>>1822251
Look for american ones that are less likely to use that Hitachi IC, if you want to know how the IC works. But it will just be an inverter with positive feedback, a long chain of clock dividers (22 stages), and some output transistors. All the different pins that are grounded are possibly the other ends of differential outputs for the coil output, different ground references for different sections of the circuit, perhaps hard-programming pins for setting the clock division ratio or output current, that sort of thing. There's a few too many NC pins to think they just had some left over (it's a DIP16 not a DIP14 after all), so maybe those are deliberately unconnected programming pins. Anyhow, in all likelihood the IC itself is fine, so that isn't all that important. Unless the zener has slowly broken down and given the IC a hot supper.

[Anonymous No.1822341]

>>1822223
Good call on the crystal being too fast. I was the one who mentioned checking the spec for the DMM, but I forgot to imagine if the frequency of the crystal wasn't the standard quartz xtal used in watches. Those are like 32kHz.

[Anonymous No.1822401]

>>1822341
32.768kHz to be precise. That's 2^15. For crystals that likely lead to a primitive clock divider (as opposed to a more advanced digital timing IC) it's a good guess that its frequency is also a power of 2. Also crystal oscillators don't go into the GHz range, that's the kind of place that you find SAW (surface accoustic wave) oscillators or MEMS oscillators, which I think are usually in different, smaller packages. Or crystals as part of a PLL frequency multiplier, I guess.

[Anonymous No.1822423]

>>1822401
GHz range stuff is more commonly Gunn diode oscillators (negative resistance oscillator). That'll get you 30+GHz. It's pretty common technology to see in police radar units which operate in the range of 10-40GHz (X-band, K-band, Ka-band). MESFET and HBT based oscillators will get you into the hundred of gigahertz. Unfortunately with anything RF properly designing for operating at those kinds of frequencies is very difficult and expensive.

[Anonymous No.1822432]

>>1822423
I wonder if someone (looking at you, dave) has done a teardown of a police radar

[Anonymous No.1822483]

>>1822401
>>1822423
>>1822432
do you really think this is the oscillator he has in his car clock? I'm hesistant to think they would use a seemingly high spec component like that when quartz xtal at 32khz is the norm for clocks

[Anonymous No.1822537]

>>1822483
See for yourself: >>1821072
It says 4194.5 on the side of it, which is basically exactly equal to 2^22 if that's in kHz. 32.768kHz crystals are actually oddballs and more delicate than normal MHz crystals because they need to be made in a tuning-fork shape. While it's possible that it's a lower frequency crystal, I very much doubt it.

And don't misunderstand, I'm saying that it has a standard cheap ~4.2MHz crystal, and a ~4.2GHz crystal would be comparatively far more exotic. I thought he said somewhere that it was a ~4.2GHz crystal, but I can't find that anywhere in the thread, so maybe it was my misreading of something.

[Anonymous No.1822565]

This might be a stupid question, but here goes:
If I have two appliances plugged into mains is it safe to assume they use the same earth reference?

So I have a 12V power supply feeding a step down converter to 5V that powers a microcontroller. If I plug the microcontroller into USB while the power supply is on (I won't, just wondering), would the ground of the step down converter and the USB plug be the same?

[Anonymous No.1822601]

maybe anyone has code for digital calipers protocol implemented in stm32 HAL? I have a hard time figuring it out and arduino code provided is very nonintuitive

[Anonymous No.1822674]

I have a KR-10SP K-band radar unit. Got it second hand. The analog boards are complex but the oscillator itself is the Gunn diode+cavity resonator bolted to a conical antenna. It's received back through the same antenna and pops out of the waveguide at a lower frequency somehow. The waveguide connects to the first analog board through an RCA connector and the board is definitely not designed to handle millimeter wave signals so the returned signals has already been mixed with the local oscillator and the LO is completely removed. I'm not sure how, there don't appear to be any electronics.

[Anonymous No.1822678]

>>1822674
K-band radar unit.

[Anonymous No.1822680]

>>1822674
>>1822678
Gunn diode oscillator and antenna

[Anonymous No.1822681]

How do I check current consumption of a device plugged into mains with a multimeter?
I tried just sticking the probes in but it went bam and melted the tip of one of the probes.

[Anonymous No.1822687]

>>1822674
>>1822678
>>1822680
First analog board, probably for amplification and signal conditioning

[Anonymous No.1822688]

>>1822674
>>1822678
>>1822680
>>1822687
Crude reverse engineering of the outlined half of the front end. Mostly correct but not guaranteed to be 100% right.

[Anonymous No.1822691]

>>1822674
>>1822678
>>1822680
>>1822687
>>1822688
There are two digital boards. I never took pictures of both. Fun story, I don't have a license to operate this radar gun and the few occasions I drove and used it I was doing so illegally. Twice I was pulled over by the NYSP and questioned. One cop didn't really give a fuck about the radar and cared more about me having a light out. The other one gave a lot of fucks and was probably looking for a reason to arrest me but ultimately couldn't find any laws I was breaking so he let me go. Fun times.

[Anonymous No.1822853]

Hey /ohm/. Thanks for your help with my project. I had some questions and got some great input here that probably would have taken a long time to figure out on my own. It's not 100% yet as I need buckles and then to mount the board to the strap, but electrically it's all done.

[Anonymous No.1822939]

I'm hitting 120°C with the probe directly on the led. Is this too hot?
INB4 GTFO with that janky shit.

[Anonymous No.1823006]

TS-80 or KSGER T12?

[Anonymous No.1823034]

>>1822853
Good job OP.

>>1822939
Too hot is relative to the operating parameters of the LED. Do you have documentation for it? JT-40 didn't yield anything beyond my desire to keep searching, oh which i did very little.

[Anonymous No.1823059]

>>1823006
depends, do you want a portable iron?

[Anonymous No.1823065]

>>1822691
Yeah its always a fun scenario when the cop wants to arrest you but has no probable cause. Before the age of dash cams they would have just planted weed on you.

[Anonymous No.1823068]

>>1822681
It has to be inline (basically) and yeah it's easy to blow the fuse. Fortunately their replaceable.

[Anonymous No.1823076]

>>1822681
you have to run the current through the multimeter ie have half the plug in the outlet and the other plug connected to one of DMM terminals, and then plug the other DMM lead into the other part of the outlet.

[Anonymous No.1823079]

>>1822565
if the plugs are grounded they should be

no guarantees if it's just a two prong plug

[Anonymous No.1823082]

>>1822853
awesome!

[Anonymous No.1823102]

>>1823059
Currently I have no need for portability. I'm more concerned about the performance: I tried cheap irons before and I had them either so hot that there was a ton of oxidation, or couldn't provide enough power to keep the solder melted on the pads.

[Anonymous No.1823131]

>>1816800
What is the closest equivalent to a 15uf capacitor commonly available nowadays? I'm working on an amp from the 60s (solid state) and want to replace one that is suppose to be that value but is now far out of spec. I have a few 9uf caps that I could parallel, but I'd prefer to be neat.

[Anonymous No.1823143]

Just linking to a project I'm working on, posted on /mcg/
>>1823141

A force feedback steering wheel setup containing power electronics, microcontrollers, USB and Bluetooth.

[Anonymous No.1823145]

>>1823102
>too hot
>couldn't provide enough power
That's the characteristic of a standard PTC soldering iron, i.e. an iron with very poor passive temperature regulation. Both the T12 and TS80 have proper temperature control circuits.
Performance wise, a T12 out of the box should outperform a TS80. While a TS80 is able to be programmed with relative ease, I've never needed to do such a thing to my T12, so I'd recommend the T12. It's cheaper too, both for the iron/station itself, and for any replacement tips.

[Anonymous No.1823151]

Whats the most practical method for repairing PCB traces going from pad to pad? Get some solder pins and bus wire? If I go with solder pins what are some ways to fasten them down securely? Or are there some other options?

[Anonymous No.1823158]

>>1823151
I always use enamel wire and coat it with some special loctite coating to mechanically fasten it. Hot glue should work the same.

[Anonymous No.1823191]

>>1823145
Good, thank you anon.

[Anonymous No.1823216]

>>1823145
Oh, since you own it, do you by any chance know if you can plug in a hot air blower and use it that way? I saw that there's a similar product that instead of an iron has a blower and on the front says "SMD rework station", but the connector seems identical.

[Anonymous No.1823276]

>>1823216
I've seen those on ali occasionally, but I doubt they're completely swappable. The pinout on the T12's cable specifically caters to the T12 tip and its element+thermocouple arrangement (along with an extra thermistor and tilt switch), which I doubt the hot air blower follows. The hot air blower needs both power lines for the fan and heater, and I doubt the thermocouple is put in series with the element in this case. It also probably won't need a tilt switch.

Instead I'd just buy one of those AC-DC power-brick-style hot-air controllers, the ones with a little 7-segment display and a couple of buttons on them.

[Anonymous No.1823387]

>>1823131
Never mind. I had some 10uf and 4.7uf capacitors that I ended up putting in parallel to get the value I wanted.

[Anonymous No.1823410]

>>1823387
Pretty sure 15 is one of THE common values:
>10
>(12)
>15
>(18)
>22
>(27)
>33
>(39)
>47
>(56)
>68
>(82)
>100
Where the () denotes the 2^(1/12) values, and the not () denotes just the 2^(1/6) values, which are the most common. Notable exceptions being the somewhat unusually common "20" and "50" that you'll see with some components.

[Anonymous No.1823516]

rollan

[Anonymous No.1823553]

does hot airing smd ICs on etched pcbs without solder mask work? or do you need solder mask in order for the solder to not create blobs and short all the legs together?

[Anonymous No.1823619]

>>1823553

solder mask is the cherry on the sundae. 90% of your success is gonna be due to adequate flux usage.

[Anonymous No.1823862]

I have a VFD that was given to me
Is there a way to test if its dead, I do NOT have a 3ph motor right now but I will probably be buying one in the near future. I want to test it to make sure its not bad, and I dont want to kill my motor by putting a bad one on.

[Anonymous No.1823898]

Any way to figure out what the voltage is supposed to be for this RC controller? Bought I shit ton of RC stuff in bulk for pennies on the dollar.

This particular controller won't turn on even with 6 new AA batteries. I'm measuring 7.5 volts from the red wire to the black wire, so there is continuity. Im basically an electronics noob does anyone have any advice on how to troubleshoot this? I looked at the other side of the board and especially the solder joints for the on/off switch, they are solid.

[Anonymous No.1823899]

>>1823898
Fuck forgot pic

[Anonymous No.1823911]

Apparently my motherboard only has one system fan header, so I can only use one of my two case fans.
The recommendation online is to purchase a "cable splitter".
Isn't this just each pole split into two wires leading to each fan? I could easily do it myself then

enjoy this abstract painting

[Anonymous No.1823931]

>>1823898
it should run on 6-9V, since individual AAs run from 1.5V down to 1V over their lifespans.

measure the AAs out of circuit. if they're brand new they should read 1.5V individually for 9V total. if that's true then the voltage sagging to 7.5V suggests that your RC controller is drawing a surprising amount of current, which might indicate what sort of fault you've got.

[Anonymous No.1823948]

>>1823931
Tested each individual battery and they all measure low 1.5 and high 1.4 so that's normal. Not sure what to do from here, I'll try to trace the voltage to see where to sag is.

[Anonymous No.1823963]

>>1823931
>>1823948
another update, I put different batteries and and now I'm reading 8.9 to 9 volts., but it still will not turn on...

[Anonymous No.1823972]

>>1823911
Yup. You might run into problems if there isn't sufficient power for both fans at once but generally doubling should fall within decent design.

[Anonymous No.1823976]

>>1823931
I assume it wanted 6 AAA batteries? post pic, make, model number, etc. How can we help if you don't give any information about the controller.

[Anonymous No.1823986]

>>1823972
Cheers. I'll just up the voltage in BIOS then.

[Anonymous No.1823989]

Whats the difference between these two?
https://www.ebay.com/itm/AC-250V-20A-50-60Hz-Power-EMI-Filter-HA32L-20A-for-Date-Cable-USB-hub-HDD-CD-ROM/264290017115

https://www.ebay.com/itm/Single-Phase-AC-Power-Line-EMI-Filter-AC-115-250V-50-60Hz-20A-Suppressor/123684313976

[Anonymous No.1823996]

>>1823976
Refer to the other post I made, it reads 9 volts after changing out batteries again, also I did include a picture. There's no model number on the controller. I know its from an "s107g 3.5 channel gyro system". Can't find specs or schematics of controller online.

[Anonymous No.1824006]

>>1823898
>>1823931
>>1823976
Okay, something very peculiar now. The switch I circled is the on/off, it is currently in the off, with the circuit reading 7.5 volts when it is off. When I switch it to ON and continue to read, the voltage drops from an amount down to zero over time.

For example, when I flipped the switch immediately after putting the batteries in, the voltage dropped to like 1.5 and dropped steadily. I left for a few minutes, came back, did the same thing, this time the ON LED lit up dimmly and the voltage started to drop from 3.5. Its behaving like a capacitor when I turn the switch to ON.

[Anonymous No.1824013]

>>1824006

either your batteries are very dead or the thing is drawing a huge current. to test batteries, you always do it under load. e..g. put 100ohms across it while measuring. carbon batteries are famous for showing full voltage even when they're completely exhausted.
or, if somehting is drawing a lot of current, feel around if anything is hot. esp that chip.

>>1823989

second one has more stuff, more caps, twice as many coils. and component values are actually specified, which signals more professionalism.

>>1823862

if you can scope high-voltage sources, then replace the 3 coils with any suitable load, like 3 lite bulbs, or heating elements (toasters), etc.

[Anonymous No.1824016]

>>1824013
>second one has more stuff, more caps, twice as many coils. and component values are actually specified, which signals more professionalism.
My project says to use the first one, but I can only buy it from china, or from Amazon and it says itll show up in mid july

Will the second one work fine as a replacement then?

[Anonymous No.1824017]

>>1824006
I'm fucking retarded and forgot pic again I guess it doesn't really matter. Here's what I have now.

What I circled are capacitors and when I take a reading I see they are slowly charging up, currently 3 volts. The rectangle is the ON/OFF switch, and I drew a line to the ON contact. It reads exactly the same as the capacitors do. The OFF contact reads at 8 volts now, and "charges" up to 9 >>volts and stops there once the capacitors are full.

Going to check for current now instead of voltage.

[Anonymous No.1824020]

>>1824016

whichever one you choose will work the same. and if you use none at all, it'll also work the same 99 times out of 100. these things are only used to pass UL and EC type certifications. they have very little real world utility.

[Anonymous No.1824031]

>>1824017
Okay final update. It randomly started working and I decided to fly the helicopter. 3 seconds into the air, all four of the blades literally snapped off and flew in all directions. Its broken now :(

There are four extra blades but I don't want to try my luck.

[Anonymous No.1824034]

>>1824031
>all four of the blades literally snapped off and flew in all directions.
based chinkshit

[Anonymous No.1824035]

>>1824031

probably what was taking a lot of current was the LiPo batteries in the heli charging up. once they were full, there was enough juice to power the controller.

and, yeah, toy helis are crazy hard to fly unless it uses a lot of AI to help you out. cheap helis dont have AI.

[Anonymous No.1824138]

How are you supposed to draw a diode bridge without drawing a swastika? I was nearly excluded from uni for this

[Anonymous No.1824146]

>>1824138
>I was nearly excluded from uni for this
Kek, I sincerly hope you are fucking joking. That kind of thing could easily be missed.

[Anonymous No.1824193]

I am having trouble powering a remote using a Raspberry Pi. There is the proper Voltage of 1.6v between Point A and B but the remote just doesn't work.
Can anyone tell me where the design error is? I am a complete noob at circuitry so its probably just something stupid.

[Anonymous No.1824204]

>>1824193
You need a buffer, the ic cannot source enough current. Consider an emitter follower.

[Anonymous No.1824207]

>>1823899
Tell me the IC number and maybe trace circuit too, I'm interested in what parts cheap RC shit uses.

>>1824017
Oh is that an IR controller, not a radio controller? Still somewhat interesting.

>>1824193
DOn't use a FUCkiNG VoLTLAGE DIVeiDER as a Powere SUpplY
use a linear regulator (like an LM317) or emitter follower (if you don't have a single NPN transistor I'm going to shoot you) instead, probably with a filtration cap or two
the voltage at the output of a voltage divider is heavily dependant on how much current the load uses, because all that current used by the load goes through the upper resistor (220Ω in this case) which increases the voltage drop across it via V=IR. You also necessarily have to waste a lot more current through the divider than goes through the load in order to get passable ripple-rejection.

[Anonymous No.1824215]

[Anonymous No.1824225]

>>1824204
>>1824207

thanks, I will rework the circuit and give it another try.

[Anonymous No.1824234]

>>1824225

if you stick a couple of Schottky diodes in series with the 6V supply you'll get very close to 5V.

[Anonymous No.1824271]

I need help guys!
I need to find how USB charging protocol works for Huawei and some other phones work, especially quick-charge. There're very few resources online, so any help is really appreciated.
Also any IC that charge stuff is good for start..

[Anonymous No.1824279]

>>1824271
Pretty sure that should be outlined in the official USB class documents, as found on the official USB website

[Anonymous No.1824301]

>buy LED bulbs for desk lamp
>desk lamp has a dimmer
>eh
>set dimmer to max
>plug LED bulb in
>lights for a min then shuts down with weird coil noise
fuck

[Anonymous No.1824302]

>>1824271
I know that there are chink charger testers that works with those protocols, but not sure if there are any docs online for the protocols.

[Anonymous No.1824332]

>>1817761
>the budget is spent on university education.
>The broken edu system propped up by debtslavery and whales
yup, since (you) stopped thinking i'll stop reading now

[Anonymous No.1824359]

>>1824138
turn it 45 degrees.

[Anonymous No.1824428]

>>1824301
Well shit the bulb is actually dead.
Can a triac dimmer kill LED bulbs?

[Anonymous No.1824583]

>>1818897

I'm using a single relay, similar to what is shown in this picture to allow me to turn off my computer with a remote. I have an issue where it randomly triggers itself, it's definitely not a neighbour because I've walked around trying to trigger someones garage with my remote and it even happens at 3am. The NC is spliced in parallel with the power switch.

I've spliced into the 12v CPU power and put it in parallel and used the case as the return/negative for the relay power. Could this be the issue? Anyone else got any ideas?

[Anonymous No.1824624]

Got a 30mhz scope for cheap, but having trouble finding probes for it. Does anyone see probes that work for an OS-5030 anywhere? Input impedance is 1Mohm/30pF.

[Anonymous No.1824628]

>>1824428
short answer is yes
autopsy of dead led bulb would be of use

>>1824624
pretty much any BNC 1x/10x probe should work since for such frequency it's just passive probes

[Anonymous No.1824632]

>>1824628
Even if it cant get to 30pF? I was looking at these;
https://ast-labs.com/shop/test_cables/bnc/2-sets-100mhz-1x-10x-oscilloscope-probe-hp-tektronix-gray/?gclid=EAIaIQobChMI3fiek-XA6QIVximzAB2zXA_bEAQYASABEgIb8PD_BwE

[Anonymous No.1824770]

>>1824583
relay could be fucked.
try the normally closed side.

[Anonymous No.1824895]

>>1824301
>>1824428
>Can a triac dimmer kill LED bulbs?
Depends on the circuit topology, but for a significant fraction of them it's a yes. But if the dimmer was set near 100% it really shouldn't have happened, unless it's one of those shitty 1/2-wave SCR dimmers.

>>1824632
>Even if it cant get to 30pF
I think input capacitance is reduced by the 1/10 factor too, the actual capacitance of the coax isn't really an issue so long as it's impedance matched properly.

[Anonymous No.1824956]

>>1819522
I wouldn't worry about it... My college textbook doesn't mention anything like this. If I recall, that book had a bunch of printing errors (maybe I found that on his website?)

>>1819535
I think you are right about everything except replace "defined as" with congruent; defined as is :=

[Anonymous No.1824961]

so many projects to do... so much free time to do them too.. but not a single one accomplished yet due to galactic level procrastination

so this is what hell looks like
i don't like it

[anymouse No.1824976]

boomer grandad here, as you note by refusal to use modern resistor symbols.
im trying to design a box to connect a bunch of fuji f-wave panels to a vibrating style water pump. square wave is fine for these.
the panels are 420v open circuit and about 350-380 at peak load. i know i could just feed the power direct into the hv caps on a commercial 2 stage inverter or even a vfd but the reason i want this type of multivibrator type setup is so it will vary its speed to the available light, even if its just one click a second at dawn it will still be pumping some water very slow. at peak sun it should buzz as fast as the pump will allow it.i dont know so much about there newfangled mosfets but they seem the thing for the job and i have boxes of the bloody things in my shed. maybe someone can look over my design or suggest how to make it even simpler. the wierd 2 output optocoupler in my circuit would be home made. i dont know if such things exist

[Anonymous No.1824999]

Anyone help me identify this component?
Not sure if it's a ceramic cap or some sort of varistor

[Anonymous No.1825003]

I just installed one of these mods on my gameboy but the force requited to register a button press is really dissapointing.
Do you think I should tin these with high quality solder to get better button presses?

[Anonymous No.1825018]

>>1824976
>as you note by refusal to use modern resistor symbols
Nah, those are still pretty common. It's your electrolytic capacitors which are more obtuse.
>weird optocoupler
They actually do exist, in the form of analogue optocouplers. They have two phototransistors that are meant to act identically to one another, with one on each side of the HV isolated gap. This way, you can use the LED and the phototransistor on the same side in a negative feedback loop, causing the output of the other phototransistor to be almost perfectly linear.
Though personally I'd just use two normal optocouplers per side, probably cheaper that way. With the LEDs in series, of course.
As for the circuitry itself, your logic is set that the low-side FET will only turn on when panel B is producing current but not panel A, and I assume the high-side FET is the opposite. But how does this lead to vibration? Will both panels ever be on? I think you can ditch the logic gates entirely in favour of a diode, a resistor, and the two optotransistors, using resistor-transistor-diode logic.

MOSFETs are definitely the way to go with your circuit, but note that you've basically made a half-bridge since one FET is high-side and the other FET is low-side. This means you may have to drive the gates differently. If you use complimentary MOSFETs you won't need any floating driving circuitry (15V is pretty good for a FET gate, though I'd avoid putting a large cap across a zener), but in that case you WILL need circuitry to prevent crossover from activating both MOSFETs at once (it wouldn't be pleasant). In practice, this means either having an enforced delay between one transistor turning off to the other turning on, or using a voltage ramp and comparators(?) to enforce voltage hysteresis. Both are difficult because you're messing with two floating power supplies.

>>1824999
Probably 22pF ceramic cap.

>>1825003
I'd first give them a good scrub with IPA and see if that clears things up.

[Anonymous No.1825020]

I powered up an old inspection system that was sitting in storage for years yesterday and it instantly blew a load of caps in the power supply.
It's a fairly old power supply that has different boards slotted into it for the different rails.
All of them are working except the 2 low voltage ones (I assume they're 5v)
So a through hole tantalum blew on both and a few of the aluminiums vented.
I've removed the caps and plugged it in and the input after rectification is sitting at about 23v.
All the caps were rated 35 or 50v.
Any reason they would have blown besides over voltage?
I've replacements ordered.
Could it just be cause they were so old?

[Anonymous No.1825025]

>>1825020
Perhaps the voltage regulation started to fail when too much current was drawn due to inrush current, which caused the voltage to spike after the inrush spike ceased? Try looking at the voltage output with a scope while switching a capacitive load on with a mechanical switch.
I imagine age played a part and potentially lowered the voltage ratings of the Alcaps, but I'm not at all familiar with the ageing characteristics and fail-modes of tantalums.

[anymouse No.1825028]

>>1825018
i might have to make a low current version for experiment, also open the pump to see how it is sprung and if i can either modify it to not need negative to pull the diaphragm back and i can run it on dc pulses, or even get a centre tap on the winding so i can push-pull without a bridge.
i also have a couple of boxes of igbt, discrete and modules but they are even harder to drive. i started building an inverter years ago using a pic and got my drive waveforms, igbt isolated psu board, then stalled at the driver board stage...then the wife hoovered one of the 4 driver chips and i gave up. now the wife has left thank fuck, and i can fill the house with wires and tools that were never permitted.
i seem to remember making some circuit as a kid with a chunky scr that oscillated with quite a lot of oompf.
would love to see some schematics of suggestions. needs to be simple and bomb proof, and if theres sun it needs to run, no matter how slowly. the panels dont put out much amperage and i have 6 up and 2 more to fit. 800w peak. would pay to use 2 pumps in paralel. ihave a 500w and a 250.

[Anonymous No.1825092]

I made a 12v battery because I don't want to actually spend more money.

little case for a 9v at the bottom and 2 AAs goin each way ontop

[Anonymous No.1825106]

>>1824770

It is using the NC side, if I was to use NO the computer would turn off right after turning on. Any other advice?

[Anonymous No.1825110]

>>1825020
I hate old tantalums. Check out shango066 on youtube, he explains it well but the jist of it is aluminium electrolytics dry up over time or lose their "forming", which screws up esr/capacitance and lowers the effective working voltage. Worst case they appear as a dead short in circuit and can explode violently. There is a chance you may have damaged the rectifier, so I recommend you recap and check, and ensure fuses haven't been swapped for a higher rating to mask a problem. Next time use a 40w incandescent bulb in series with the mains input to limit the current if you don't have a variac. In some cases you can restore caps but they're so cheap I just shotgun old shit now. Good luck.

[Anonymous No.1825116]

>>1822853
Nice job, which tubes are those?

[Anonymous No.1825128]

>>1825003
>Do you think I should tin these with high quality solder to get better button presses?

hell, no. and dont use alcohol to clean them as the other dude suggested. alcohol wont remove oxidation, but a pink eraser will.

[Anonymous No.1825141]

>>1825106

most likely problem is electrical infeterence. if your remote uses a code, better set it to something other than all 0's or all 1's. if it doesnt have a code, it should. if you could arrange some kinda software oscilloscope interface, and make a 24 hour long recording in Goldwave, you might catch one of these phantom transmissions, which could come from motors or CB radios, or whatever.

>I've spliced into the 12v CPU power and put it in parallel and used the case as the return/negative for the relay power.

this doesnt make any sense. splice what into the 12V? what's the thing in parallel? where did an idea as dumb as using the case as a return wire come from?

[Anonymous No.1825200]

My 35W4 is still ok, right? This was done with 60V and current exceeded 2A when it reached thermal runaway. The plate was orange, cathode and heater almost white and the glass had caved at the getter. It survived this for almost 45 minutes with 3 tests, current dropping as the cathode was damaged, but the tube never lost vacuum until I dropped it and it shattered, so I guess the glass was weakened as well. So far my best tube destruction asides from a 6BZ7 that melted down spectacularly. If parts fuck me around, they get Widlarized.

[Anonymous No.1825443]

Does anyone know anything about capacitors like this? It's got terminals at both ends, is it just two caps shrink-wrapped together?

[Anonymous No.1825525]

>>1825443
How many? The label leads me to believe it has two seperate components and should have 3 leads.

[Anonymous No.1825535]

>>1825200
>If parts fuck me around, they get Widlarized.

please dont hurt innocent components. save the violence for your pets and children.

>>1825525
>label leads me to believe it has two seperate components

could be a tolerance. 160uF (+ 50uF, - 0uF)
a photoflash typically needs a single store of high-voltage, not two.

[Anonymous No.1825592]

>>1825525
There are the two leads you'd expect on the left, and then two round terminals on the right. The left side is through-hole into a board, the right has two high gauge wires soldered on.

[Anonymous No.1825686]

>>1821072
From page #4 of
https://www.americanradiohistory.com/Archive-Radio-Electronics/90s/1999/RE-1999-06.pdf

[Anonymous No.1825700]

>>1825443
Sounds like a normal axial-lead capacitor to me

>>1825686
Yes I think that's what he's referring to in the very next post: >>1821079
>Found an old magazine from 2002 that covers it (about the only source I could find) And that it's an in house chip

[Anonymous No.1825725]

>>1825700
Four total leads is hardly normal though.

[Anonymous No.1825757]

>>1825725
he didn't explicitly say that though, did he?

[Anonymous No.1825777]

>>1825757
Yeah, it's me and I wasn't clear. Sorry, I explained more in >>1825592

[Anonymous No.1825789]

New

>>1825788
>>1825788
>>1825788
>>1825788
>>1825788
>>1825788

[Anonymous No.1825902]

>>1825535
It was one of those little nightmares that sits right under your nose and mocks you. I was working on a radio that used it and the power transformer kept getting real hot. I was thinking it was cheap filter caps since I changed them twice with no improvement and left the radio on drunk one night. I woke up early morning and noticed a pink/orange glow on the wall from the back of the radio and turned it to discover the fucking 35W4 going thermo nuclear. It tested good in the tester until left on for a couple hours so I later swapped that pos and presto, all good. Surprised the power transformer survived and the tube did as well, but I never forgot the little prick and came across it in my bin the other day, so I took some liberties with it.

[Anonymous No.1825981]

I'm in need of fixing this connector.
It is connected to fuel pump in a car. Its GM car.
I thought it is superseal but I was wrong. This one wider and use different type of wire crimp.
Does anybody knows its name?