/ohm/ - electronics general, real pros ask for a shot of amperage

>pretty sure this is in the wrong board
>the girl in the picture can't even hold the soldering iron properly lol

>>1226752
What, you mean you actually use the plastic grip to hold it? What a wimp.

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>>1226752

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>>1226747
>2.5 is probably a divided ac line sync to enable zero-voltage switching. To protect the pump you would ideally wait for that to cross zero volts then switch.
>4.14 is definitely the switch input. R9 is pulling it to ground. Try shorting 4.14 to 5V.
Thanks, it works. I want to take the leazy mans way and use arduino nano to cotnrol it. Do I need ADC to monitor that sync line or it's enough to digital read port?

Are USB plug sockets safe for use in the kitchen?

>>1226768
It probably dips below ground. You'd need to measure its ac voltage to know how far to pull it up (note the 100kohm resistance already in place). In any case, it's a slow-moving signal so digital probably wouldn't work well.

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>>1226747
>opamps
Since I'll be pumping up to 5W into this transformer, I don't think an opamp is an option, unless I use it to amplify the voltage and put it into a power transistor buffer of some sort. But since the opamp chips in my parts drawer aren't rail-to-rail, I think I'll have to try some sort of transistor amplifier.

> Linear amplifiers are not particularly power-efficient as it is. Now you get to make two.
If I use the transistor for delivering the power then I'll not be draining power from the opamps themselves, but looking at the waveform I'll be wasting upwards of a watt regardless. Is there some way I can use an opamp to make an LC oscillator capable of delivering large amounts of power without dissipating the extra like a linear regulator? Thinking if I used a transistor to amplify the feedback of the opamp I could get it to work. It doesn't have to be rail-to-rail if I use a transformer with higher ratio. But I fear that the inductance from the transformer will mess with the frequency of the LC oscillator if it isn't buffered. Could I use the transformer's primary itself as my inductor?

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>>1226768
Zero-voltage switching is for SSRs but pointless for relays because of the mechanical delay (~5..10ms) and the contact bounce time. The switch is already protected by the snubber network (R1,CX1) and the MOV (VR1).

>>1226776
If double-insulated from the live mains, then yes. Who knows what your local building inspectors would think of it.

>>1226788
>5W
>1A from a 5V supply.
>wasting upwards of a watt
Better than ~72% efficiency at such a low supply voltage is not terrible for linear. Maybe you should try making your secondary resonant?
>not rail-to-rail
If you're using a dual emitter follower, that might not matter. Do mind your thermal bonding of biasing diodes carefully, I say from experience.
>But I fear that the inductance from the transformer will mess with the frequency of the LC oscillator if it isn't buffered.
L1 here seems pretty far off the driven path, so to speak. You'll probably be fine.
>Could I use the transformer's primary itself as my inductor?
I can't think of a way you would get a clean sine wave out of it, but maybe some of the RF oscillators of old offer some inspiration. Not that they were perfectly efficient.

>>1226788
Is this still for the EL wire converter? If so, what's the output power you need?

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A thread is on page 11 and can be replied to, and is at the very bottom of the catalogue, but you can't go to a page 11. Is this normal?

>>1226748
>/ohm/y finger!

>>1226813
I guess I'll experiment with resonant transformers and see if I can get them more efficient and consistent than a linear regulator. Or at least efficient enough to make their lack of consistency worth putting up with. What would making my secondary resonant entail?

>>1226814
Yes. Someone said that EL wire I was going to use was not good for this application, and gave no explanation, but I'm rethinking what I'll use. The Ellumiglow vibrant blue is UV resistant and looks like what I want, but their datasheet shows the exact same infographic of the ones from Adafruit: http://www.ellumiglow.com/el-wire-data
And Adafruit states that the wire will fade if continuously exposed to UV. The operating humidity of <60% also worries me as I live in a city sandwiched between two harbours. I guess I'll see whether the 19NZD for 2.5m from a local Adafruit reseller is any cheaper than the 1.82NZD per foot once I take shipping into account. I should also measure my frame to see if I'll be using a multiple of either unit.
The datasheet is here:
https://cdn-shop.adafruit.com/wanyuPL3.pdf

>>1226837
The secondary side could be an LC tank circuit tuned to the frequency you want to run, which would require knowing the inductance of your secondary and possibly accounting for the image of your primary, but tbqhfam electromagnetism is a bit outside of my skill set. Also, if you're still wanting to do that frequency shift thing, a resonant secondary complex might not be a useful course of action.

Not sure if this is the right place to ask, but is it possible to make a 3.3v fan adjustable in speed? I've soldered a micro 3.3v fan onto a circuit board in a controller I have but want to know if I can also adjust its output or not. Otherwise, I'd like to know if anybody knows a way to do this.

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>>1226872
If I'm not using a relaxation oscillator I'm not changing frequencies, I already know how useless trimmer caps and coils are for anything but radio. I was just thinking that making the primary resonant would be easier than the secondary, but who knows.

>>1226874
Definitely possible, actually quite easy. Assuming it's using a DC motor without any funky waveforms then you just have to use a normal PWM circuit. A PWM circuit, or pulse width modulation circuit, uses a comparator to compare the voltage across a voltage divider with a generated triangle wave. If the triangle wave is higher for a particular moment (or lower, depending on how you set it up), the comparator will output a logical high, probably 3.3V in this case, and when not it outputs a logical low. The voltage divider is usually a potentiometer, or a variable resistor with a set value and a wiper in the middle that determines how much resistance is on either side of the centre contact. Since the total resistance is constant, by putting each end across a voltage source (probably 3.3V) a constant current flows. The voltage at the middle is determined by the resistance relative to ground by V=I*R, so a higher resistance to ground means you get a higher voltage. If you have a 3.3kΩ potentiometer and have it tuned to be 1.3kΩ to 3.3V and 2kΩ to ground, the output voltage will be 2V. Now comparing a voltage to a triangle wave can be visualised by drawing a triangle waveform with a line at some height through it, representing the divided voltage. When one is higher you get 3.3V out, and when the other is higher you get 0V out, so you can see that the output will be a square wave with a duty cycle, or "on-time:off-time ratio", that varies with how you turn the potentiometer knob. By putting the comparator output into a transistor you can switch the voltage to the fan itself, and vary the time for which it is on and off. See pic related for a circuit.

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Hi friendos,

I am wanting to build an amplifier and i have 0 electronics knowledge. Here is what I got:

An old Topping Amplifier box with all RCA/Speaker terminals and shit that no longer works.

I have bought a Sure-Hifi Amplifier board: https://www.parts-express.com/sure-electronics-aa-ab32189-2x100w-tda7498-class-d-amplifier-board--320-303

What do I need to turn that Amp Board into a fully functioning amplifier with the stuff I have in my possession? I've got a solder but thats probably all I have.

I noticed that the board doesnt have a knob.. so will I be able to use my existing toppings knob components to control the volume?

All I want is to control volume with this thing as well as connect banana plugs into it! What do?

>>1226935
>I am wanting to build an amplifier
>i have 0 electronics knowledge.

What is wrong with you?

>>1226935
install gentoo

>>1226956
yea I just want the right equipment to get started theN I can learn along the way.
anyway fuck at this rate I am gonna have to cancel this order because I don't know if I can put a knob in there..

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>>1226964

of course you can put a knob in it. it's really simple, coz you just ask google ''adding volume pot to amplifier'' and it spits out results like this. (pic)

>>1226894
At the low supply voltage you have, I imagine it would be harder to make the primary side resonant. Since your secondary is all passives and presumably of a relatively constant impedance under most conditions, you just need a cap to tune it and thereby open up some degrees of freedom on the primary side.

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BTW, everyone who experiments with I2C or other medium-speed serial buses and doesn't have one of Pic related is crying.
So simple, yet so useful.

>>1226971

would it hurt to name your pic properly, asshole? or include part # in post?

>>1226972
I made it while drinking this evening out of a long-tail socket header, a scrap of proto board, a few colored headers, and a few pieces of wire.
The WeMos D1 mini is stock.
Nyaa.

>>1226970
But it will have to be driven by the primary side, so I'm wondering how I'll be getting feedback. I think the super high voltage transformers people make use another feedback coil to trigger their transistor, so I could try doing that. It might turn into an RL relaxation oscillator, whatever that would look like. Capacitive coupling transformers when.

>>1226969
thanks man, if I don't put in a stereo pot, and then I run some music with the amp, will it go full blast? I dont want full blast.. dirty watts into me speakers

>>1226977
>Capacitive coupling transformers when
When you wind them wrong.
I'd just empirically tune the thing until I got the level I wanted.
Also optoisolators aren't that bad. There are even some with anti-parallel LEDs for ac sensing.

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>>1226985
No, I meant a transformer that works by having two coupled capacitors as opposed to two coupled inductors. Their geometry doesn't really make it possible, but you could probably make a very inefficient one.

>pic related
Looks like this project just got a little more fun...

>>1226978
>will it go full blast?

of course. pot allows you to adjust between 0-100% of input level.

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>>1226987
This is what you get from the EL-wire dealer for 5 mon€ros.

>>1226962
>install gentoo
>this solves everything

>>1227012
>>install gentoo
>>this solves everything

sure, if your problem involves computing. but what if you're problem involves painting a ceiling?

>>1227030
Dual-boot Arch with I3

>>1227034
>Dual-boot Arch with I3
>this works every time 97% of the time

>>1227000
Yeah, the idea of finding what circuit they use at the moment hit me as a pretty good idea, but there seems to be no two similar circuits when I search "el wire driver circuit" on google images. If worst comes to worst I can always step the voltage up to 100VDC and switch that with a FET.

>>1227140
>but there seems to be no two similar circuits
So you have plenty of options to choose from. What's the problem?

>>1227150
The problem is there's too many circuits to try and test in spice, figure out which one works best there, and then figure out how they'd actually work, and compare and contrast all their ups and downs. But at least I am somewhat limited by not being able to select circuits with ICs that I have no access to.

Has anyone ever requested a sample from Kemet? I want a capacitor for a power supply that I have, but I do not want to order the cap due to shipping.

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>>1227140
>100VDC and switch that with a FET
Switching kills EL wire, sine required. Audio transformers are hard to come by, but what about a tiny mains transformer, (12+12):240 = (5+5):100 and tuning the drive side?

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Every time I plug a servo in the arduino it nudges a little as if taking a starting position. Is this position set? Its just that I have a servo connected to this contraption and the degrees from 100-180 should be off limits since there is a physical limit to the servos movement. If the servo jumps to that zone when powered shit will hit the fan. Can anyone help?

>>1227275
Using a mains transformer is my go-to because hand-winding is a pain in the arse, and that's a really interesting looking circuit. Is it a sine generator, or something close enough? Finding a transformer with that kind of ratio and centre-tap on it might be tough, but rewinding the primary/repurposed secondary might not be too much of a task, and it's probably necessary to get the ±5V precision at these frequencies anyway. I assume the frequency is set by the capacitor?

>>1227283
If you plug it in it may power up before getting any signal and try to move to one extreme. Maybe a digital servo that can ignore no signal or something i don't know lol
Just put a physical stop on the servo maybe, belt and braces if anything

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Is it possible to use rtl2832u+r820t2 (or some other sub 200$ sdr) as a cheap terrestrial and sat tv test rig?
So i basically need a real time fft of 50-900mhz and 1000-1850mhz bands with 20dB dynamic range at 30-120dBuV levels.

>>1227302
It's a pretty neat circuit, called a self sustained push-pull converter. Pretty close to sinusoidal so long as the primary and secondary are tuned reasonably close in frequency.

>>1227322
Total bandwidth you can see at a time is ~2.4MHz, so if you're looking for a full span like that, not possible. R820T2 with experimental drivers can cover 13-1864MHz, although at the extremities it isn't quite linear as it's moving the intermediate frequency on the RTL instead of moving the tuner.

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>>1226748
Hey /ohm/ help me out.
I have this prototype perf board with all separate holes like pic. I have a few sockets for ICs and two pins show there is 800K ohm resistance between each. But there are no connections at all between these two pins. Is it a bad socket, dirt causing allowing current or something else?

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>>1227302
>frequency is set by the capacitor?
That's the idea. I have a small (15+15):230 EE20/6 transformer and the L meter says 1.8H for the 15+15 side, which means 14nF for 1kHz. Sounds promising to me. The load side will certainly need a series C to tune it to the same frequency. The EE20/6 transformers are also available as 6+6 and 9+9 for about 2€.

>>1227331
800K with just the socket in or with chip? If with chip, that's probably how it should be.

If just with a socket, probably something on the surface, run a knife between the affected pads to see if that clears it.

800K leakage wouldn't be a huge deal for most circuits you'd use a perfboard for anyway.

>>1226987
I've seen optoisolator designs that do that to galvanically isolate signals, but not for power. It appears that most hobbyist EL drivers don't bother with isolation fwtw.

>>1227331
Humidity, or flux residue? Try washing in isopropanol, rinsing with water, and baking them at 850C for an hour or two to dry.

>>1227330 But internet says that it can retune up to 40 times a second.
I think it might be okay to have a crude fft updates at 0.5hz or wait 10 seconds for a high quality graph.
Is there any software for it?

>>1227347
Found this zolli altervista org/rtl_sdr_wide_spectrum/, looks like that'd do what you want if you don't mind the slow updating. Linux only if that bothers you.

>>1227346
>>1227345

Thanks for the tips. Yeah it's with no chip in socket. All others are fine. Just these two.

Will try cleaning. There is some small amount of flux residue. Only have rubbing alcohol at the moment.

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Anyone tried making their own scope from sound card? There is old compaq armada m300 with damn small linux collecting dust in my closet and I wonder if it's possible to make cheap scope out of it.
Software:
http://xoscope.sourceforge.net/
Hardware probe:
http://xoscope.sourceforge.net/hardware/hardware.html
Notebook:
https://www.cnet.com/products/compaq-armada-m300-11-3-piii-win98-64-mb-ram-6-gb-hdd-series/specs/

>>1227369
It'll be shit, you will have better luck with those 2$ stm32 boards from aliexpress, or even better, stm32f303 series micros.

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What is a common push pull transistor array or shift register? I can only fill common cathode arrays like the ULN2803

I need the outputs to be either at 0 volts or at 30 volts.

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>>1227380
>push-pull
They call it a half-bridge when switching. Try the TI DRV8844 for 4 outputs up to 60V or 2A.

>>1227380
What are you driving on the outputs?

Hey /ohm/, got any discord link?

>>1227405
A half bridge would work fine, except I need at least 8 outputs per IC. I think the correct name for what I'm looking for "8 bit high voltage (<40v) source driver"
>>1227410
I'm driving a VFD display, i need to dump 25-30 volts and some milliamps into each segment. I found a neat source driver with latched outputs http://www.ti.com/lit/ds/slvs867b/slvs867b.pdf but the output voltage only goes up to 15 volts, it would be nice to find something similar that can withstand around 60 volts.
Another option is the UDN2987 or the A2982, but I'm having trouble finding where to buy them.

>>1227431
There's a /diy/scord, but it's as slow as the board.
https://discord.gg/sm5rh2

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>>1227460
Like Pic related, right?
If you don't need a lot of current, TBD62783 is an octal logic-level source driver that allows up to 50V and 500mA. $1 at Digikey.

>>1227464
That's pretty much what I'm looking for.
Also, is there a shift register version? Like the TPIC6C595 but sourcing current instead of sinking it?

>>1227460
For a VFD you can use open collector driver + high resistance pull ups. Segment currents are typically in the tens to hundereds of microamps, so the losses of sensibly chosen resistor are tiny.

>>1227466
How about the MIC5891?

does jameco also have high priced shipping like adafruit? fucking adafruit's shipping takes 6-8 days and is still $10

>>1227478
It's right on their site, anon.
http://www.jameco.com/webapp/wcs/stores/servlet/PageDisplayView?langId=-1&storeId=10001&catalogId=10001&content=shipping

>>1227487
thanks man, don't know how I missed that

>>1227466
Maxim makes some shift register ICs specifically for VFD driving, for example MAX6921 and MAX6934.

>>1227475
Yeah, that'll do. Thanks anon.
>>1227516
They're friggin expensive at 6$ each considering I need at least a couple of them.
>>1227467
I thought about doing this, but I'd rather keep it efficient, also I would have to add a lot of resistors.

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>>1227569
>I would have to add a lot of resistors
No pulldown = fast ON slow OFF.
Resistors back to haunt you?

>>1227569
>>1227475
MIC5891 needs pull down resistors, open collector needs pull up. The expensive special chips often do proper push pull.

The segment pull up/down take fuck all power compared to what you're burning in the filament.

>bought a really good secondhand monitor for a really cheap
>stopped working in less than a week
>bought a second one that is even better and cheaper
>stopped working in less than a day
>its the fucking capacitors but I change them to save my life
existence is truly hell

>>1227625
meant can't*

Does any one know a good source for digitalized Data Books? I want some old Philips, Motorola and other ones.

>>1227772
Dunno about good, but bitsavers.org is worth checking. Also archive.org, which includes at least a part (if not all) of bitsavers' stuff.

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Wat do?

>>1227784


empty your mom's bank account and put all her money on red 13 and let it ride for three spins.

she will love it if you win.

What is the best Arduino Uno clone?

>>1227824
>the best Arduino Uno clone?

Probably any of them. It's just making a board and soldering. not hard.

I buy shit from Thailand (futurlec) and once in a while I have to fix a bad solder joint but the boards are good and cheap.

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whats the point of having raising the voltage and putting capacitors in between like this before rectifying it?

>>1227866

those arent transformers, they're chokes used for reducing noise between the circuit and the 120V line.

My friend wants to put a new Arduino display on a graphic equalizer, we have everything figured out and it works fine, we just need to power it. Can we take a 9V 300mA wall wart and splice it off of the 120v in the equalizer and then keep the wall wart inside the EQ? And have the output go to the Vin of the Arduino? Or is this dangerous or does it cause interference?

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>>1226837
Hey m8. What are you using the EL wire for? Asking because this strokes my autism.

>>1227888
Ignoring the sanity of the project overall, did you check the power supply board to see if there was a suitable dc voltage available for you inside the box already? The wall wart might end up being duplicated effort, and you probably don't want it banging all round in there.

>>1227891
Not that anon here, but the application was bicycle visibility.

>>1227896
Nope, nothing usable, normally I would use voltage regs off of op amp but I looked at the schematic and there's nothing suitable

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>>1227896
Hmm, I wonder if he has looked into side emitting fiber optics. I'm not sure if it fades in the sun over time, but it is brighter, doesn't fade over time, and lower voltage. Pic related.

This is really?

>>1227891
I like Tron. I want a light bike.

>>1227900
I saw "laser wire" on the Ellumiglow website, and saw that it cost a few hundred dollars to get started, so I ignored it, but I didn't check AliExpress or eBay for their prices. Looking now I see their prices aren't overly good and their light emission looks less even than the EL wire, and I do have a bit of a thing for electroluminescence. But if anyone has any recommendations for either product I'm happy to hear you out.

>>1227866
They're line filters to reduce how horrible the current waveform of bridge rectifier into capacitor looks.

Is a tip31c a suitable replacement for a d313 transistor in a power supply?

>>1227925
Looks like it should be alright. Only thing that I spotted that's quite different is lower typical current gain, so would want to test that it still holds regulation properly at the limits of the supply.

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>>1227909

I saw laser wire, and I agree the price they want for what it is, is complete garbage.

Side emitting fiber optic != laser wire. Two totally different technologies. SEFO is cheap, and readily available on ebay. It's brighter than EL wire, lasts longer, can easily be replaced, and is cheaper.

>>1227899
>Nope, nothing usable

betcha it has some diodes and filter capacitors with around +15V on them. you can tap a 5V regulator into that, assuming you dont draw too much current.

>I looked at the schematic and there's nothing suitable

show us and we might do better.

tapping into the 120V should be a last resort, but doable if you isolate things well, and NEVER show it to anybody.

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>>1227930
They're really that different? Laser wire looks like another brand name of the same thing, though I'm not sure how much of a difference using a LASER diode has compared to using an LED. The stuff I was looking at on the China express was SEFO, because they don't sell anything called "laser wire". SEFO is about twice the price of EL wire, but far easier to drive.

Also, what do you think about pic related? Found it on AliExpress and I think it looks like an accident waiting to happen.

>>1227941

Really, I found EL wire was more expensive than SEFO.

Also, that looks like an accident waiting to happen, or people being really fucking pissed at you.

>>1226748
i have an older laptop battery that i think i discharged too far to the point below which it will charge in the laptop. how do i identify the power pins and safely charge it up with an adjustable power supply? its an hp probook 4535s

>>1227942
Could you tell me what keywords you use to get SEFO? "SEFO" or "Side Emitting Optic Fibres" gives me next to nothing, and" LED fibre optics" gives me those bundles of 50 tiny fibres that really don't suit my application.

>>1227963
Try side emitting fiber optic

http://www.ebay.com/itm/1-5W-DC-12V-car-use-home-use-car-light-side-glow-fiber-optic-light-illuminator-/261876744899?var=&hash=item3cf91202c3:m:mVGLvkL3F30r9cJHCfv4igw

http://www.ebay.com/itm/3mm-5Meters-Car-Home-LED-Lighting-Decoration-Side-Glow-Fiber-Optic-Cable-Clear-/172796084170?hash=item283b72ffca:g:12kAAOSwbYZXV8y6

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>>1227956
>safely charge it up
Unless you can watch the cells themselves and be sure they're not bulging or hot, you really can't. The theory says that you supply a very low charge current, say 1/100C, until it gets back above 3.0 volts at rest, carefully monitoring all the while for anomalies. Personally, I'd just break down the pack, find the good cells, use them for other applications, and recycle the bad ones.

>>1227991
so being a 10.8v 6 cell lithium pack, what is the voltage i would set it to charge at? and current set to what, like 100ma or something?

>>1227995
So, 3S2P.
C is the rate of current at which a battery would be completely filled or emptied in 1 hour. In other words, the Ah rating without the h.
3.1V x 3 = 9.3V
4.5Ah / 100h = 45mA
As to finding the correct pins, web search. You may or may not be able to wake the battery back up without opening it.
Here are more precautions and finer points http://www.batteryuniversity.com/learn/article/low_voltage_cut_off

Is there an audio leveling circuit that is suitable for music? It seems like most are just suitable for speaking. I guess there are issues with distortion and reduced dynamic range that make them undesirable in higher fidelity audio systems.I was just wondering if there was some other topology I wasn't considering besides the peak detector and variable impedance diode method.

I need to make a counter with 74ls93 with the following sequence 10-43, first of all is needed to simulate (Proteus or other) to begin to connect.
How i start?

>>1228015
How about replaygain?
I think operational transconductance amplifiers are ideal for this sort of thing.

What stepper motor driver bridge would you guys recommend?

>>1228051
Specs?

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>>1227964
That stuff uses high-power (1.5W or so) LEDs, right? Would it be possible to hack some RGB LEDs in their holders instead?nI really like the idea of red, but I don't think it's legal to have red lights anywhere but the back, so I'd like to be able to change them when I'm on the road (there are a bunch of footpath-style bike paths where I live). I'm still not sold on them because they change intensity as you bend them (and my soviet electroluminescence fetish, see http://www.155la3.ru/electroluminescent.htm). So I've never bought stuff from ebay, and they say free shipping which is nice, but the quantity is misleading. Nowhere on either of those listings does it state whether buying a "quantity of 3" would mean purchasing a single light emitter and 3 times the length of tubing, or simply three lots of emitter and seperate lengths of tubings. Another problem is that I'm not able to cut the length and continue it elsewhere without buying or making another emitter; I'll have to keep it continuous or put heat-shrink over some parts which feels a little wasteful to me.

If I'll have to buy 2-3 emitters that will put me up $10-15, and having to buy the tubing as well for $4 a foot, then it appears pretty costly. Since I'll be wanting about 6m of the stuff in various lengths, getting that with this side-emitting fibre optics will cost me at least 90NZD. On the other hand, EL wire will drive me to about 40NZD, plus say 20NZD for the transformer and other coils and caps, and I've already got a bunch of passives, so I'd say that it's the go-to decision.

Also I really want to make something with pic related, so I want to get familiar with the tech.

>>1227275
Wait, assuming I put another (10* EL wire capacitance) capacitor in parallel with the load, wouldn't almost all the current be used by that capacitor and not go through the EL wire? Would this make the EL wire dimmer or am I misunderstanding reactance? I'll be simulating it soon, not sure how well it will work though.

I'm putting a 12v cigarette lighter socket on a motorcycle for convenience. inb4 bla bla SAE plug.

Would 16 gauge wire + a 5a fuse be an alright idea? Everything points to yes

It goes battery > fuse > relay (to headlight low beam) > socket -> ground of course but I don't know what the fuck I'm doing and don't want to burn a wire before I burn a fuse

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...I'm not sure if I want to do this anymore...

I think I'll just look like a retard. As in, more so than usual.

I might put reflective tape around the place instead. Also maybe fluorescent tape with UV LEDs every now and then could be interesting. Well now my power supply is just a prebuilt constant current PCB and possibly a transistor-based constant current driver for the rear lights. At least the cells should last a while. I just converted their Ah value to coulombs by 3600 factor, multiplied by their voltage, divided it by the power (~1W), and divided back by 3600 to get hours from seconds, and I feel stupid, but it tells me over 50 hours. Assuming these cells aren't complete garbage.

I'm still considering using a red EL panel as a rear light since it will give diffuse light, but I don't think it will be any better than a few red LEDs behind some sandpaper-frosted acetate sheets, which will probably also have a little directionality, which will probably be nice. The LED method is less space efficient, but I should have enough space under my bike seat for either method.

I think I'll use Jubilee clips to keep the lights and batteries on instead of trying to perfectly shape the wooden housing around the handlebars and seat-bars. Maybe I'll use obscure fasteners if possible too, for security. When it comes to using Jubilee clips, do they move (and provide force) continually as you tighten them, or do they more increase in increments? Never used them because I always searched for them under the name "hose clamps" and couldn't find them.

>>1228122
So you put the socket in series with your relay so that it's enabled when your headlight is low? You should probably draw a diagram, and if I were you I'd wire it off the ignition relay instead, so you can use it without turning on the light, but I have no idea what common practice is for automotive stuff. Depending on what you plan on doing with the socket, you could probably get away with a smaller fuse and thinner wire, but better safe than sorry. Just make sure you don't have any devices that will instantly trip the fuse.

>>1228125
>continually as you tighten them
This, if well-constructed. Add some rubber to make the inside less slippy.

>>1228132
The low beam comes on once the bike is running, not just once the key is turned, and is easier to splice into.

>>1227366
>>1227346
>>1227345

It's working. I reworked things a bit and cleaned it and my silly timer is now working. I only had telephone wire so the job is pretty shitty.

>>1228066
Any generic nema stepper suited for 3d printer

>>1228134
I've seen rubber as described on other bike light clamps, would a section from an inner tube work? Technically the tube in mind is still functional, but since it gave me 6 punctures in one year I don't want to start trusting it any time soon; it should make a worthy sacrifice. Any other recommended sources of rubber while we're here? Would a wrapping or two of electrical tape suffice?

>>1226971
>node and a bunch of pin headers
you are so fucking amazing

>>1228122
>16 gauge wire
AWG16 is the "magic 13" wire: diameter 1.3 mm, cross section, 1.3 mm2, resistance 13 mΩ/m, good for 13 A at a (conservative) current density of 10 A/mm2

>>1228184
>would a section from an inner tube work?
Yes, better than tape, but first remove all talcum from the inside.

>>1226935
>An old Topping Amplifier box with all RCA/Speaker terminals and shit that no longer works.

my 200 dollar topping dac broke after a year. still mad i bought chi fi trash.

>>1228188
Most of those little chink modules are equipped with male pin headers, and most solderless breadboards are equipped with female sockets. Power and data on pin headers that can be plugged into a breadboard is pretty handy. Beats running out of male-to-female jumper wire.

>>1228184
>Would a wrapping or two of electrical tape suffice?
ask
>>1219256
Butyl rubber is great and stands up well to weather. Electrical tape might be a bit slippery on the outside, as one would want when pulling cable.

>>1228371
>slippery on the outside
Not only that, the adhesive ages and slowly creeps under load, bike light moves down. What also works well is self-fusing repair tape, the one you first stretch and then wrap around.

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>>1228110

I thought about 3D printing a holder for the SEFO and an RGB since the LEDs they come with are kind of expensive for what they are. I haven't experimented with this yet.

I understand the EL fetish, I have the same for anything glowy, especially old Soviet surplus shit. Pic related.

>>1228371
That thread still exists?

>>1228406
That fusing tape costs an arm and a leg though, and I'd prefer something removable, but that won't fall off if I take the light off, so a light adhesive tape is ideal for me. I'll see if there are any rubber grip tapes, for similar purpose to those sandpaper grip tapes that is applied on stairs. But otherwise, if I stretch electrical tape tight enough I think I could prevent the clip itself from slipping, and remember the clip will be putting pressure on the tape itself. My handlebars are black anodised aluminium, so they're definitely grippier than a glossy surface too.

>>1228425
While I'm of the opinion that hot-cathode < electroluminescence < cold-cathode, I think we all have a bit of a retro thing. I can definitely see SEFO being a good option if you just use normal LEDs that aren't $5 each, though I don't know what kind of lumen output is required. Maybe a laser diode would do interesting things. Regardless, I think I'll be going the way of retro-reflective tape instead of glowing wire, especially since the stuff won't be visible in the day time anyway. Now I guess it's time to finalise the simple LED layout, test the solar panel, and figure out the housing designs.

>>1228435
Yes, still exists.
Yes, really, inner tube rubber will be a much better and grippier interface between the tube and the load.

>>1228446
I just don't want it falling off when I want to reposition the light. I guess a touch of CA glue would fix that?

>>1228458
CA, hmm? I don't know about that. You could use tube patching cement to lay down a thin strip of rubber as a rail on each edge. You can then loosen the clamp slightly and not risk the strip bailing out. You don't necessarily need to take the whole strip or the rail strip all the way round the tube, either. Perhaps just cutting it wide and folding in the corners would be enough to retain the lamp.

>>1228461
>folding
I don't think the rubber will do that plastically, but if I patch it in place with the rubber cement I think it will work.

>find cool looking Great Scott video where he makes an FM receiver
>first video is for a proof-of-concept design with bad audio quality and hot glue everywhere
>actual serious video just uses an Arduino and prebuilt superheterodyne receiver
This isn't an easy road. I guess I'll start with a simple FM receiver and try to comprehend the improvements made upon it.

I was just reading how an American POW in Vietnam made a foxhole AM radio receiver with an oxidised razor blade, toilet tube, and scavenged wire. Also how crude diodes were made with improvised metal-oxide junctions between copper metal and copper oxide, though I wonder if they'd work better than a cat's whisker.

>>1228607
An AM receiver is a few orders of magnitude simpler than FM.

>>1228607

while you're building your FM radio (that you can literally buy for $1 at the dollar store) billions of interesting and innovative gadgets are waiting for some diy-er to come along and make them see the light of day.

>>1228612
>muh innovation
Go away, CTR. Bikeanon owes you and your attention-deficit neoliberal society nothing.

>>1228614
>Bikeanon
Less than 1/2 of my posts here on /ohm/ are as bike anon, but what gave it away? My desire for this board to be faster/excess of spare time? Or my curiosity/naiveté?

>>1228612
Oh and while I do love the idea of electrical innovation, how can I know where we're going if I don't know where we've been? I plan on steadily following the roots of electronics, specifically radio.

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Hello, I want to build a controller for SDVX with Arduino according to http://sdvxii.pancakeapps.com/LEONARDO. The problem is I want to use big encoders, pic related, and on that website it is only shown how to connect the small ones. How to do that? Is there any difference?

>>1228641
>The problem is I want to use big encoders, pic related

type, part number, or model?

>>1228648
http://www.ebay.com/itm/NEW-Incremental-Rotary-Encoder-600p-r-6mm-Shaft-5-24vdc-/121568516551?

Ok, that's the fourth one listed on the other link, so it should work fine, but you need to look at the specs and see what changes to make to the code, oops, I meant the changes to the sketch in your sketchbook.

Hopefully someone will show up and walk you through it. I'm not familiar with encoders or I'd give some tips.

>>/g/61928360
next OP?

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>>1228666
fucking knew i was gonna fuck that up

>>1228667

>>>/g/61928360

some autist should add an auto-correct feature to 4chan code to fix that, or to nag you when you go to post. Clippy would be nice for that.

>>1228670
also when you write something like "pic related" but you don't have an image selected.
Perhaps once Hirohito will take a break from selling user data to the FBI...

>>1228641
>Is there any difference?
24PPR encoder has mechanical contacts and (probably optical) 600PPR encoder has NPN open collector outputs and needs 5V supply. Same A, same B, same GND. If you want to be a dingus you connect A or B directly to 5V and buy a new encoder, it says. Turn it slow or your lolduino will choke.

>>1228690
>Turn it slow or your lolduino will choke.

aren't some of them up to 20Mhz or so? and many operations are one cycle, most are 2 or 3, so you're talking 10 million ops per second. at 1000 rpm 600ppr is just 1200 x 1000 = 1.2 million pulses per minute, or about 600 ops per pulse.

of course I'm ignoring whatever else the AVR has to handle, but if the code is tight they can do a bit of work.

>>1228690
So do I have to buy something besides Arduino and encoders?

>>1228697
Dunno, wasn't there a BOM in your link?

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> tfw all these tools but can't make a GF

>>1228703
It says how to connect 3 pins to Arduino but the optical ones have 4 wires instead.

Is there something like an ULN2003 but based on MOSFETs instead of Darlingtons?

I was looking for a software driven USB oscilloscope under the $200 range. Not looking for anything fancy, just enough to use while repairing some Commodore 64s and 386/486 motherboards I've got laying around.

Anyone have any good experiences with USB oscilloscopes?

>>1228736

this is gotta be a troll
- USB scopes are absolute crap. get a cheap Rigol or an Hantek DSO5072P
- unless you run a museum, 386 stuff and C64 stuff is completely worthless

>>1228759
Thanks for the recommendation, didn't realize I could get a new stand alone unit for that cheap.
And why the lack of love for old hardware?

>And why the lack of love for old hardware?

no interest in running Windows 3.1 or Chopper Commander.

>>1228772
>Windows 3.1
3.11 WFW is the best

>>1228764
>And why the lack of love for old hardware?

not that guy, but you can buy a far better computer for 20 dollars. the old shit is only useful for legacy software that somehow has stuck around and for nostalgia freaks. I still struggle with some dos shit that I wrote about 20 years ago but have to maintain because moneybags won't upgrade the computers that run it. Turbo Pascal used to be awesome in its day, but goddamn it's like plowing a field with a butter knife compared to modern environments.

And as for the nostalgia freaks, it's like the guys who actually want to play the old Atari garbage. Beats me. It's not like listening to old music, unless you're listening to an Edison wax cylinder recording of Billie Holliday's grandmom.

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>have this retail battery pack meant for RC goggles
>takes 2 18650 batteries and puts them in series
>designed to be strapped to the head
>shit is kinda uncomfy so decide to lengthen the cord so i could just keep it in my pocket
>find out that when rapidly moving the pack (such as grabbing it from the pocket hastily) the springs inside that hold the battery give away, compress and opens the circuit for a split second.
>goggles really dont like when power is disconnected even for a split second

so how do i fix this? add a cap and a inductor somewhere?

>>1228772
>no interest in running Windows 3.1

windows 3.1 is one of my favorite "bill gates is an incompetent shithead" stories. the first mac came out in 1984. not long afterward microsoft came out with windows 1, which they gave away for free if you bought a mouse. I suppose there was a windows 2 and a windows 3, but the first version that barely worked was 3.1 which still sucked.

they didn't come out with something remotely like the mac until windows 95. 11 fucking years folks. and even then, if you bought a mac magazine it was full of articles about how to do this cool thing and that cool thing. PC magazines were full of articles about how to fix this pile of shit and work around that pile of shit.

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>>1228711
www.ti.com/product/TPL7407L

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Supercapacitor question.

I have two car cams that have never shut down properly, meaning the last and most important file in a wreck is never closed out correctly. Today I took one apart and removed the supercapacitor and put a solid 5v supply on it, and now it remembers the date and shuts down properly, implying that the supercap was either no good or was not being charged properly.

Assuming it's either faulty caps and or too small, what would you expect to happen if I took the Kamkap 5.5v 1F out and put a Kamkap 5.5v 4F in? they're dirt cheap on alibaba: the 4f is 80 cents each.

It seems unlikely that both cams have defective supercaps, so I assume they either underdesigned the cap capacity or the charging circuit sucks.

I checked the camera and when the main power goes away it draws 0.5 amps for 10 seconds from the shutdown power source, which is a hell of a lot of power to close out writing a file to an SD card, it would seem, or maybe that's normal.

tldr; if i change a 1F supercap to a 4F supercap should I expect smoke and flames or does the charging circuit not care about farads?

>>1228805
Amiga's Workbench blew them both out of the water.

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>>1228803
nvm i was too lazy

i added solder to the nipple to make it more higher and i added some hotglue to the spring to make it alot more stiffer

its nasty as fuck but it works very well now

>>1228809
Go for it. It's basically like putting a bigger battery in there. The only thing you really have to make sure of is that the voltage rating of the new caps match or exceed that of the original ones.

>>1228809
it could break it but it won't

>>1228821

thanks. they're both 5.5v so I'm gonna try it.

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>>1228615
Bikeanon appears to enjoy constraints.
>>1228617
As do you. Of course, where we're going may or may not have anything to do with where we've been. It's definitely good to learn first principles, but one can certainly go too far down that garden path, Pic related.

>>1228677
There's a Thunderbird addon that warns on missing attachments. Maybe the 4chan-x dude could do it.

>>1228693
You'd probably want interrupts for an encoder. I know I would.

>>1228736
Do you want a logic analyzer instead? You can run a BeagleBone Black as a logic analyzer, $60 + maybe level converters.

>>1228759
Tell the niggers chopping up old C64s for their SID chips and reselling them for $80.

>>1228819
There's nothing wrong with a mechanical solution to a mechanical problem.

>>1228809
>0.5A for 10s
Have you tried a faster SD card?

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>>1228822
>it could break it but it won't

you have a way with words. thx

lol captcha

>>1228836
>Do you want a logic analyzer instead? You can run a BeagleBone Black as a logic analyzer, $60 + maybe level converters.
Never used one although I've always thought having one would be really neat, even if I would be a bit in over my head at first. Can they really be had for that cheap? And if chance you would know a resource for making good use of such a device?

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Let me preface this by saying I know very little about vacuum tubes. I bought ~800 because they were very cheap and then purchased a digital tester so I can resell them. The problem is that the tester reads the current as 30%-50% lower than spec for every tube I have tested thus far. I highly doubt they're all defective; they came from several sources. How can I go about determining what the issue is and how to resolve it?

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>>1228805

>>1228840
It's a question of what you want to measure. Think of a logic analyzer as a scope with lots of binary-only channels and slightly more sophisticated triggers, and it should be fairly intuitive. If you really want to look at the shapes of signal edges and such, or troubleshoot the analog circuitry, the scope is the right tool for the job. But if you're looking for logic errors, such as a misbehaving PLA, the logic analyzer would reveal that quite readily.

>>1228847
There's a good chance that those tubes were very cheap because they were substandard. Buy a known good new tube from a guitar dealer (~$30) and see how it reads.

>>1228861
Nowhere near me sells tested vaciim tubes, but I just tested a pristine NOS tube that read 25% low. As I mentioned, these came from 3 sources so I find it extremely improbable that they're all broken.

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>>1226748
sup, /diy/. i recently bought myself an action cam, the Eken H9. i like the cam, but the microphone is pure garbage. i saw it could be easily replaced by a bigger microphone. never soldered something and i need some advice to not fuck it up. i bought these microphones cheap microphones. can i still expect a quality increase or do i need some more quality components like the second ones? and is there anything i could mod when i'm already opening the cam? pic is the original microphone

https://aliexpress.com/item/Free-shipping-18pcs-9-5mm-Dia-MIC-Capsule-electret-condenser-microphone/32350428520.html


https://aliexpress.com/item/2-pcs-lot-WM-54BY-Omnidirectional-Electret-Condenser-Microphone-Cartridge/32541105995.html

>>1228868
You should check that all your power supplies, especially the heater supply, are within the correct range for the tube, at the tube, when the tube is connected. it's possible they might be weak.

>>1228871
>easily replaced
>never soldered something
No.

>>1228868
Either all tubes are weak or your tester is not correctly adjusted. A tube, its data sheet and a multimeter can settle that.

>>1228847
What tubes? Just out of curiosity desudesu.

>>1228884
>>1228890

heater/filament reads 6.33, supposed to be 6.3 +/-10%
plate/cathode reads the correct voltage, I guess I just need to test plate/grid for grid voltage?
I have tested multiples of each of these models:
12AX7
6BL7GT
5AH4GT
6SL7GT
6J5G
6BD5GT
The plate current is always below spec.

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I bought a chinkshit camera, and the microsd card will not insert all the way into the slot and click into place. I tried using enough force that some of the paint on the SD card started to come off, so I'm confident it's not me being a pussy.

Is there any way to fandangle my way into getting this slot to work, or is it fucked? I kinda need this camera to be up and running by the AM.

>>1228898
>the microsd card will not insert all the way into the slot and click into place
have you tried turning it over?

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>>1228897
ECC83=12AX7, grid directly grounded.
Heater: apply 12.6 V across pin 4 and 5
or connect pins 4 and 5 and apply 6.3 V across pin (4,5) and pin 9
Set V_anode = 250V, set R_cathode = 167 Ω (100+68)
expect V_cathode = 2V
Set V_anode = 100V, set R_cathode = 2 kΩ (1K+1K)
expect V_cathode = 1V

Repeat for second system.

>>1228942
What are you trying to say, exactly? Data sheets for every tube I own are available here: tubedata.milbert.com

>>1228942
also, I do not have a method of setting resistance

>>1228950
This would be my simple and robust recipe to validate the results of the tester by means of the data sheet and a multimeter. There are two (red) pairs of values in the diagram. As long as such pairs correspond to the diagram, the tube is ok.

>>1228957
Thank you, I will test it soon

>>1228964
What makes it so robust is that you do not need to exactly set the anode voltage nor the (grounded) grid voltage. All you need is a resistor between cathode and ground. All else is done by the tube itself. The test is whether the pair of values corresponds to the characteristic in the diagram. If it does, the tube is ok. You only have to measure the anode voltage and the voltage across the cathode resistor which is a measure of the anode=cathode current and at the same time, the (negative) grid voltage. Good night from the 'timezone'.

>>1228925
Yeah, I'm sure I'm inserting it the right way. It's like the SD locking mechanism is jammed.

>>1226935
Look up PAM8403 amplifiers. Buy one. Solder ins and outs. Done.

>>1228836
>building a toaster from scratch
I see what you mean. While I do like the idea of building a wire-mill, and maybe constructing passives from scratch, I am a strong believer in economies of scale. The only reason I'd build primitive radio tech is for the learning process, because I find hands-on learning to work for things I can't understand. Metallurgy, chemistry, and basic physics principles are rooted enough in my mind from school that I don't feel the need to start a smeltery for the sole purpose of education, though I'll admit home-smeltery goods are probably more marketable than home-electronics.

Has anyone here tried producing many of a small electronics product, like a breakout board or other small circuit, and sold them? While you can do the maths all you want, I worry that the labour (and associated injuries) involved would end up driving the price into obscurity. The only purpose I can see for this sort of product is selling something that has a particularly small market, such as audio transmitters for a small country which allows for higher signal strength (NZ allows for 0.1W from 502MHz to 510MHz), or niche guitar pedals, or maybe something for other hobbyists.

>>1228997
So I fucked with the little hook mechanism in the back of the microSD card slot, and amazingly the card it clicks in now. Unfortunately the hunk of shit now refuses to write to the card.

>>1229114
>a particularly small market
Right, boutique guitar amps are the most common place I know to see hand-construction, not only because using WLCSP packages spoils the whole aesthetic. These are devices their owners look at and put their hands on daily.
Even still, you might be surprised how little it costs to have some factory in China robotically assemble even 100 units for you. No god-tier tweezering and toaster ovening can beat it unless your time literally has no value.

>>1229130
If it's not a matter of formatting the card with FAT, it sounds like you might have fucked with just a little too much, m8. Time to get out your dental picks and have a frustrating night unfucking the slot.

>>1229131
>boutique
I was thinking more along the lines of "obscure to ludicrous", like turning the sound into a combination of square waves, or feeding high voltage back into the pickups to make your hands move a little differently with the resulting shocks. I think there's a reason I haven't made my musical debut...

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Any tool and die makers here im trying to get into the business and would like advice for starting

>>1229131
>Unfuck the slot with toothpicks

What

>>1229180
Dental picks. They are handy hooks to have around for various things and plenty tough for any job.

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>>1226768
Ok guys, I finished my custom coffie machine control board. Works pretty neat, but there is a problem with steam getting inside. I used hot glue to seal it, but apparently it wasn't enough.

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>>1229266
it's kinda messy, but hey it works!

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>>1229269
Congrats! Awesome coffie machine. It really has a clock?

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>>1229304
not sure if your making fun of me, but yeah from atmega 8 with 32.768 crystal as external interrupt source. I can set it to start on specific time.

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>>1229315
Amazing. I never had one, I do it by hand (espresso). Yeah, I discovered the clock crystal with its two 22p(?) NP0 load capacitors. Good work, really.

>>1229321
Yup, that's 22p.

>>1227625
>>1227629
why can't you? skill, cost?

>stove burner stops working months ago
>now another burner won't turn off at all and is stuck on max
I had to unplug the stove. If it's the switches, can they be trivially fixed, or do they have to be replaced? It's an electronic stove, no physical buttons

>>1229336
show us some boards.

>>1229336
Probably a stuck relay. Cheap/easy to replace.

>>1229336
First whack the relay to unstuck it. If no success, test coil voltage. If active the problem is elsewhere.

Any guys good with microcontrollers.
Im trying to move away from arduinos and instead just use the microcontroller itself.
If I have a microcontroller, in this case an atmega8, and I want it to communicate with a pc program, how would I go about that. I have a usb asp or some avr programmer, but I dont think thats what Im looking for. Ive read about serial to com ports but Im not sure how its related. Most google results talk about programming the microprocessor.

>>1229385
You can use an USB-TTL adapter and then just communicate through UART.

You could also try V-USB to communicate with your pc without an additional adapter.

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Where is the grid of a vacuum tube grounded? I need to make sure the grid voltage sent through my tester is correct.

>>1229385
The simplest way is to use some UART to USB converter chip like FT232R (there are several others), connect it the microcontroller's UART pins and then code the microcontroller to send/receive shit via UART and write the PC software to communicate over a serial (COM) port.
I'm sure Arduino tutorials cover the software side.

>>1229393
Huh? Do you mean which pin is the grid? Check the tube datasheet.

>>1229397
For example, in a 6V6, the grid voltage is supposed to be -12.5. -12.5 with respect to what? Where can I stick my multimeter probes and read -12.5 in a powered tube?

>>1229398
All the voltages are referenced to the cathode.

>>1229266
>>1229269
i always wonder how these things can be modified.

>>1229401
thanks, I still know next to nothing about electronics if that wasn't obvious

>>1229315
>32.768k interrupts
You know there's timer/counter hardware in those things, right?

>>1229385
You'd most likely need to replicate the Arduino USB-to-serial interface, without the bootloader. The $1 USB-to-serial adapters you can find on aliexpress will be fine to start.
Without a proper native USB device interface (as in the ATMEGA/U or AT90USB parts) speaking USB is hard and limited. With a proper interface, you can do a lot of cool stuff and there are frameworks that make the USB part easy-peasy so that you can concentrate on the hard stuff.

vacuum tube tester guy again, when I set grid voltage to 0 the grid/cathode voltage reads 96.5 on my multimeter, -10 reads 98, and -50 reads 102. This obviously seems wrong. Am I misunderstanding something or should I get the tester replaced?

>>1229403
I guess it's worth saying that this -12.5V is just the recommended/typical bias for amplifiers and that you're unlikely to see it in your tester.
Like the other anon said, you should compare the grid bias to the plate current.

Sup /diy/kes.

What is my best bet for plugging a speaker directly into a wall without an amplifier and without frying the speaker?

Put a fucking giant capacitor in front of it? Or run a bunch in series to get the resistance up?

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>>1229385
there are two most popular options:
1. those 1$ usb to serial dongles from ebay connected directly to USART bytes. You can find them as "USB to ttl"
2. Just do the same as arduino authors and use ft232 chip. Pic related

Speaking of pc software, RealTerm works pretty good, but it can be pain to install in never Windows editions that because of not signed drivers.

>>1229407
Nevermind, I'm way out of my league. The seller has been extremely nice and I'm probably just a retard

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>>1229402
it's pretty simple device- there are two boards, one with power supply and realy and another with microprocessor to control it. You don't need to worry about setting temperature because there is a thermocouple on heater cord. I just set PB5 to switch it on.

>>1229406
internal oscillator of atmega8 is inaccurate as hell. It gave me 50 minute error after only two days of work in my first alarm clock.

>>1229423
pretty much all internal oscillators ever.
datasheet should give you a good idea of the drift possibilities, temperature is a big factor

>there is a thermocouple on heater cord

you mean a thermostat on the heater, shirley.

What's a recommended general purpose N-type MOSFET? Something cheap for switching 5-12V with minimal losses.

I have a server I'm running and I need to move it to the other side of a room without losing power. Can I just make a male-male extension cord, plugging one end into the computer power strip, then the other end in the other wall?

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>>1229343
Not much to show. No physical damage apparent, although the board which holds the relays has abysmal traces (looks like they're bulging/flaking in places, but they feel solid).
>>1229345
>>1229351
Here are the relays. They all click, even when the broken burners are activated or turned off. Would a stuck relay still click? The black one is a relay, too, I think, but the orange relays correspond to the number of burners. Unfortunately, not cheap nor easy to replace since I would have to learn to solder in the process, and buy tools, etc.

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>>1229423
That wasn't what I meant. Pic related

>>1229459
>general purpose
I like IRLD024. 60V, 2.5A, Rds(on)=140mohm at 4V Vgs, in a comfy little PDIP-4 package. IRF520N is the favorite for larger currents and voltages.

>>1229463
You can but you'd better make sure the outlets are wired to the same legs of the mains supply and that there is zero voltage difference between the hots of each circuit and the neutrals of each circuit. Also, the newer generation of breakers might trip on unequal current flows.

>>1229468
>looks like they're bulging/flaking in places, but they feel solid
Would have to see pics.
>Would a stuck relay still click
Could, if the contacts have come loose from the armature and arc-welded closed or vaporized open.
Self-repair will probably be cheaper than a replacement board, even if you have to pick up a cheap fire-starter pencil iron and a pocket pack of solder.

>>1229412
What are you trying to achieve?

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>>1229474
>Would have to see pics
Couldn't get it without flash due to poor lighting, but you can see the top of the board near the corners. The thick leads look off

>>1229474
actually, I use Timer 2 in async mode with 1024 prescaler mode, not external interrupts in my clock. It gives me overflow interrupt every second.

>>1229489
As I thought, just adding solder to increase current capacity of the traces.
You'd have to check them with a continuity tester to be sure it's the relay. The good news is that, if it is, those can be changed fairly easily. You'd need a pencil iron, some solder, and a solder sucker, in addition to the replacement relays.
It looks like an uncommon part. Here are some vendors for you, it looks like $6 each on average depending on where you live. https://octopart.com/search?q=RTH34012

>>1229497
You're a pro.

>>1229489
The blobby stripes are normal, that's fine.

The joints to the relay contacts do look like potential issues. If you've got a multimeter check for resistance.

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>>1229503
>>1229504
Great, thanks for the help. I will get my hands on a multimeter and and figure out how to test the relays/contacts, then possibly work from there.
One last question though: can anyone identify what pic related is exactly? It's a terminal at each burner itself, and I'm wondering if it can be another potential point of failure given that it's right near the burners and maybe high temperatures.

>>1229530
That's the thermostat. Could be a point of failure.

>>1229530
>IRLD024
It's probably ceramic or a high temperature thermoset plastic, but the missing connector on the bottom-left does bother me. Is there a loose lead anywhere that could connect to it? Alternatively, does it look like there's a faulty or unintended connection between that left terminal and the metal beneath it? It doesn't look too normal to me. If the others are all the same then it should be normal, but check to see if there are any inconsistencies within the device itself.

>>1229542
>>1229544
>thermostat
>IRLD024
One and the same, or the thermostat contains a MOSFET? It's very large, while "IRLD024" looks tiny. But don't bother explaining, this is all over my head and level of education.
>missing connector on the bottom-left
>It doesn't look too normal to me
It's hard to tell from the picture, but it's actually welded directly to the prong. And yes, all are the same.

>>1229563
Different threads of conversation. IRLD024 related stuff was for the anon asking for all-around handy MOSFETs.

>>1229565
Oh, thank God. Looking at the spec sheet made me really confused in trying to figure out how that thing could handle the draw of the burner.

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>>1229544
>the missing connector on the bottom-left does bother me

>>1229576
Spot-welded?

>>1229563
>>1229565
>>1229569
Yeah shit, it was still highlighted when I made that comment.

>>1229583
That might make sense, and it could also be a failure mode if badly done. Though those spot-welded battery tabs and pot handles seem pretty resilient, so it should be fine. If the thermostat is broken such that the element always thinks its over maximum temperature then I can see why it wouldn't work. The thermostat could also probably break so the other element is always on max power, but we'd have to see how the temperature control works.

I'm not sure how it's usually done, but I can't imagine it being either relay PWM or multi-taps in the element, so I guess it must be the thermostat cutting the power to the element when it gets up to temperature. Meaning the thermostat is likely a temperature dependant resistor of some sort, and the voltage between it and a fixed resistor would be compared to a voltage divider that reflects the desired temperature as set by the knob. But that doesn't really explain why most elements have incremental knobs, not continually variable ones. I also don't recall my elements making relay clicking noises when they're on, and the elements take longer to get up to temperature when on low than high, but my elements might be multi-tapped, I don't know.

Since your PCB has 6 relays on it there can't be one for each power setting, and the many paired resistors do resemble voltage dividers for the selection of power settings, but on closer inspection they're all in parallel. Judging by all the extra jumper leads there's another control board, which might contain the comparators, though it would be a bit strange, especially since I'd think even the thermostats would be isolated from the control board for being so close to the elements. The traces from the relay-powering transistors go straight to the control board, so could we get a picture of that too?

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>>1226752
What do you mean?

>>1229611
We need a wiki if only to store these images. I wonder if bunkerbro would be anxious of a public website with all his recorded posts? It would make it pretty easy to dox him is someone wanted, provided there's enough info. Otherwise I guess it would be kind of a hive for relevant infographics and links, like /k/'s murdercube, except called "shotofblack.com" or something. Thoughts?

>>1229480
At a guess, edge.

>>1229618
I am fascinated. Not enough to go register shotofblackbooru, but fascinated.

>>1229618
>>1229620
Dynadot is having a sale on .top domains, so it could be pretty cheap to get started. I've no time though.

>>1229620
>>1229621
Maybe we have some guy who cross-boards with /g/ who'd be willing to make one? At the least this deserves a meta-thread, provided there isn't one at the moment. The wiki would also be a good place to keep generals' pastebins.

The one problem I have with the idea is that /diy/ is one of the slowest boards.

>>1226748
/ohm/, i want to splice power supplies in parallel to get more power

i did this once for a 'gaming' laptop, but it didn't work
the laptop needed a 60w psu, so i spliced two of the same 30w psu together, but the bios didn't detect the increased wattage
im guessing that the separate wattages were overrated anyway
i also noticed that the current seemed to feed into one of the psu, so maybe i needed to add diodes?


i want to try this again, but for a different circuit (not a consumer electronic device)
should i add diodes this time? and how should i arrange them?
the psus i want to try and parallel together will be over 100w each

>>1229634
>didn't detect the increased wattage
I'll assume that makes sense. Now if you're really serious about this you'll take apart both power supplies and make them share the control parts so that they don't interfere with one another. If they're simple enough to provide a circuit diagram of (and you're willing to solder some stuff and maybe bodge a few boards together) then it's quite possible, maybe with an extra part or two. But if you're really really serious, you'd just buy the right power supply because it would be cheaper than two half-power ones. I'm actually surprised nothing bad happened to the computer or power supplies the first time, I thought a ground loop would have caused something to heat up. Just in case, make sure that both power supplies still work before proceeding.

So to what degree are you prepared to modify the power supplies themselves?

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>>1229638
>So to what degree are you prepared to modify the power supplies themselves?
i don't want to spend too much time on this, really.

this would be for a project i might revisit down the line for a 'dumb circuit' that could use more power (not computers this time, but for a sort of analog oscillating current thing)


>pic related
are the type of power supplies i want to use, already got one

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>>1229609
>If the thermostat is broken such that the element always thinks its over maximum temperature
The LCD for each burner displays "HS" for "hot surface" when the element is hot. The dead burner does not display this, so it's seemingly functioning correctly in that regard. The stuck burner displays "HS" constantly, so the thermostat is functioning correctly there too. So it seems the thermostat temperature-function is working but maybe not the current switching or whatever if this is indeed controlled by it?
I unplugged the connectors for the stuck element, but the controls don't detect this and allow you turn on the nonexistent burner, and the relay still clicks when you do so despite no current draw. Of course now it doesn't display "HS" since the thermostat is disconnected.
>Since your PCB has 6 relays on it there can't be one for each power setting
Well, besides the one little black one, the 5 orange ones each correspond to one of each 5 burners, I think. I'm only guessing here, but by listening to the relays (they click on and off during burner operation), they appear to cycle on-off periodically. Basically, the lower the burner temperature setting, the more clicking you hear periodically (or, more correctly, the shorter the "ON" interval is), while max temperature setting there is no clicking. So I guess what you're getting at is whether or not this is controlled by the thermostat?
>could we get a picture of that
This is all I can get since the remaining burners are currently predisposed.

>>1229266
>>1229269
>>1229304
>>1229315

Noice. For the moisture intrusion I would seal it with either caulk or go to the extreme and pot it with epoxy resin.

>>1229480

Realizing the sinosudinal form of an outlet as sound

And edge. Who cares? It's cool

>>1229688
edgy, eh? you'd need a step-down transformer. down to a normal voltage that speakers operate at. and some way to control power to the speaker, like a rheostat that can dump the excess wattage. also, your transformer should be an isolation transformer. don't forget to ask your mom.

>>1229650

when paralleling supplies you always put a diode in series with each positive lead.

if the supplies are dumb, this will always work, as the lower-voltage one will kick in as the higher voltage one falters. if the supplies are intelligent, then it's possible the one with the higher voltage (no 2 supplies are equal) will shut down when too much current is asked of it, and the lower-voltage one is then on its own, and shuts down too.

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>>1229690

no, nigga, in the same way you can power LEDs directly from 120Vac using a cap to limit current, you could do the same with a speaker.
(or a prostate massager, which is what the dude is probably trying to make)

>>1229696
what part of sinusoidal do you not understand?

>>1229699

you're seeing only the details instead of grasping the concept. this is typical of people on the autism spectrum, so i'm not blaming you, only your genes.

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>>1229696
>using a cap to limit current
>>1229699
>what part of using a cap to limit current do you not understand?

>need a 50cent part from Mouser that I can't find locally
>20€ shipping

>>1229714
>>20€ shipping

Sounds like you could make a fortune by starting a shipping company that will ship small items around the world for low cost.

What astounds me are the Ebay deals where you get a decent part for a low price, the shipping is free, and it arrives 3 days later. How exactly is this possible? Even if the part were garbage it's still amazing that they make a profit.

I need a new budget multimeter. Is there anything worth chinking under 10$?

>>1229720
Richmeters rm101 or holdpeak hp-37c.

>>1229719
Chineese government is subsidizing shipping cost.

Hopefully the microcontroller guys are on right now. I want to use a PIC to control RGB LEDs that use the WS2812B chip. There's code for it available here:
http://stevephillips.me/blog/using-ws2812b-pic-microcontroller

I want to test it out before I start modifying it and integrating it into my code. The one part of the code that I don't get is in this loop in main:

while(1) {
CLRWDT();
// timing on the WS2812B is very precise. turn off interrupts before talking
GIE = 0; while (GIE);
ws2812_send(&led);
GIE = 1; while (!GIE);
}

Particularly, the GIE stuff. It looks like that loop won't do anything, since the conditions of the while loops are set false in the line right before each.

Am I supposed to interrupt it by switching a high signal on the interrupt pin or something? He didn't configure it as an input so I doubt that's the case.

pls help

>>1229741
>the conditions of the while loops are set false in the line right before each.

he clears GIE to 0 to disable interrupts but then to be safe he waits until GIE has been cleared. then he does the led work.

then he sets GIE to 1 and waits for it to be set before looping. I'm not a pic expert but I don't see what this accomplishes unless it's to make sure that GIE is set for long enough to process any pending interrupts.

>>1227932
I ended up finding something useful, a capacitor with you guessed it, 15V. I'll be drawing 30mA, is that too much? and do I go in parallel with the capacitor? the capacitor is filtering some diodes off of the transformer.

>>1229750
Ah, gotcha. I thought while; would loop the next line, not loop nothing.

I bet if there's an interrupt flag set, enabling GIE lets the flag then act as an interrupt.

if it's true that I can manually rotate the shaft of a DC motor to turn it into a DC generator, can I manually rotate the shaft of a diesel engine to make diesel?

>>1229741
Guy is obviously a knobber.
Hates bit banging and timings? Welcome to embedded lol, if you don't like it go write some apps. Microchip community isn't as good as arduino community? You mean they aren't interested in spoon feeding you warm diarrhoea?

Anyway, clearing the watchdog timer isn't necessary, just turn it off.
Interrupts aren't being used in the code, just don't touch them they are disabled on reset.
Even if it is a snippet of something bigger the loops do absolutely fuck all, if you set or clear the bit then its set out it's clear, there isn't a delay, the pic isn't busy or distracted, you set it it's set.
Semicolon on the loop implies curly braces and therefore the loop.

>>1229793
You don't need to bet, you just need to read the datasheet.
There is a global interrupt enable, enables for some peripherals and sometimes depending on the device there might be one in between and enables for high/low level interrupts.
Setting all the enable bits required for an interrupt allows the flag bit to cause the device to call the interrupt routine, I think it just unsets gie, pushes the current PC to a stack then loads the interrupt address.
RETFIE does a return as well as setting the interrupt enable bit.

>>1229818
To be fair WS2812Bs are pretty annoying.
Especially since the data sheet is pretty crappy and has some things plain wrong.

>>1229826
>To be fair WS2812Bs are pretty annoying.

what exactly do they do? I looked at the pdf and saw that you can daisy chain them, and they have serial data, RGB, and something about 10 LEDs. Are they just adafruit tier led shows or what? Does each unit make 10 different lights/colors at a time, or do all 10 just combine to make one light?

>>1229829
Yeah they're the "LED"s behind all of Adafruit's pixel stuff.
They're RGB LEDs with controller all together in a standard 5050 package. You can chain them (much more than 10 IIRC) and set every color individually through the serial protocol.

>>1229738
>Chineese government is subsidizing shipping cost.
USPS also subsidizes them in the form of greatly reduced rates.
Once the package enters the USPS system it's handled as First Class mail with tracking information included.

>>1227941
Currently working for a company that makes bike lights for rental bikes like the ones in London and they shine a green laser light onto the road in front of you.

Think it's a waste of time desu

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>>1229903
>USPS also subsidizes them in the form of greatly reduced rates.
>Once the package enters the USPS system it's handled as First Class mail with tracking information included.

so take advantage as long as it lasts. the USPS has been a joke for decades; they deserve payback.

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>>1229916
Green Laser - Silly bike symbol - Only £125 - Shop Now!

Is it that?

>>1229916
fuck sake.
you know why drivers hate cyclists so much?
its things like this. stupid distracting shit.
its a bike not a fucking disco

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>>1226748
What would the best place be to put a diode if I were to change the lamps to LEDs in this schematic? I'm thinking of doing it where I put the red diode symbol, but I'm not sure if that would work.

>>1229977
LEDs are already diodes.
need to see the rest of it but probably just forget the diode.
add a resistor instead for each led added.
presuming a voltage source for a 2v, 20mA led you need ~300 ohm resistor to drop from 8v. 330 is closest in E12, you could try a 270.
If its constant current driven you would need to use 40 LEDs in parallel.

all of that maths might be wrong because the diode will have a voltage drop that won't exist if you remove it. so account for that.

>>1229977
(assuming this is some kinda audio gadget running AC and not a car running DC) you can put the diode in either line. the only consideration is the LEDs point in the same direction as the diode, electrically speaking. also, dont forget a current-limiting resistor in series with each LED.

>>1229979
>LEDs are already diodes.

which have a very low reverse-voltage breakdown. you need a proper diode to save the LEDs from death.

>>1229832
>much more than 10
I've got a string of 240. As far as I can tell the only limit to how many you can daisychain is power and the amount of time it takes to set each one, since you have to program 24 bytes for each chip before the one you want to change.

>>1229989
bits*, not bytes

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>>1229979
The lights are currently fed with ~7.4 volts AC (~7.8 when I measure with my multimeter).

>>1229983
>save the LEDs from death.
they will pass the same current in reverse, heat isn't going to kill them.
put one in backwards if you are worried.
>>1229991

>>1229652
That sounds like what I thought what was going on, the thermostat is almost certainly switching the element relays off when it detects they're up to temperature, though this might not necessarily correspond to the HS indicator, which in my experience will remain lit as the element cools down after use. But that depends on whether it's really a "hot surface" indicator or "up to temperature" indicator.

In that case, do the dead and permanent-on burner relays click at all? if not, the problem is the relay or the transistor powering it. If these relays do click, then the problem is the element itself. This second explanation makes sense for the dead burner, but not for the permanent-on burner; its problem has to be in the control circuitry somewhere. Hopefully it's just the relay or transistor, but if those aren't being activated in the first place, then you'll have to trace the traces back until you find what's gone wrong. To test them you'll need to put your multimeter's ground lead (preferably with an alligator clip on it) on the low-voltage circuit's ground (maybe the - symbol on the top of the header on the right of >>1229489) and probe around with a point on voltage mode looking for highs and lows. If the base of the transistor of a broken element (all of those 3 terminal SMD packages pointing into the array of resistors that power the relay coils) is powered periodically (compare them to the other terminals, one should increase in voltage when its relay turns on) then the control circuit behind it is functioning. Then check the voltage after the transistor, and if that turns on then the transistor is functioning, and not the relay. 'Course that does mean probing about on a live board, but it's probably the only way of going about it, save listening to the oven to hear the relays, which doesn't completely diagnose the problem. Just FYI, the sections of the board that are surrounded by those criss-cross lines are high voltage, but the middle are 5-12V.

>>1229712

Sup my nibba. So it can be done?

>>1229994
>they will pass the same current in reverse
Are you stupid? Their reverse current is usually on the order of µA, and if you surpass their breakdown voltage it's not a good idea to assume that they won't break. There's a bit of debate on this, but if you're putting mains voltage across them, even with a current limiting resistor, I wouldn't trust them. An LED's breakdown voltage is typically greater than their forward voltage, so if you have a proper current-limited voltage supply (or just a dumb voltage supply) that will never supply the LEDs with more than a little over their forward voltage, you'll never surpass their breakdown voltage. But if you're powering the LEDs through a current limiting resistor, then on the reverse cycle the LEDs will let very little current flow through them, meaning the same very little current will flow though the resistor, which will consequently have a very low voltage drop across it. Since almost all the voltage will be dropped across the LED instead, it will probably surpass its breakdown voltage and take a shit, because LEDs are simply not manufactured to conduct in the reverse direction like a Zener is. A mains rectifying diode costs shit-all, so go with that if you're using dropper resistors.

>>1229997
You could just do it with a resistor if you wanted, but it depends on the power and voltage (or impedance or current or inductance, any 2 of those stats is enough to paint the picture) the speaker is meant to function at. Just figure out what voltage you want dropped across the speaker to give the correct volume (play it a little safe), then treat it as an impedance operator in a voltage divider. I think it's a good idea to treat it as an inductor, so the current through it will be 90° out of phase with the voltage across it, meaning you'll need to work out the voltage divider with phasors/triangles. If you have the specs on hand then I could give it a go.

>>1229997
It can, but it will not sound as you may expect. The technical reason is that the current limiting capacitor and the load form a high pass filter. Every switch, fridge, power tool or dimmer will become audible - an extreme form of minimal techno. Enjoy the mains stream muzak..

>>1229998
no need to be rude.
>surpass its breakdown voltage and take a shit
try it, surprise yourself.
the lamps are rated 8v, source voltage is ~7vac
the same resistor that protects it normally will protect it in breakdown from power and overheating.

>>1230001
>source voltage is ~7vac
Assuming that's 7Vpeak, then wouldn't that be the situation where the voltage source is below the breakdown voltage of the LED in the first place? Anyway, I know the resistor will limit the current past breakdown, but I was under the impression that it wasn't the power dissipation that destroyed the LED in breakdown, but rather that it enters breakdown in the first place. I'm no expert on failure modes, but I still wouldn't trust it to survive that over multiple years if it survived even for an minute.

>>1230002
Breakdown just means it allows current to pass, unless its kV that rips new paths in the substrait it shouldn't do anything irriversible. Zeners operate in breakdown region all the time, the only difference is the voltage they are made to breakdown at, not the ability to do it at all. There is plenty of anecdotal evidence of leds bring run in breakdown region with bi apparent I'll effects, the only opposition seems to be people pointing at data sheets as if they are ever the gospel! Why not try it and let us know.
Or just keep the diode in, what is it like a few pennies?

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>>1229991

>>1230024
>solid black bar equals transformer secondary or AC voltage source
>diodes with lines through them and only 1 arrow
What horseshit schematic software is this?

>>1230056

shut up, dude, it's a beautiful mother schematic. follows all the proper conventions. everything's clear and obvious, everything's labeled. compare that with the Eagle atrocities we see here everyday, and thank Allah for your good luck.

>>1229999
>mains stream
I'm gonna have to go ahead and check those quads.

>>1230011
Different materials. I mean, since aluminum electrolytics can take a bit of reverse voltage on a regular basis why not do the same for tantalum amirite?

>>1230056
lern2europe
lern2 >>>/g/

>>1227824
Literally any of them. Same chip

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>>1230056
>What horseshit..
My own InkSim.

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>>1230106
That's only one of the IEC symbols for a transformer coil, not an inductor, and even then it's hardly common. The standard IEC inductor and transformer coil are just a series of connected semicircles.

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Shit I just made this low-pass filter for my earphones and boy does it cut out that treble. It makes it sound like I'm listening to the music being played from the floor above me. It's pretty stupid, but fun for a change. Any more advanced analogue EQs I can make?

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>>1230125
Functional abstraction supersedes naïve naturalism, one funeral at a time.

>>1230151
I fucking hate it, it looks like CAD said "there's 400 turns in this area, each line is 4 typography points thick, so I'll draw them all in even though the result is just a black bar". I swear it's a conspiracy by printer companies to make us use more toner, or by pencil lead companies. I can see how when drawing a transformer with more than 2 coils it means you get an even space on either side of the wires so the centre ferrite is evenly spaced between the wires, but surely there was a better way of doing that than a black blob. What's next, the capacitor being replaced with a black circle?

So out of those first two, which do people here prefer?

>>1230151
IEC disagrees with you. The black block isn't in use anymore.

>>1230168
>ink manufacturers on suicide watch
Antifa disagrees with you.

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>>1230140
>just getting to sleep listening to calming bass
>wire on shitty gadget breaks
>pic related
>lights on
>fire up the soldering iron

making a monitor out of a broken laptop lcd

first real /g/ish project besides putting together computer hardware

i've learnt so much, so comfy

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>>1230235
>i've learnt so much

what have you learned really?
- typing your credit card number into amazon/ebay
- inserting some male connectors into females

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>>1230253

well you might as well forget about getting hired at adafruit with that elitist atitude

>>1226748
Why are there so few proper resources on synth DIY? Not just schematics, but why it works and how.

>>1230266
>why it works and how.

you should be able to find tons of info on both analog and digital synthesizers.

the sound track for clockwork orange is incredible considering what Walter Carlos had to work with. no wait a minute, he's Wendy now. anyway, her work was awesome.

best book to learn circuit analysis? Nodal, mesh and the whole bag

>>1230341
in my college classes we used this one: https://www.amazon.com/Fundamentals-Electric-Circuits-Charles-Alexander/dp/1259071391/ref=sr_1_6/143-7972013-8658456?s=books&ie=UTF8&qid=1503167307&sr=1-6&refinements=p_27%3AMatthew+N.O.+Sadiku
Thought it was clear enough most of the time. The only chapters I thought weren't explained very well at all were the later ones about Laplace and Fourier.
That said the topics are not particularly difficult, especially DC/single phase AC, so you could probably use any ole book or even internet tutorials.

>>1230353

apparently you can download a PDF of that from here, as it's open source.
(last time i downloaded an open-source technical book, it was such pure crap that no self-respecting publisher would touch it)

https://archive.org/details/FundamentalsOfElectricCircuits5thEdgnv64_201406

>>1229627
I have a server, couple of VPSes and a short (9 characters including the dot and TLD) domain as well as the required experience. I'll try to set it up, so stay tuned.

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>>1230357
>>1230353
Thanks anon, I got it.
I usually frown on asking 4chins to help me with studying but /diy/ is a nice board. The test asks for a r1 values that makes i0=0. I'm clueless because it's shorted.

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>>1230357

fuck, just got to page 7 and this silliness shows up. it would seem...
- a battery is not DC coz its voltage, and thus current, varies with time.
- a triangular waveform is not AC coz it's not sinusoidal

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Nooby noob here trying to modify an oscillator (see pic). On circuit js there is an example under Circuits -> Transistors -> Oscillators -> Emitter-Coupled LC Oscillator where this screenshot is based on. While it's easy to adjust the frequency by modifying the capacitor I can't seem to be able to adjust the output voltage to the 3 V that I would ideally like to get. Any help is appreciated.

>>1230369
Not possible. This type of oscillator stabilises itself at about 1Vpp. You would need a single stage post-amplifier. I don't think that (as drawn) the circuit will oscillate anyway. What is 'circuit js'?

>>1230381

right thanks.

circuit js is a online circuit designing tool. just search for it online or use:
lushprojects com circuitjs circuitjs html (replace spaces with dot, slash, slash, dot)

>>1229627
>>1230363
>>1229618
>>1229620
>>1229621
>>1229627
It's finished, you can find it at wiki.printf.pl

Where can I find spare beefy stepper motors?

>>1230444
Neat.

>>1230140
how does it work?

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This is a stupid question but I'd just like to be absolutely sure: it won't cause any problems if I trim the wires on this to remove the JST connector, right?

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>>1230575
The first 1mH inductor in series acts as a current limiter to higher frequencies, since its impedance is proportional to frequency. The capacitor in parallel with the load inductor shunts high frequencies to ground, while blocking more of the lower frequencies and forcing them to go through the load since its impedance is proportional to 1/frequency. This combination acts like a very extreme low-pass filter, causing more resistance to higher frequencies. Since it doesn't actually amplify the lower frequencies, I have to turn the volume up to get the same juice out of it.

Pic related shows the input voltage and the current though the inductor, with three frequencies though it.