/diy/ - Do It Yourself

requesting info/resources on the basics of inverter design

>>1847774
>tfw the wall cube regulations keep getting stricter and stricter
>tfw no full auto short-barrel-connecter wall cube with a capacitor-whine-silencer

>>1847776
Nothing more than a glorified boost converter that runs pwm through filters to obtain a cleaner sine wave than with modified sine which is usually a bullshit convoluted square wave. Study boost converters, look up high voltage switching techniques and look up datasheets from ics made for the purpose and go from there but it is a steep learning curve. Hope you're proficient in math. What do you intend on powering?
>>1847774
Where the hell is diodegonewild, shango066 and radiotvphononut? Shango is fantastic for people wanting to learn how to fix old junk and he's funny to boot.

>>1847829
I've aced up to ODEs so hopefully math won't be too much of an issue
I just want to learn about them for shits and giggles. I'm building a solar panel MPPT tracker and now I want to come full circle and learn about inverters, even if I don't want up making one myself.

I understand "feedback" in the very narrow sense for op-amps, and I understand "feedback" in the very broad sense that it's feeding some of the output of a circuit back into the input as a form of regulation

what I don't understand is recognizing when a circuit of mine would benefit from feedback. That, where I would apply the feedback, at what stage of the circuit, from what output, etc.
any guidance?

>>1847900
>when a circuit of mine would benefit from feedback
this is easy. circuits that can be represented mathematically can be observed to have varying outputs given variation in parameters. if expected variance in design parameters causes a change in the output that's larger than you can tolerate, you need to add feedback. two examples: boost converters have an output voltage that depends on the load. low loads can result in a dramatically increased output voltage, so if that combination of parameters is possible then you need to add feedback. buck converters have an output that depends a little bit on the load but not too much. if you can tolerate that variance then you don't necessarily need feedback. however their output varies linearly with their input. if you have a widely varying input voltage then you need feedback.

>where I would apply the feedback
this can be hard but fortunately most circuit topologies already exist so you can just read about them. obviously though feedback goes from one of the outputs to one of the inputs. this can either be small signal feedback like in the case of a switcher ic, or the feedback can be part of the power path (like a fluorescent ballast i guess).

>from what output
this depends again on 1) what outputs you care about, 2) what parameters you expect to vary causing an inconsistent output, and sometimes 3) what feedback scheme gives you the fastest/most stable response. item 3 is important and can prompt you to do weird things like adding feedback to outputs you don't necessarily care about, like in the case of switch current feedback in many boost/flyback converters. this stuff is complicated, there's no easy answer other than learning from existing topologies.

Complete noob here. So excuse the question, but how does one use a MOSFET as a sort of relay? i.e. to drive, say, a spark plug coil?

I'd like to use a solid state driver connected to a micro controller to make sparks at different intervals depending on input.

5 minutes in paint to make a diagram is all i ask. I'm a visual learner.

>>1847926

does anyone have a recommendation for an introductory control systems/control theory book?

>>1847932
Complete noob here, How do those symbols and pinouts translate into real life?

>>1847932
Ignition coils are autotransformers with three leads IIRC. If the spark is meant to be positive you may need to use a PFET, not sure.
Also you'd need that FET to be suited to high-voltages. An IRF840 should work, they're good to 500 or 600V, which should be at or better than a relay.
I also wouldn't use a resistor in series, and instead use the RL time-constant of the coil itself alongside the limited pulse-width for current limiting.

>>1848072
>How do those symbols and pinouts translate into real life
Look up the datasheet for the part you intend on using, different MOSFETs have different pinouts. For example: http://pdf.datasheetcatalog.com/datasheet/fairchild/IRF840.pdf
What do you intend to use to turn the MOSFET on and off? A button? Note that you probably won't want continuous DC going through the ignition coil, so I'd recommend having a pulse-shortening circuit between the button and the MOSFET (assuming you aren't using an arduino or whatever). A common monostable 555, while kinda shitty, may work for this. A common monostable comparator should also work just fine. But neither will be an ideal gate driver, you might want to use a BJT or two to drive the MOSFET's gate.

>>1848023
Do you know electronics and diff eq yet?

If a normal LC circuit will cause a sine wave when resonating, is it possible to add undertones and harmonics to this wave with other LC circuits connected to this? And make an oscillator that ends up sounding like a particular note of an electric guitar or violin? If so, I wonder how hard it would be to make that oscillator tunable, such that the harmonics also tune with the main oscillator? I'm trying sending an impulse to a capacitor in series with a bunch of different (integer multiple) inductors, each with a resistor in series, but I'm just getting a sinusoidal ringing. Well, even if it did work, I'd likely have no method of adjusting the phase of each harmonic.

If I use a summing amplifier I can definitely combine a bunch of different oscillators, but I wouldn't be able to tune them all at once if they were individual oscillators. On the other hand, I could use an array of PLLs, each with programmable dividers for setting harmonics, and sum them together like that. But I'd need a frequency independant continuously variable phase shift in there too for really matching the waveforms, which I'm unsure how to attempt. The only thing I can think of is a normal all-pass filter with a photoFET setting its corner frequency, and an extra phantom feedback circuit with an identical photoFET on an identical RC circuit, somehow.

But maybe there's room for adaptability with the PLL's phase comparator, or otherwise performing the sine-to-square transition before the phase comparator. If the amplitude of the VCO was constant, I'd be able to use a phase-fired control, just toggling when the voltage gets to a sufficient height. Even if it wasn't a constant amplitude, I'd be able to use an ideal rectifier to make my divider's reference voltage equal to the amplitude of the VCO's sine. With the right circuitry (comparators and logic gates) I'd be able to trigger a flip-flop on both the rising and falling edges of the sine.

Thoughts?
>inb4 DDS

could i make a dc current meter by breaking a ferrite toroid in half and gluing it back together with an analog hall sensor in the gap? the one i bought only goes up to 35a and id like at least 50a

>>1848225

yes. I used a core made from motor laminations to sense the starter current in my truck. You can adjust the air gap to handle pretty much any current.

>>1848141
I have a working knowledge of basic electronics and am coming along with intermediate electronics, and I've taken up to and including ODEs

I'm reading Ogata right now and It seems like it's just on the brink of my knowledge. I'm grasping it so far but I feel like once I breach the 3rd+ chapters it'll be over my head

>>1848271
god help me if it requires multivar/PDEs because I haven't taken calc III or any PDE course yet

>>1848146
>If a normal LC circuit will cause a sine wave when resonating, is it possible to add undertones and harmonics to this wave with other LC circuits connected to this?
that's the textbook definition of additive synthesis

>>1848146
>but I wouldn't be able to tune them all at once if they were individual oscillators
use reverse biased diodes as varicaps

>>1848225
>>1848241
couldn't you just use a 1mOhm shunt resistor?

>>1848371

sure. i have a crate full of 'em.

>>1848382
heh for 500amp, sure. but the other anon said 50A so he'd need 2.5 - 5W max.

>>1848382
also i'd guess you'd need a heat sink bigger than your truck for this baby

man, people have told me that control systems/control theory is intense but I didn't expect this textbook to draw on information from practically every chapter from calc I, II, III, linear algebra, and ODEs - within the first 2 chapters

>>1848396
It's only 250 watts, which is less than what a high end GPU dissipates.

Brainlet here
Can someone explain to me why this fan I pulled out of a power supply undervolts fine but just sits there clicking when using PWM at 12V, even at like 95% duty? I thought fans usually behaved the other way around. I've used this controller on case fans with no issue.

>>1848465
Forgot pic

>>1848467
>>1848465
what frequency is the PWM

>>1848468
Around 25kHz

>>1848371
id need an instrumentation amp for a shunt and a power supply that reaches in the right region, but a hall sensor is floating
i already bought an acs758alcb-100b (±100a), but because you have to solder it in place its less usable.

>>1848477
this looks like a cool little scope. i totally need something like that since i am couch bound most of the time and i need something small and couch friendly

>>1848595
It's like $30 on aliexpress, comes as a kit

>>1848595
This is the official kit that I bought
https://a.aliexpress.com/_BOAu6W
Other chinks have chink'ed these chinks though and there's a bunch of clones out there on Ali too for cheaper. Don't know what the quality of them is.

>>1848597
got mine for like 15eur fully build and custom Open-DSO-150 or other custom firmware is a must (decent controlls, serial datadumb and 3 additional digital channels )

>>1848597
>>1848599

it looks way better than the one i bought a few years ago and it cost like $80 or so but was total crap. and no colors. i think it was also a DSO. but it was long time ago so i imagine they have improved the design and prices have dropped since then.

> 200KHz
oh. the one i had was 1mhz. but i doesnt really matter for me since it is good for little audio projects and i have a real scope for other things.

can you overclock it to 100mhz?

look at this: https://www.youtube.com/watch?v=SIH48bIUU00
100mhz at $70?

>>1848608
and it comes with a comprehensive protection of the fuselage! holy shit i am buying

My old folks bought some property on a rural area to get away from bug people life and I want to build a electronics lab on their backyard shack.

What kind of grounding is enough for it ? Will just sticking a copper rod down be enough or do I need ground enhancing paste, conductive gel and all that other shit ?

I wont focus on high voltage stuff but I might fuck with it eventually.

>>1848647
if you stick a grounding rod in the ground your shit is guaranteed to get fucked by lightning

>>1848664
Seriously, even if there's absolutely no sticking end of the rod on the ground and the adjacent house has a lightning rod ?

How do you make a good grounding for your electronics shit ?

Noob here, out of the Design/verification tools list, which one is most suitable for beginners?

>>1848664

Better question, what is some cool as shit stuff you could do with a lightning rod other than kill yourself?

>>1848715
https://www.youtube.com/watch?v=mpgAVE4UwFw
https://www.youtube.com/watch?v=3vvvv5QVZoA

Retard who cant into electronics checking in. If you had a vacuum tube guitar amp with the two output tube fuses blown would you assume that the tubes are fucked?

>>1848467
You might try to smooth it out with an elecrtolytic cap across the fan.

After watching all of these videos of cheap scopes, how hard is it to build your own high quality scope? The design seems pretty simple: a fast micro or a FPGA and a few fast ADCs. And the rest is software. I'd buy fast, high quality parts as my main motivation would be not the cost saving but rather convenience and the ease of operation. I prefer knobs and dials to multi function menus. I would have a bunch of dedicated knobs just like on the old fashioned analog scopes except I'd build a fully digital scope. I know software better than hardware, so luckily the hardware design can be pretty simple and the rest can be done by endlessly tweaking the source code. Right?

>>1848766
I'd probably replace all the electrolytic and/or waxpaper capacitors and check the tube's bias first.

>>1848813
Maintaining signal integrity as you move up the frequency bands becomes increasingly hard, especially once you start to reach the hundreds of megahertz.
Also, your code needs to run quickly and efficiently. My 200MHz oscilloscope runs at 1 billion samples per second. That means you need to be able to keep up with a gigabyte of new data every second, process it, and then draw it to the screen.

>>1848603
Can this be done for a DSO138 too? It's kinda shitty, but I wouldn't be opposed to adding a rotary encoder or two somewhere.

>>1848834
Fair enough. As always, the first attempt should be something modest, say 100Khz or 1Mhz, That could be done with just a micro and a single ADC as a proof of concept. If even that proves to be too hard, then forget it. I understand the main challenge with faster speeds is I'd need a fast FPGA talking to a fast ADC or two and buffering data and a slower micro pulling data from FPGA. 200MHz? Nah forget it. But I'd be happy to be able to build a *true* 20Mhz scope. I haven;t checked but I am pretty sure there are a bunch of schematics/docs available so I wouldn;t have to reinvent the wheel.

so my friend was reviewing my MPP tracker circuit and told me I would have to use a mosfet driver because of the switching frequencies involved and the 5 volt logic level of the microcontroller I'm using being unable to drive the mosfets at said frequency

but other than that, we're both too inexperienced to know what to do after that.
Do all of these mosfets need to be driven by a mosfet driver? Or, do only the ones directly connected to the PWM output need to be driven by a driver?

I have a blue plastic cap that has this text:

2100
D63JO
1.02

What's the value of this cap?

I'm making a simple noise making box at the minute that'll use a 9V battery and have a built in 1W speaker.
It's basically a single VCO that I can select the waveform on and adjust frequency with a pot, a single LFO that I can use to sync or modulate my wave, a single low pass VCF that I can change the cutoff on and a little amplifier circuit for driving the speaker.

I was just fucking around with ideas for making a front panel and box and was wondering if there's a relatively cheap and and simple way to show a waveform on a small screen on the box?
Basically like an oscilloscope but that has it's x and y scale preset and just wire it into where the output of the VCF enters the amplifier.

Considering that the entire project otherwise is gonna cost max about €20, I'd want something cheap (I have an arduino and teensy already if there's something I can do round them)

>>1849405
2100 pF

>>1849072
Go for it anon!
At just 20MHz I don't think your choice of ADC will wind up being too expensive.
High speed ADCs can be crazy expensive.
You can also use multiple slower ADCs and then interleave their measurements, but you need to be careful not to introduce any phase noise.

>>1849440
At audio frequencies you could just have a microcontroller use it's ADC to sample the audio output and then draw the sampled waveform to the screen.
That's basically all those cheap DSO138 scopes do.

Are there any good books on analog/modular synth circuits and design?
It seems like most all of the information left on the web is spread out on dying hobbyist websites.

>>1849464
No, back to /prod/

>>1849464
All the design is covered in books about signal processing. Learn signal processing.

>>1849483
I have learned signal processing, but those books typically focus more on signal processing concepts and less on practical circuit implementation.

I want to learn more about the kinds of circuits actually seen in analog synths, from transistor ladder and diode ladder voltage controlled filters, to the more esoteric things like analog pitch shifters.

>>1849501
Then search for books on audio circuits or more generally analog circuits. There's some on libgen.

>>1849464
maybe some of these
also Synth Secrets Complete was a series of articles on some website but it is also available as a pdf file.

>>1847932
ah yes the classic magic box chip

I think I have the right idea for this AC to DC adapter. I just need the numbers now.
1. Fuse current-- the load (a small soldering iron) is rated 2 A but it might draw more or less than that. Maybe I'll hold off on the fuse until I get the circuit working and then probe to see how much the variation is. Is there a good way to predict?
2. Winding ratio-- with all the components between the transformer and the load, there's gonna be some potential drop. Instead of winding to exactly 120 sqrt 2 : 9, should I wind it as 120 sqrt 2 : 9.2 or something?
3. Filter capacitances-- no idea what to choose.

Also I know the current on the primary side won't be 2 A-- I just mean that depending on what the actual drawn current is, I'd need different fuse ratings

>>1849689
>Is there a good way to predict?
Datasheet
> all the components between the transformer and the load, there's gonna be some potential drop. Instead of winding to exactly 120 sqrt 2 : 9, should I wind it as 120 sqrt 2 : 9.2 or something?
Read the datasheets for the components, add overhead as required by your regulator. Your regulator.
> Filter capacitances-- no idea what to choose.
The ones that filter out the noise that your regulator and load shouldn't see. I wonder if there's some kind of sheet of data which would discuss these things.

>>1849691
Bro what. What data sheet would tell me the current draw range of a soldering iron? The thing barely has a manual. It gives one number for voltage and one number for power.
And there are ten thousand capacitor data sheets on a vendor's website. I don't know which capacitor to use. That's why I asked.
If you didn't want to help me you could've just not posted.

>>1849694
Well, the heating elements have resistances, listed on their datasheets. You have no idea what you're doing. Google some datasheets and, you know, look at them. Found in the first search I did.

Did you select a heating element yet?

I mean it's obvious you have no fucking clue what you are doing. Please keep insulting the correct answers you are receiving for free.

>>1849694
And how the fuck do i know what your capactitor should be? you haven't picked a regulator. HAd you bothered to do that, you'd have your answer...in the datasheet. Go read.

>>1849698
What heating element are you talking about? I have a soldering iron that I want to make a power supply for. Again, you're not under any obligation to reply if you don't want to help.

>>1849689
>winding ratio
why are you planning on doing the winding? do you have experience designing/building transformers?

overall the sketch looks good but you haven't provided any values, you need to choose the regulator to use (7809 for example) once you have that you can see what the requirements are for the regulator:
>Vin, Dropout Voltage ...
>max current
>quiescent current (if you need it to be low)
>input/output capacitance (can be provided in the datasheet as typical config)

once you have done that side you can then calculate the fuse

>>1849732
The greatest current capacity on any regulator on the site is 2 A. Is that cutting it too close?
https://www.mouser.com/datasheet/2/389/cd00000449-1795347.pdf
There are suggested values for the filters on page 7, so I'll use those. None of the capacitors I'm looking at have ESRs on the datasheet though, unless I'm not looking in the right place.
https://www.mouser.com/datasheet/2/445/860020672003-1725498.pdf
Thanks

>>1849732
And I'm not planning on winding the whole thing myself, but I've heard you can adjust some transformers by pulling a small number of turns off of a coil. There's probably a premade coil that works fine though

>>1849339
Firstly, BJTs switch on and off faster than MOSFETs, so where you don't care about current you should use an NPN (or PNP) instead. Which should apply to those two central MOSFETs around the 400kHz source.
Secondly, using a pullup resistor tied to a MOSFET gate limits the current going into that gate, so you should use push-pull transistors. 1M is particularly bad, as the gate charges can easily be a few hundred nC. ∆Q/∆t = I, so if ∆Q = 100nC and I = 24/1M = 24µA, then ∆t = 4.2ms. A standard BJT totem pole is likely the easiest way to go if you're not buying a transistor driver IC.
Thirdly, that circuit sim isn't terribly good, use a spice of some kind. LTspice is free and usable, though not exactly perfect.
Fourthly, those two resistors in the bottom right aren't doing anything as they're from ground to ground.
Fifthly, MOSFETs usually switch on much better at higher voltages, which typically range from 10-20V. This is probably true even if you've selected logic level MOSFETs.
Sixthly, pretty sure that top-right MOSFET is backwards. Even if it's turned off you'll be conducting through it's body diode. You'll also need to bootstrap it up to above its rail, else use a PMOS transistor.
Finally, how is that anything like MPPT? I can't see any feedback at all.

>>1849689
Don't forget the ripple voltage out of the rectifier. There's a nice equation for worst-case ripple voltage that you put current and capacitance and frequency into and get out a change in voltage, which might help. It assumes the sine is just a spike at each peak and that the capacitor ramp is linear not exponential.
Also don't forget the diode dropout (two drops worth) and the minimum droupout required by the 9V regulator for it to function. I'd give it another 1-2V at least, and you still need to add your ripple voltage before figuring out what the transformer windings should be. If you're winding your own, you should do a toroid, they're cool. They're also really hard to wind. Good luck!

>>1849738
He could easily use a power darlington and a TL431 instead of an existing linreg, giving him a dozen amps of room if he really wants to. TL431s are real good to have around.
I'd suggest a MOSFET instead, but he'd need one designed for linear action. I've heard about microscopic thermal runaway in normal switching MOSFETs run in the linear region.

single wire comms that only uses one wire, how?
frequency high enough for capacitive coupling of both ends to environment, while still retaining sufficient signal strength?

I'm just starting to work my way through my first project, which software would be good for a newbie to try to layout my board, at least just the circuit diagram, not even the traces.

>>1849886
KiCAD for everything. It's really good once you learn it. A single 1-hour tutorial should bring you up to speed.

i have a hakko 17b+ multimeter, a week ago i was measuring a resistor about 1.5k and couldn't get a reading, but the same resistor reads in a different multimeter. it measures fine today in the hakko though. does this mean it is damaged? i have checked the battery voltage and it reads 1.5v

>>1849689
epic magic box regulator

>>1849825
What you describe is essentially radio with a waveguide. In theory you could use the electrostatic force, but it would be susceptible to noise and require high voltage. I don't know of any systems that do this. "1wire" actually requires two wires.

>>1849899
>Hakko 17b+
You mean a Fluke 17b+?
Regardless, if its reading fine now I wouldn't worry about it. A lead could have been loose. Keep using it like normal until it happens again.

>>1849813
>I've heard about microscopic thermal runaway in normal switching MOSFETs run in the linear region.
That is caused by having multiple dies in the same package wired in parallel with no way of balancing each die with its neighbours.

>>1849825
>>1849923
What do you think a telegraph was?

why doesn't dave ever talk about vacuum chubes?

>>1849809
What I posted is just the buck converter part of the MPPT. Unless I'm misunderstanding (which is entirely possible given how hard I fucked the circuit up apparently) the feedback is going to be coming from the microcontroller, which is represented by the PWM symbol in the center of all the mosfets.
I was choosing mosfets because I thought they used less power (since no/negligible gate-source current). That's also why I chose such large value pull-up resistors, less current = less power draw but I see now I was misguided.

the two resistors at the bottom are part of a voltage divider to bias the diode so that the clamper would activate closer to 0 volts rather than allowing a larger negative voltage that might blow up the electrolytic capacitor (which is nonpolar in that schematic). I had it right in a previous sketch of the diagram but fucked it up when I added that ground symbol.

I tried implementing it in QUCS but apparently the mosfet model in QUCS is broken as fuck. I'll try in LTSpice. I just hate using it since it's so much harder to visualize how the circuit works.

>>1849930
yeah a fluke, got muddled up. thanks, i thought maybe it had to be re calibrated.

Hey guys, I'm building a light-up gundam and I need some help with the wiring.

These cell holders have 3 points of connection...how the hell do I solder it into a simple circuit?

>>1850022
What do you need help with, exactly? The +/- are labelled here.

>>1850022
If you're wondering about how to attach it to a board, first put holes in the board at the spacings shown in the PCB layout diagram. Push the part into the holes and then turn the board over to the back side.
Use the soldering iron to heat up one of the pins, then touch the solder to the heated pin until a little bit melts off. Place the end of the appropriate wire (positive or negative depending on the pin) into the melted solder and wait until it solidifies.

>>1849522
Thanks. I read just through Synth Secrets.
Great series of tutorials on sound design, but not much info on the actual electronic circuits used in analog synths.

I'm looking to make a little distribution network just around my workbench. I have finally found a center tap transformer that will allow me to make a proper +/- 12 V supply. Nothing too fancy, just a bridge rectifier, filter caps, and a 7812 & 7912.

I have some upcoming projects, each of which requires this +/- 12 V supply. But I am wondering exactly how I should distribute the power. I am thinking of three things:

1. Distribute the low voltage AC and have each project have its own rectifier, filter caps, and 7812/7912.
Pros: Each project will essentially have its own supply, and there should be little possibility of one project interfering with the DC supply of others.
Cons: More parts, probably more stress on transformer from more rectifiers.

2. Distribute rectified low voltage AC and have each project have its own 7812/7912.
Pros: Same as above. Perhaps less stress on transformer.
Cons: Distribution wire could radiate noise from the pulsed current.

3. Distribute the +/- 12 V DC from a single unit.
Pros: Least parts.
Cons: One project could potentially interfere with the DC supply of others. Noise could be coupled into the DC line running around the workbench.

Each scheme will require three wires, so there's nothing to be done there.

Any opinions?

>>1850115
I'll be real with you chief, I was obsessed with designing analog synthesizers too. It's what got me into electronics in the first place.
I stopped having a hardon for them once I learned how finicky they were.

The truth of the matter is, all analog synthesizers are are audio-frequency analog computers. Like, solve-differential-equations-via-laws-of-physics analog computers. Except their outputs are sound.
All of the circuits you described were incidental to the development of analog computers, necessary to get the results those doing analog computation were searching for. Only later did those same engineers realize in their off-time that they could be applied to audio-frequency circuits to make funny bleep bloops.

If you want to learn about those kinds of circuits, you're going to need to delve into the arcane and consult the eldest of boomers and books on the techniques of analog computation. Be wary though, even .1% of the convoluted heretical knowledge of the eldest is enough to shatter the mind of the average man.

I know all of this because I tried designing and building them myself, and soon realized that my knowledge of math and EE wasn't developed enough to understand how to build the circuits.
I have a personal mega library with some books on analog computers and music electronics. It might be of use to you: https://mega.nz/folder/xT5C2AhA#KEvjWz3WulwHOtuhRrDr4Q

>>1850131
Thank you.
Analog computers have always fascinated me, so I know what you're talking about.
I'm also into radio stuff, which is also where a lot of audio equipment comes from.
One of my favorite pieces of analog audio equipment is the vocoder, which can be used to reduce bandwidth needed to transmit voice over radio, or to 'encrypt' voice communication.

You're right though, analog shit can be pretty finicky, but I just find it incredibly interesting.
I guess I could also say I feel the need to preserve this arcane knowledge which is seldom seen or used these days, which is why it worries me somewhat that what information I can find seems to only be found on decrepit websites which could disappear from the net at anytime.

>>1849945
those use the earth itself as the second wire, i want to communicate to something up in the air, like through a single metal cable holding a helium balloon, where that won't be an option

>>1850189
What you're describing is an antenna and will pick up fuckloads of noise. You need shielding which can be used as a ground.

>>1850205
>an antenna and will pick up fuckloads of noise
i know, but if i just transmit ook at a certain high frequency and put that though a multipole band-pass at the upper end, it will still be usable. i just want to send an on/off signal

>>1850222
I think you need a transmission license to do that

also its more secure to use a wired connection anyway

>>1850223
i assumed 1 wire will transmit less noise than just transmitting rf, if not as good as 2 wires
i can't put 2 wires because its a cable that will be under significant tension
if just using a bog standard 433mhz or lora receiver is better ill just do that instead

>>1850222
No, it won't be, because you need to treat it like an antenna with a balun and tuning because you have no reference.
You're entering a world of pain

>>1850225
you dont need a return wire since you just need to apply a voltage across the wire to transmit the signal. pic related. you can use a transistor amplifier of any configuration to turn the capacitively coupled signal voltage into something useful which can drive a current

might be wrong here I wasnt able to quickly verify on google

>>1850230
theres no common ground between the two ends
single structural cable going up into a tree or balloon or building top
the only coupling between the ends is capacitive coupling to the environment
also your common emitter amp is missing a collector resistor

>>1850234
you can probably use a single wire system with both systems grounded to earth for coupling?

>>1850237
>grounded to earth
i cant ground to earth
thats the point
theres no earth to ground to up a tree
you shit

>>1850238
isnt the tree grounded to earth? you should try driving a nail into the trunk and grounding to it

>>1850239
its dynamic
it could be up any tree
it isnt permanent
no room for driving a nail in as that would defeat the purpose

>>1850243
if its mobile then why were you even considering a wired system?

>>1850244
because it will always be on one end of a steel cable that im on the other end of

>>1850270
maybe twist a low gauge return wire around it?

>>1850273
its under tension and needs to be spooled up

>>1850276
take two lower gauges of the wire, electrically isolate them, then twist them together to form a single cable, or use a coaxial cable if any can take the load

>>1850061
>>1850038

Sorry guys not sure if it was clear enough first time around. It looks like there are three pins, two + and one -. I'm also using wires, not a board. So I have one negative and one positive wire - do I attach it to two pins somehow?

>>1850285
The (+) terminals are both at battery +, they are the same thing, so you don't need to attach to both of them. You can if you want to, but you don't have to.

>>1850225
Yes, do LoRa or similar. They handle a lot of noise due to how the modulation/demodulation works. Trying to send a signal up a thick cable doesn't work they way you think it does. IF you have a shit ton of available electrons in the metal, they can absorb all kinds of shit. You're signal may never make it to the top without srs volts.

>>1850309
ok will do thanks
because the receiver may be obscured but not surrounded by concrete or even maybe metal i want to use a low frequency
the cable is still going to be steel so could it interfere with the radio?

>>1850381
well, technically, the cable will absorb the radiation directed at it, and possibly reradiate it.

Can you put the antenna where it's line of sight? If you have line of sight, you should be ok. To be technical, where you put the receiver doesn't matter, it's the antenna that matters. and you can get 1 or 2ft long cables pretty readily.

What are elliptic filters used for? And what does a higher order elliptic filter (like 9th order) do that a lower order elliptic filter (4th order) doesn't?

>>1850131
>>1850173
Put it in another perspective, it is so tempting to implement everything in a micro in software these days. It takes a huge power of will to avoid that route and go your own analog ways. Instead of building filters and envelop generators and what not, you can program them. Depends on what you prefer.

>>1850117
Option 3 would be most convenient imo. What projects are you planning to run simultaneously that would put noise back into the supply?

>>1850430
I don't think any of the projects will generate much noise. I'm just thinking in a general sense, a DC line running around the workbench could pick up noise. Right now the plans are to build a Wien bridge audio frequency oscillator and a total harmonic distortion meter. I was reading the manual for the "Sinadder 3" the other day and I figured the circuit could be readily adapted for this purpose. The Sinadder is a device used to measure signal-to-noise and distortion (SINAD) in FM radio receivers but the circuitry could also be used to measure THD for general audio equipment, which is my aim. So nothing that will really be generating a lot of noise.

If I buy ICs from china on ebay are they virtually guaranteed to be fake?
Will they at least work for hobby stuff?
Pic related only exists from strange chinese suppliers.

>>1850504
depends on where you buy it, it can range from a supplier that sells a totally different die that only passes the most basic uses to completely legit ics. In AliExpress you can spot the fakes with comments/reviews and their price (if the price seems to be too good to be true it probably isn't legit), isk about other sites like taobao or lcsc
also
>https://en.wikipedia.org/wiki/Motorola_MC14500B
what are you trying to build with something like this? seems way too niche

>>1850513
I want to build a breadboard version of pic related:
https://www.retrobrewcomputers.org/forum/index.php?t=msg&th=304&start=0&

Why are 5Y3 and 5AR4 so expensive but 5AU4 is readily available and is dirt cheap on ebay even though it is a beefier rectifier? Is that because the other two are used in some popular schematics? Thats the economics of vacuum tubes? I would never pay more than $5 for any tube lol. Just wanted to experiment with them for the heck of it.

can i multiply two signals by taking the log of them and adding them before taking the exp of them? because log and exp amplifier circuits are way simpler than a proper mixer.
mathematically it checks out so long as both signals are above 0V, which wouldn't be an issue with a little biasing circuitry or some virtual grounding

>>1850556
oh
i thought that using antiparallel diodes on the exp and log amps would allow it to work in all 4 quadrants
but it just lets it work in two quadrants
could still make it work with an inverting amp on one of them and doubling the circuit to suit, but thats not the easy quad opamp solution it could have been
maybe i can include the diodes in the summing amp to make it do its thing there and still only use a single quad op amp ic

>>1850556
I've heard about low speed mixers being made this way, but I can't remember where I read about them. I doubt mixers made this way could be used for RF purposes, if that's what you're aiming for. But if you're looking to multiply low frequency signals it should get the job done.

But biasing this will be tricky for sure.

>>1850575
for audio stuff, not rf.
biasing really is tricky, because that exp amp will hit the rails on every given opportunity, and the output amplitude is the product of the input amplitudes
my ltspice test circuit has the same diodes but 1meg on the log and 10k on the exp in order to not clip
for such a circuit to be practical id have to either limit the input amplitude severely, to the extent that its worse than using an ne612, or add an agc circuit somehow. neither are practical.

>>1850576
Yeah, making this a practical circuit will be tricky, especially if you are trying to make this work on a single supply. Making log and exp amplifiers is somewhat straightforward using a split rail supply. You just need to make sure that the input signal goes in the proper direction. Depending on the direction of the diode in the log/exp amp you will need a signal that either stays fully above or fully below 0 V.

I don't know the equations off the top of my head but I believe that a higher resistor value gives a lower gain. So your high resistor values are necessary to prevent clipping. If you need to do that in order to prevent clipping, this should be fine because the log relationship is preserved at any amplitude. Maybe you can just get the gain at a later stage and avoid the AGC or input limiting?

So I'm jumping right in trying to do my first project, but I'm learning completely from scratch, and I'm kinda getting overwhelmed. I'm starting to figure out vaguely how the circuit works, and I think I've decided on a few of the important numbers to design around, but trying to take the couple points I have and design the circuit around them is past me at the moment. Can anyone help me find a design for an induction heater where I can set the frequency to a specific speed?

>>1850656
Any reason you want to set the frequency?
Usually induction heaters are driven by a self-resonant circuit, so that the drive frequency can change as needed when the load on the inductor changes

>>1850656
As the other anon said, induction coils are usually driven as a resonant circuit to maximise efficiency. Maybe switching a capacitor or transformer winding in/out of circuit would be good to change the frequency while keeping it resonant, but outside of some fringe magnetic hysteresis cases I can't see a particular use for that.
But I would have a method for adjusting the power output. Maybe add temperature feedback too, though I've no clue what sort of temperature sensor to use inside a strong AC magnetic field.

This is a half-finished lunchtime break idea, but could you make a ring mixer like this with optocouplers, and avoid having to use transformers?

>>1847774
Can someone help me id this part? It’s got 32 pins and is about 2cm long

>>1851149
32 pin flat flexible connector?

>>1851149
>>1851152
Also knows as FPC connectors, and that style implies ZIF (Zero Insertion Force).

>>1851152
>>1851157
Found it, thank you for your help

>>1850538
Often used in old units, not so much any more.

bros where the fuck can i get JBC soldering tips
anywhere I can find it, it costs an arm and a leg in shipping
am a leaf btw
looking for chisel tip and the bevel tip
Am going to solder some SMD components soon (i hope) and don't have a bevel tip
i'd like a bigger chisel tip for higher thermal mass stuff

>>1850658
>>1850690
That gets kinda into where I get lost. I kinda get how an LC circuit works, but I know 100Khz is about where I want to target based on the size/material of my work, and how skin effect comes into play with it.

>>1851197
So you need to size your coil and caps such that the the range of resonant frequencies for a range of different loads (things inside the coil that will alter its inductance) will sit near that 100kHz range.

Fucking shit. I can't seem to be able to get rid of probing noise when i'm probing pcbs for milling.

Basically the pic bellow is a height map of the probed pcb (since pcbs are never perfectly flat, so you need to lift the endmill (drill) up and down to make sure the traces you mill have correct sizes, hence the need for the height probing).

if you run the probing routine several times, the resulting map should always look exactly the same, the problem is that i usually get one or two spots that differ, for example there would be small red spot in the dark blue area in the pic which is due to some sort of noise that makes the probe fire early. (The probe simply shorts pulled up input pin to ground by touching the pcb, the probe is literally just two wires, one connected to pcb, other to the endmill bit)

I tried to change the probe cables and used a shielded usb cable. I even tried to connect the shielding of the cable to earth ground, but the interference spots are still there.

How the fuck do i get rid of the noise issues?

>>1851228
this is an example of the noise, the probe fired too early, two times at the bottom and those two spots

>>1851228
I assume the probing is being done by the software that's running or interfacing with the machine? Not much you can do if that is the case and the problem stems from the software. But I'd see if you can slow down the machine while it's doing that, vibrations or resonances could potentially bump something just at the wrong time. How rigid is the machine anyhow?
There's always the good old oversampling technique; just run the levelling routine 10 times and average them all. Maybe a weighted average that eliminates obvious outliers.

Your probe is showing high, but your milling bit never accidentally plunges too hard or not enough, correct? How is the probe affixed?

Hi! I broke my radio scanners LCD and ordered new one from china to replace it. After designing and etching adapter pcb from 0.5mm fpc to unidens wider connector and soldering all those fucking small connections it works!

However the contrast is way too dark. It's readable when selecting lowest contrast in radios settings but it still looks shitty from normal viewing angle. Can I use a resistor/potentiometer with this display to reduce contrast?

The display is this: https://www.aliexpress.com/item/2053945961.html

>>1851240
it's not a software problem, the software just records the position when the probe says it touched surface, the rigidity is not an issue since it's a hard wood router, pcb doesn't even register as a load
can't really do oversampling with the software i'm using and there aren't many, or any alternatives really. All i can do is rerun the scan until it finishes without and noise errors which is annoying and time consuming

I googled up more and the ST7565 lcd driver seems to have an internal resistor divider for controlling contrast which means that the contrast is controlled by serial commands. As I cant modify the radios software, is there a way to change the contrast using resistors?

t. >>1851248

>>1851265
* external resistors

>>1851259
If you can somehow get the raw data from the probing routine (in some temp file somewhere maybe), you could chuck it through a 2D low-pass filter in a python script or whatever before somehow getting it back into the machine.

>not software
>not rigidity
So what, is it in the firmware? A faulty electrical connection? It has to be somewhere. Maybe it's EMI or PSU transients, and adding ferrites, shielding, and/or caps to your cables and terminations will fix the issue. But since those high-spots are right next to one another I assume it's not an entirely random error but rather a somewhat systematic error. Unless that's random chance and you usually do get a spot or two in random locations.
Does anyone else have the same problem as you?

>>1851265
>the ST7565 lcd driver seems to have an internal resistor divider for controlling contrast which means that the contrast is controlled by serial commands
Are you sure it isn't an analog input? Is there a block diagram on the datasheet?

>>1851268
>Are you sure it isn't an analog input? Is there a block diagram on the datasheet?

It amazes me how often people post questions when it's so much simpler and faster to just look at the datasheet.

>>1851268
>Are you sure it isn't an analog input? Is there a block diagram on the datasheet?
It's well explained e.g. there: https://edeca.net/pages/the-st7565-display-controller/

The ST7565R/P datasheet didn't really help me at least.

>>1851228
>>1851230
>wasting time milling pcbs when you could just order them online and focus your efforts instead on milling front panels, enclosures, switches, brackets, housings, etc

>>1851303
it takes almost a month to get them, if you want to shit out a fast prototype, or need to quickly test out alterations and such milling is the best method
i'm not going reoder a stack of 10 and wait a month every time i make a new revision

Why are there some many different analysis types? Which is more practical, node or mesh or loop analysis? What kind of analysis is used when, for example, in a voltage divider bias, where R1 and R2 are "seen" as R1 || R2 in parallel? Is that thevenin?

>>1851308
all analysis types are based off KVL/KCL/ohm's law. They are just different applications of those.

rolling for a nice project

>>1851307
that's fair enough. i thought you were milling them for final design
which services have yo utried? I ordered some from OSH park its been close to a week with shipping charge out the ass
i might try pcbway next. jlcpcb seems to have long or expensive shipping that you describe fuck

>>1851636
can let you know that pcbway will quote you a long time, but from when i place an order till when I get them takes a week, tops, granted im in CA.

>>1851668
>quote you a long time
Really? I get quoted like 3 or 4 days with the quote i'm getting right now
that's with DHL though. do you have to pay extra shit with DHL? the few times i've dealt with DHL they always charge extrta shit

>>1851704
Is that total time or just shipping time? Just to be clear, im talking total time, build + shipping.
The quote pcnway gives you is the final price, and I used DHL. maybe they are quoting less time or maybe have less orders due to COVID?
either way, I have found them to be extremely based and use them all the time.

>>1851706
I'll have to see again. I've only put my gerber in but not gotten to the pay part which is where you'd probably see a bettter breakdown of that?
For some reason i skipped over pcbway and went with oshpark because they're made in north america or something and i preseumed they'd be faster
but they charging me an arm and a leg for fucking shipping.
I'll take your account into consideration. Just Every time I've had shipping with DHL i get loaded with extra fees at delivery

>>1851308
>>1851310
Millman's theorem is an easy way to solve some otherwise more difficult problems. IIRC it applies well to analysing some transistor circuits with the equivalent model of the transistor substituted in.

So I just took out my Redmi note 7 battery using a hairdryer and a thin metal tool to take out the battery.
I kinda ripped open the black outer casing and you can see there is a tiny scratch on the foil on the inside.
It smells like acerin, not too bad of a smell. I'm thinking maybe that's just the glue. But if not, is the battery damaged and should I throw it out? I did read someone say their battery smelled the same but they took it to a bettery place and they said it was fine, so he put it back in and worked fine.
What do you guys recommend?

>>1852031
If you pierced the Al then it's fucked.
If not, it's maybe, looks like a lot of physical damage to me.

IDK about that device specifically but if the battery is not exorbitant in price I'd replace it while you have it out anyways since it's already out.

I found this tutorial that turns your headset into a mic. How does this work?
https://www.instructables.com/id/Build-Your-Own-Microphone/

>>1852065
Speakers are microphones and microphones are speakers. Most speakers are a coil of wire (electromagnet) mounted on a diaphragm relative to a stationary magnet that voltage across the coil produces a force against. By moving the diaphragm manually or with sound waves, an opposite voltage is induced across the coil. Such is Faraday's law. This type of microphone is called a dynamic microphone, but most compact microphones you'll find will be of the electret variety, which technically can also be made into a speaker. Common electret microphone cartridges have their own preamplifier built-in to their case, in the form of a single JFET, so to turn one into a speaker you'd need to desolder this and send your signal directly across the electret condenser. This preamp JFET runs off the low voltage phantom power from the microphone jack, so you might end up with some DC current through your earbud speaker if you go through with the conversion. The functions of electrets are beyond the scope of this explanation.

This should go without saying, but you shouldn't expect good audio quality from some shitty earbuds, or any earbuds actually. At least not without a preamplifier close to the microphone itself, and maybe a pop-filter and an anti-vibration mount.

>>1852065
a microphone and a speaker are one and the same, just as how a motor is also a generator.
If you apply an external electrical signal to it, it will convert that signal into an acoustic signal/waves
if you apply no external power put an acoustic signal to it, it will generate an electrical signal in turn

it depends on the construction of the headphone. It can generate the electrical wave capacitively (thin electrical membrane like an electrostatic headphone) or inductively (coiled wire + speaker cone)

>>1852078
fuck you

>>1852065
It works because microphone is somewhat similar to headphone. You can also play music on a mic and so on but it sounds shit. Just buy a cheap mic from china and it will be a lot better.

On the topic of microphones, I bought a microphone preamp module from alibay for around $3 (I think it has an AGC built in), which I've heard good things about. If it really does make my shitty electret capsules sound better, I'll be sure to mention it here. Sure beats buying a BM-800 and giving it phantom power on its balanced audio output only to put it right into an XLR-to-3.5mm adapter.

>>1851415
Dude that's a very broad question but here are a couple random ideas:
>Curve tracer. The concept is easy to learn but will make you think, plus you get a fun instrument to check out that can be very useful. Linearity of devices is crucial.
>An audio level meter using magic eye tubes. Did this the other day and it looks cool plus it's easy. If you don't like tubes then LM3915 in bar mode. Easy. Cheap. Kills time and who doesn't like flashing blinkenlighten?
>Signal tracer.
>50W/chan. audio amp with LM3876. Cheap and phenomenal performance for what you pay but the power supply may be the most expensive part.
>Dual tracking power supply with LM317/337; bootstrap for extra current and add current limiting for a hair pulling good time.
>Buy and fix an old radio, I'm doing a Zenith TO and it is a lot of fun but be prepared to hunt for tubes or parts. Avoid germanium stuff unless you are comfortable cross referencing components as NTE is a ripoff and the Russians make better germanium devices.
>Find a POS toy like a tickle me elmo and circuit bend the hell out of it...or...embed light sensors in the eyes and replace the circuit with something more interesting like a delayed whispered voice after it detects someone in the room or it screams on sight. Be warned: your unfortunate victim will probably destroy it or will br very mad with you.
>A delayed chirp box...make a circuit that chirps like a bird every 45 mins or so and hide that box. This thing drives people batshit and is fun to watch. April fools becomes a little more entertaning...
Hope that gives you some inspiration.

>>1852177
Not him but
>power supply
sounds simple but can be a massive rabbit hole esp if you wanna try to incorporate professional style features and shit instead of just the pedestrian tier constant voltage and curent modes. And even those there can be things you want for them that make them next level. like high precision and accuracy

hi /diy/, i'm a tourist from /g/
is this the correct general to ask about usb connections?
i'm trying to convert a keyboard into usb-c, and failed
i just learned that usb-c uses resistors to announce whether it is host or subdevice and that i need to solder a 5.1 kOhm resistor to make the keyboard a "subdevice"
my question is where do i solder this resistor, and which direction should it be?

>>1852198
what does the keyboard currently use

>>1852210
currently it is not responding as i just soldered the type c wires to the corresponding colors
previously, it was using a 2.0 type-a cable with a 4 pin connector to the pcb, like in the pic

>>1851228
okay time to put on a thinking cap
the probe pin is kept high by an internal pull up and the probe shorts it to ground, so if the probe misfires by firing too early it means the pin charge got drained by EMI. so adding a simple cap between the probe output and ground will cause the internal pull up to charge the cap so in order for the probe to misfire, the emi would have to be strong enough to drain the cap. the down side is the probe will take a longer time to go back to ready state before the cap gets charged after a trigger but that is negligible
so what cap value should i use? i have 4.7nf, will that be enough to resist EMI? or should i put something a lot bigger there like 1uf? but that seems like an overkill

>>1852211
>>1852210
nvm i’ll just cut off the end and solder a type-c otg male
hopefully that’s going to do the job

How reasonable is stepping up a lithium ion battery at 20A input to 12V on the output? I'm not finding any good premade modules for it, but I'm assuming that's just because usually at that kind of power you'd usually just run a few li-ion in series instead of stepping things up, right?

Does anyone know what kind of steel typical cheap power transformers are made of? I mean your average old fashioned linear step up/step down transformers.

>>1852306
you mean the magnetic core?

silicon steel is usually used because of the small hysteresis losses and high magnetic permeability

>>1852315
Yeah silicon steel, I was wondering about what kind of steel, like M5 etc. probably a much lower grade. Just wanted to estimate the permeability but since it is non-linear and varies with H, I'd like to find some typical graphs B(H).

>>1852198
https://youtu.be/V-vFtiDYiIw?t=402

These will become my bike's front & rear lights. The front light has 2*5 mm indirect light LEDs for "low beam" and 3*5 mm for "high beam".
The rear light has 8*3mm LEDs for "low beam" and 2*5 mm for "high beam".

High beam

Stereo I just got running ;)

I put my own 110-5Dcv adapter in, I don’t trust those blocks- I swear they’re 5.2-5.4v so they wear your boards.

>>1852460
what is indirect led lol
well done on being a complete nonce trying to blind pedestrians and other road users. what research have you done to determine optimal light pattern and brightness? or you just throw whatever shit you have laying around into an enclosure
why the fuck does a rear light need high beam? a fog lamp you mean? here's a tip: if it's so foggy that other road users can't see you don't go out in it. head and tail lamps are some of the very few parts of motor vehicles that have their own international standards to meet because they are vital safety equipment. not some joke to be fucked around with. no that 99.99% of commercially available cycle lights are any better than whatever this is. at least it doesn't flash right? good job.

>>1852460
What mounting hardware are you using? Metal hose clamps? Are they waterproof?

>>1852563
Even on high beam it's probably dimmer than most car rear lights, and it's more diffuse than it could be, I'd say it looks fine.
Indirect probably means shining through a reflector or lightpipe or diffusor, pretty self explanatory

Are there any rules for choosing frequency bands in a vocoder?
I've settled on the circuit topology I'd like to use, but I haven't yet decided what frequencies to use.
Is the specific frequency selection actually critical, or is it mainly just important to have many equally spaced frequencies throughout the audio spectrum?
I've also noticed that no vocoder designs use frequencies closer than 1/3 of an octave.
Is that just because audio quality increase is minimal compared to the increased filter roll-off required?

didnt see anything in op unless im a retard.

but what are we saying the best budget oscilloscopes are these days? or just better off to buy a nice one second hand?

>>1852621
http://musicfromouterspace.com/index.php?MAINTAB=SYNTHDIY&PROJARG=YOURANALOGSYNTH/YOURANALOGSYNTH.php&VPW=1910&VPH=846

>>1852031
honestly its not worth risking it. just get a new one

>>1852675
I am aware of the MFOS vocoder, that's one of the designs I referenced while working on the design of my vocoder.
I've also looked at the Paia, Okita, Elektor, Moog, and Hoerold vocoder designs.
No two vocoders use the same selection of frequencies, which leads me to believe that it's not critical, but I wouldn't mind a second opinion.

>>1852674
There aren't good new oscilloscopes under $300, 2nd hand is the way to go. You should be able to get a good 2nd hand scope for $50 or less, probably an analog one. Only upgrade when you can shell out the money for a decent 4+ channel 50+MHz digital scope.

The chinese make USB oscilloscopes that use your computer as the display and for data processing, and they're relatively cheap compared to a proper digital scope, but I'd avoid them because the software is pretty shit and there's the ever-present risk of damaging your computer from an unfriendly signal on an input.
You may see chinese clones of the DSO138 and DSO150, and while they might be fine for some very rudimentary low-frequency work, they're only single channel so they're next to useless for a lot of stuff. They're nice DIY soldering kits though, if you get the DIY version.
Probably better off using a sound card as an oscilloscope than getting one of those DSO kits, though doing so comes with the same issues as the USB scopes.

You'll also want a function generator, one with a pulse output, variable DC offset, and a few different waveform shapes. AM and FM probably isn't necessary, but a frequency sweep is nice to have, pretty sure you can make bode plots with one of those, with your scope in XY mode. If your function generator is electrically isolated relative to your oscope, it's much easier to use it for curve tracing.

What would cause this failure patten in a TV backlight? They flash on and off but always the same LEDs. Do you think the LED strips or the power board need to be replaced?

>>1852705
LEDs themselves only fail such that they no longer turn on, so I'm thinking power or control systems have failed here

>>1852709
Before I opened it up I checked the flashing online and many sources indicated that flashing could point to a short on the LED strip. The top 2 rows are a separate circuit from the bottom 3 and they're all off so that makes me wonder if there isn't a short in there somewhere.

>>1852712
if the other two strips are working fine then troubleshooting logic does indeed indicate that something is wrong with the third strip.

if you have a multimeter you can measure the voltages across the components while it is energized to check for shorts in lieu of a DRC

>>1852714
There's no good way to meter the LEDs themselves and the power board looks and meters fine. I think it's worth $40 to try replacing the LEDs then if that doesn't work another $40 for the power board.

>>1852719
Are the LEDs parallel or series, or some combination? See if you can draw out a circuit diagram, it should help with troubleshooting.

Is there a covert way I could fry a drill? I have a Harbor Freight drill that I really need replaced at work buy my cheap-ass boss won't get me a new one because "it still works". Meanwhile he has his nice Makita drill... I could just get my own, but the boss is really weird about us using our own tools. He claims it's a liability thing.

>>1852189
I know but it's really just an idea put out there. A lot of people don't appreciate the finer nuances of linear supplies. Probably why Xantrex is/was so stingy with schematics.

>Finally got my discrete LM13700 working
Aw yeah, now I have a backup plan if they ever go out of production.
Also: I never really realized that the LM13700 was like 90% current mirrors until I actually set down to copy it.

Now I just need to figure out how to bias my Gilbert Cell so it isn't complete shit.

>>1852956
lmao just use photoFETs like the H11F1 instead

>>1852958
I'm confused, what does a opto-isolator have to do with transconductance amplifiers or analog multipliers?

>>1852958
Also, I just noticed that the H11F1 is marked as obsolete, so how would that help anyways if the concern is things going out of production?

>>1852964
It's an analog optoisolator, where the output is a JFET, basically a variable resistance. By changing the current through the LED, you can change the resistance through the JFET. If you include this JFET as a part of a feedback loop, you can make a variable gain amplifier, variable frequency filter, etc. The optoisolation means you don't need some sort of floating drive circuit to give the JFET a certain gate-source voltage, hence making it possible to use in a variety of different circuits regardless of the actual DC voltage at either terminal.

>>1852965
You can possibly make your own with normal optos and JFETs. It was kinda a meme suggestion desu, but still valid and still a neat part.
Also I think the NE612 is still being made, though it has its issues.

fucking word filter

>>1852967
Ah ok, use the opto-isolator like a vactrol.
That works, but it seems pretty sloppy compared to using a proper transconductance amp, even if the amp is made from discrete transistors.

As for gilbert cells, I know the AD633 is still in production, but it's like a $10 part even in quantity.
When you can buy a matched pair of transistors for a quarter, it just seems more economical to make a discrete gilbert cell, especially if it's not being used for radio frequencies.

>>1852974
>a matched pair of transistors for a quarter
In what package, just a normal 8-pin SOIC or something?

>>1852981
Looks like it's mostly 6-pin TSSOP

anons, I destroyed hard drive PCB.
Happened years ago when I hot swapped a drive into a shoddy molex to SATA power convertor. sparks flew, smoke ascended, pants were shat
I presume if these parts burnt themselves out the rest of the board is probably fine? I certainly can't see anything else out of the ordinary.

Do I just type numbers into aliexpress and buy new PCB, chinaman sneezes on the new PCB, desolder BIOS chip from old board, put onto new board, contract corona, and profit?

>>1852996
and this is what it's supposed to look like

>>1852996
I've never attempted that, but you should know the saying:
'Molex to SATA, lose all your data.'

>>1852996
That is pretty nasty, damage to the board might have occurred. What you described would fix it but since you had to ask I assume you lack the technical skill to solder at that kind of scale. Replace HD is your best bet unfortunately.

>>1853010
>>1852996
Whoops I misread. Swapping the chip may save your data but it may have been fried from the surge. What I said about your soldering skills still stands.

>>1853009
top kek

>>1852996
I'd read the pinout to see what's on the pins that have fried shit on them. Get your bearings, see if you can infer what caused the fault.

>>1852252
holy shit i think it worked
sometimes i'm so smart it scares me

>>1852996
overvoltage damage doesnt just occur to one or two parts, when there's visible damage like that it's quite likely you've shot-through every transistor on the board even if they dont look fried.

basically give up

>>1853037
The internal pullup may be too large so using a smaller one in parallel with it might be a good idea. A cap that the pin has to discharge when turning off means a bit of a current spike, hence why I'd prefer a smaller pullup.

thanks fellas
>>1853009
it's true. mistake one only makes once.
with a lot of hindsight, just the idea of even turning 4 pins into 15 just seems suspect...
>>1853011
I understand. For me it is worth the gamble. Donor boards are $6.50 from aliexpress. versus a data repair company which here starts at $400. So even with buying a hot air gun, flux, etc I am still in front.
My soldering is terrible, correct. Hopefully I can learn enough from youtube to not make a mockery, then I practice pulling and replacing on scrap boards lying around.
If not, it can't be helped. it seems like fun enough.

It's more of an 'electrical' than an 'electronic' question, but maybe someone will know
At my house if there's too many devices going on (like oven plus hoover plus washing mashine plus 2 PCs) there is an outbreak and fuses break the electricity in the household.
Well it doesn't happen everyday (because we don't always use this much electricity), so we didn't bother to fix it. But sometimes it does and it's annoying. How to increase the power network capacity? I'm clueless. Sorry for poor terminology

>>1853112
Are you tripping the master breaker?
If the master breaker is tripping then something is definitely faulty.
Otherwise, unless all of your stuff is on the same circuit you shouldn't be having issues.
The Oven should have it's own circuit, as should the washing machines.
Two PCs on the same circuit shouldn't be an issue unless they're like 1000w beasts.

>>1853112

if you have fuses, buy stronger ones (e.g. 20A or 25A instead of 15A). if you have breakers, you do the same, but it's a bit more complicated so search youtube for how-to videos.

>https://hackaday.com/2020/06/29/updating-the-language-of-spi-pin-labels-to-remove-casual-references-to-slavery/
What a load of bullshit.

I have one of these cheap battery powered Halloween neon lights from target but I’d like to modify it. Can I safely convert it to be usb powered? I’d also like to paint it a different color. It doesn’t get hot. What paint would be safest still for electronics and would be opaque enough for light to shine through?

>>1852878
Exceeding amperage? What happens if you put in a vise and turn it on? Do HF drills have an overload protection? If it does then it is a decent drill and maybe you should keep it.

>>1853145
but i like saying "mosi" and "miso"

>>1853145
It's amusing how Orwell of all people, predicted this neo-totalitarism so well

i had a dream where someone left my dmm on and it ran out of battery
the leads were also left in the current plugs

>>1853145
>People unironically arguing that primary/secondary is more descriptive
How? Primary/secondary is literally the most vague terminology I can imagine.

>>1853322
I had a dream that a cute, skinny, crazy asian art chick threatened to cut off my balls

>>1853376
Decent. I dreamt lucoa threatened to stick an electrified baton up my butt. It was...
>...electrifyi...
Pretty gay ngl

>>1853341
The “controller” “peripheral” terminology sounds fine to me. Not that I think we should attempt to rename an entire standard for such a trivial reason.

What kind of wire do you prefer for which projects? Silicone vs PVC vs teflon? I like the heat resistance of silicone but it is kinda too flaccid to my liking. And I've never used teflon I think. PVC is Ok but you gotta be quick or go for a more heat resistant insulation type, which is a hassle to check cause I always forget the specs.

I want to spice up my RC project with EL wire twisted alongside my power and signal wires. Is this a bad idea from a noise perspective? EL wire is basically coaxial, but it still has a few kHz and a few hundred volts going across it.

Also now I’m wondering if an electroluminescent phosphor could be used as a gain medium for a laser.

I'm working on an old amp that uses 120 watts of power at 117V. I was thinking of bringing it up with a variac and using a dim bulb tester in line with it. Would a 200 watt bulb be reasonable to use in the tester? I haven't used a dim bulb tester before, but this amp is sort of complex and was a bit of a rat's nest so I don't want to take any chances just in case I messed up somehow.

>>1847774
Where does /ohm/ acquire dirt cheap bulk wire for projects?

I'm tired of using small salvaged strands, I just want to say fuck it and get like 200'+ of a pile of sizes

>>1853554
I just bought like $50 of silicone wire from aliexpress
But I've heard good things about cat5 cable, especially the solid-core stuff for breadboarding. Wire-wrapping wire is also good for that, but it's commonly enough used as everyday hookup/breadboarding wire that I don't think you'll get it cheap just because nobody uses wire-wrapping anymore. But at least it means it's still being produced for those 3 people who are still wire-wrapping.

Can I ask all of you for advice? My grandparents live in a apt that needs 6000-9000 btu. When they first got the apt, they’ve had no problems with ACs. The last they got before the one they currently have (which broke), was around 9K-10K BTU, they can’t remember. That 9K/10K BTU causes sparks to fly at the electrical outlet and got them scared, which then prompted them to get a 5000BTU ac which died 3 years ago. Now they are looking for a new ac but before I get one for them, I have a question. Does higher BTU mean it’ll fuck with their electrical outlets and cause a shortage? If not, why did that happen before? context: The apartment was built in a building around the 40s. They use a electrical multi outlet to connect stuff. I need to know this because that’ll make me decide whether I get a 6K, a 7K, or an 8K

>>1853580
what is wire wrapping?

>>1853580
>>1853554
what's the best gauge to stock up on for general electronics?

like 16 gauge for RC and shit right?

bros, I need 6ft of wire for a 12V LED project and according to online calculators I need a 20AWG wire (or 22AWG wire if >2% loss is acceptable).
if I use a 4 core 24AWG wire and combine it into 2x2 core wires, is that equivalent to 22AWG?

>>1853631
if you only need 6 feet why not just go get some 20awg wire from lowes or whatever?

they cut that shit to size

I live in an apartment in North America that has an electrical panel with old style fuse bulbs in it. Some of the rooms in my apartment do not correspond to any of the fuses (but they still have power). I am 99% sure there is no other fuse panel in my room and nothing anywhere else in the building accessible to me.

>Is it possible that there are unfused circuits in my apartment?

My building is ancient and when I spoke to an electrician who was in the building for some other reason he said it wasn't likely (but offered no explanation for the rooms having power with the fuses removed) and basically just ignored any attempt I made to try and talk to him. Landlord told me he doesn't know and "can't you just plug whatever into the outlets? Why do you care?"

Wouldn't it be a safety violation (even if the building is ancient) to not have the room circuits going through a fuse? Its gotta be somewhere right, just hidden in the building somewhere.

what gauge wire should I use for 3.2 amp?
>https://www.powerstream.com/Wire_Size.htm

Says 16 is up to 3.7, would I be cutting it too close?

>>1853607
A method of compact point-to-point wiring used before printed circuit boards were mainstream. Probably used after they became mainstream for some time because their connections are easier to reroute, provided you can decipher what you're looking at.
Google some images of it, it looks pretty funky. IIRC it relies on cold-welding of the copper wire to the gold-plated square pin for a solid electrical connection. Either done with a simple hand-turned tool, or a motorised wire-wrapping gun, both put half a dozen turns of stripped wire around the pin, give or take a factor of 2.

>>1853623
20-24 is perfectly fine for small signals, heck even up to 30 is probably fine so long as it's mechanically strong enough. For actual current-carrying wire, look at the ampacity of different wires. 20-16 is probably good for general use, up to an amp or so.

>>1853631
Go to the wikipedia page for american wire gauge (awg). Then calculate the effective resistance of 6ft of 24 gauge wire, and see if it's more or less than that of 6/2ft of 22 gauge wire.

>>1853649
You're better off directly calculating the heat loss. There are two things to consider, whether the wire is getting too hot for the insulation or the surrounding components (also a function of the wire's thermal radiation/conduction), and whether the wastage is significant to the power budget of your application. In other words, if you've got a battery-operated circuit, you should err on the side of a larger conductor.
I find ampacity goes up at a slower rate than price, so I usually err on the side of a larger conductor anyhow, provided I've got ample selection to do so. Bought a few metres of 12awg a week ago because that's the biggest an XT60 is supposed to handle. Silicone insulation too, because soldering onto those cups would probably leave PVC insulation as a bit of a mess.

>>1853642
easy way to test it, short the outlet wires to see if some fuse blows or if the apartment breaker trips

>>1853670
Or he could hold a hall-effect sensor up to the fuse and plug kW heaters into all the outlets, seeing which ones don't give a reading on the breaker, or give readings on a different fuse. Might even be able to clip a current transformer around the fuse itself.

>>1853678
yeah, but he would have to buy that stuff and learn how to use it, when my way is completely free, easy to do, and requires no extra equipment

>>1853684
>completely free, easy to do, and requires no extra equipment
If by "completely free" you mean "requires like $50 of replacement fuses", then sure. He needs to test multiple outlets, after all.

>>1853704
>requires like $50 of replacement fuses
lol what? nails cost like one cent a pop

my lora modules finally arrived
can't wait to find out if their legendary transmit range is really real

>>1853590
>>1853590
>>1853590
Someone please respond holy fuck

>>1853805
Get the outlet replaced. Does it even have a ground pin or is it old enough to be 2 wire only?

>>1853805

a house with 80-year old wire needs a complete re-wiring.

if that's too expensive, you can just replace the power jack. dunno about your country but here they cost around a dollar. that should eliminate any sparking. and then you can get a 10K unit which is the minimum size you should buy for a house. 5-8K are for single rooms, and are pathetic even for that.

>>1853623
22awg is my favorite

>>1853834
why? my house is petty old (the wiring is made from aluminium) and i never had any problems

>>1853112
Sounds like the wiring in the house isn't too great. Ive seen houses wired up such that everything loads down one of the HV legs that come in. If you are blowing multiple breakers at the same time, you may need to get your main breaker box checked out. Something may not be wired up tightly and overloading current, or a loose wire can be grounding out.

>>1853139
NEVER buy larger fuses/breakers. If your system is blowing them, its pulling too much current, and for a reason.
If you have a normal 20A breaker on a 120Vac line, that is 2400 Watts. Dropping in a 25A breaker is another 600 Watts for total of 3000 Watts.
If something is pulling 2400W, you do NOT want to give it the chance to pull 3000W. Thats not even taking into consideration the limits of the outlets, wiring, ect...

>>1853145
People have been after this for a long time. Back when you had IDE ports on your computer motherboard, you could have two hdds on one cable... the Master and the Slave.
>But muh feelings
Holy shit I hate this fucking planet

>>1853550
Unless you know the topology of the power supply, using a variac is a bad idea.
What would be your goal for doing that?

Are these 3 circuits functionally the same thing?

>>1853145
I think what is more problematic is the fact that the micros, which do all the work and don't get paid for it are black

how pants-on-head retarded is it to use a paperclip as a shunt resistor

>>1853905

yes in theory, no in reality.
real LEDs, like real people, have differing characteristics. whenever you put 2 or more in parallel, one is gonna be stronger, faster, holier, more sexy, more in tune with their feelings and privileges.

the result is that they dont share the electrons equally, but each according to his needs, so your calculations go out the window. the third drawing is the only equitable way to share the electrons.

>>1853952
So, what you're saying anon, is that one of the LEDs will be a flamingly gay LED who is confident in their sexuality?

Is this how RGB LEDs are made?

>>1853952
I honestly can't tell if that's a real answer or pure political satire, either way made me chuckle.

I'll assume it is, that being said, how much of a "buffer" is recommended for a resister then? Like ratio of amp draw of the LED to the max amp of the resistor?


Also just to make sure im not being retarded on the resistance,
http://www.ohmslawcalculator.com/led-resistor-calculator
Is what I used.

(not a real circuit just brainstorming for my actual one)

If the source is 12V
The Current recommended by the LED is 2A
And I use a 1 ohm resistor...
But I don't know the voltage drop of the LED

It should come out to right at 20 watts to the LED constant, correct?

>>1853962
>But I don't know the voltage drop of the LED

the values are pretty standard depending on the color of the LED. see https://en.wikipedia.org/wiki/LED_circuit or elsewhere.

>>1853905
If you have 20 watt LEDs you really should be driving those with a constant current source.
A simple resistor isn't going to be sufficient, especially when those LEDs start to warm up, since the voltage drop is temperature dependent.

Anyone have any recommendations for cheap >=10amp DC power supplies?

>>1854026

so cheap, you can pick 'em up at the thrift-store from under $5, or free on the curb. you (or people you know, assuming you know people) might even have one in a closet in an old pentium 4.

>>1854032
Sorry I meant an adjustable one, for testing and such.

>>1854033

ah, a lab power supply. 10 A seems a bit of overkill, but ''to each his own''.
RD tech makes these geeky variable supplies that are fed from another, fixed, supply. they sell various sizes.
https://www.aliexpress.com/item/4001053200176.html?spm=a2g0o.store_home.slider_2757819.0

Could you go fairly over a resistors rated wattage if you attached it directly to a heat sink?

The wattage ratting just means it's going to generate a lot of heat, right?

>>1854040

sure, if you can drive the heat away. problem is resistors are NOT good at that. they're often round, so not much surface contact. and the material is ceramic which is not a good conductor of heat.

>>1853670
>short the outlet wires to see if some fuse blows
This seems extremely dangerous. Like I asked, if its not fused couldn't this basically cause a fire? I care less about where the fuse is so long as the likelihood that there is one is high. If it blows while I'm doing normal stuff, I will call my LL and he can foot the bill of sending an electrician because I don't know where the fuse is. I just wanted to know about this from like a legal standpoint; how likely is it in an older building that such a thing is possible?

Are 0.33%/K temperature compensation resistors still a thing?
I can't seem to find any on mouser or digikey.

>>1853655
So for 3-4 amps over maybe 1-2' tops, what gauge would you recommend?

>>1854331
12-18 gauge, depending on what you value. I just go big because wire is usually relatively cheap anyhow.

How easy would it be to make a fake alarm indicator light for a vehicle? I'm not even sure how often or fast it should flash. I saw some online for sale, but a lot of the comments on the items said they either blinked too fast or too slow. Is this something I would need to use a chip for or is there an easier or better way to go about?

Sorry I'm being retarded about such a fundamental thing.
But do you have a chart or something that isn't complete fucking shit?


I've googled all around and have found charts that say everything from 12 to 18 is the minimum required for a load of 36v 4amp.

I have other wires I need as well and id rather check a chart than be a bother constantly.

Total retard here(despite graduated in electrical), so i am helping a relative of mine running a lodging. Somehow she messed up the design for electrical lightings so the terrace's lights somehow connected to one of the guests' room. It's jumbled in one single MCB box. The worst thing is terrace lights don't have switches either so if i want to light up the terrace i have to light up the guest room's light.

I am thinking of re-rerouting those cables to a single panel/box. I am not sure how to handle this shit because relative wanted the place look "presentable" for the guest and less engineering shit. I am looking for recommendation for product that can be used for panel and switch and somehow doesnt look like telephone box. Or MCB box and connect them to switches later on.

im fixing some industrial equipment. the problem is the switch controlling a motor doesnt work when switch is placed to position "3".
i found pic related regarding the switch (T0-6-158). im well beyond retarded when it comes to ac, three-phase motors and have no fucking clue what im looking at. i managed to decipher the table with crosses (if i understand correctly, this shows which contacts are energized in which position), but ive got no fucking clue what "0-(B)delta-(A)Y-(B)-YY" is supposed to mean. i understand that these are different ac motor configurations, what why are there 5 of them? the switch has 4 unique positions. why second to last is simply (B) without configuration?

shenzhen io is a fun game, makes me feel like im actually making something for once
the code reminds me of an assembly language of some sort, but ive never actually looked at assembly language long enough to know if these commands are dummed down significantly or not

>>1852911
I'm trying to design one myself right now
Trying to make a switchng tracking preregulator just to make it slightly more efficient but dat switching noise
But also, scared of it oscillating
Won't really know until I commit it to PCB either which kinda sucks

>>1854039
Not him but how clean are the outputs?

I'm so retarded that I lied about having experience with electronics at a job interview. Half a year of working here (programming) I get the job of creating a prototype of some kind of stabilization device.

I love this job, but damn, is it reasonable to learn to solder and understand wiring schematics in a week? I have done a lot of arduino projects at least.

>>1854480
Filtering, filtering, filtering. Did I mention filtering? For real though, pay attention to your capacitors. Ripple current, esr become very important. Anaylze your feedback circuit carefully. Hysteresis may help but avoid anything that can create a positive feedback loop. What control IC are you using? I decided to be a smart ass and do things entirely with opamps/analog circuitry. Shelved for now as I can't seem to focus on one thing at a time and ended up restoring a radio and making a stupid single ended tube amp with a pair of 50L6.

How the fuck does grid tied inverters work? How do you even model that? The network (a source) and inverter (another source) and the load all in paralell? How does power flow from the inverter to the network if the voltages are the same? Do they force their voltage to be sligthly higher than the network?

>>1854480
Just put a current source whose output goes to the adjust/trigger/control/feedback pin of the switching regulator and that connects the switching output to the linear output. It worked for me.

>>1854534
reactive fuckery

>>1854479
>if these commands are dummed down significantly or not
they are. but still a decent way to get used to assembly's hyper-reductionism i guess

>>1854317
you'll have to synthesize them out of PTC/NTC thermisistors
https://northcoastsynthesis.com/news/temperature-compensation-with-ntc-thermistors/

shieeeeet why is kicad putting the silk screen on the same side the traces are for tht components? is there any easy way to get the kicad to put the f.silk on the OTHER side from f.cu and rotate it correctly? basically i will be inserting the tht from the other side than were the traces are so i need the silk on that side

>>1854570
Thanks, I was wondering if that could be done.
Sounds like calculating the required resistor network is a pain though.

I wonder if it would also be feasible to thermally bond the transistor pair to a small heating element and then keep them at a constant temperature.
I know that high-accuracy crystal oscillators are often put in a temperature controlled oven, so it's just a matter of if it can be scaled down to a transistor pair on a pcb.

>>1854404
>fake alarm indicator light for a vehicle?

find an lm3909, a 1.5V cell and a bright red LED. with an alkaline D cell, it should work for over a year 24/7.

>>1854622
that sounds like even more of a pain desu
The NTC method is actually pretty simple. Calculate what the voltage will be at the relevant node (I'm assuming Vbe on one base of a diff pair) at 25C, then what it'll be at -10C, and then what it'll be at 40C.
Look up the datasheet for the NTC's you have on hand, and figure out their ppm. It should be 20,000-50,000ppm. Then design a 3-resistor network that gives the same outcome at -10C and 40C.

I got a dead IFM 24v dc power supply with a blown fuse behind the input terminal inside the chassis. It kinda looks like it was hidden inside the psu for a reason and not meant to be serviced. The psu was powering a relatively small dc motor, the wiring for it was done by a professional and it was in working condition for a couple of months.
What would be likely to cause this and should I even attempt at repairing this with my limited knowledge on electronics?

>>1854687
>What would be likely to cause this

everything dies eventually.

>should I even attempt at repairing this

yes, if you enjoy hopeless pursuits.

>>1854687
Not particularly, especially if it's an SMPS, the capacitors can give a nasty bite. Earned myself the big dummy award the other day taking apart a LED bulb and got bit.

>>1854534
pls atleast recommend some reading pls

>>1854704
>>1854705
Yeah I suppose I'll leave this be. I had a feeling that it's probably not coming back.
Thanks anyway.

>>1847774
I was given a Philco 665 from 1935-6ish. I've got the schematic, but I'm unsure how the speaker is supposed to hook up, someone cut the connector off. It uses push pull audio (If anyone has the time to teach a newbie how that works, I'd really appreciate that).

Side question, can you get audio out without the transformer that is supposed to be mounted on the speaker ( a Philco H-13).

>>1854568
not being able to easily nest conditional statements is real shit

>>1854798
Can you circle the part you're confused about on the schematic?

And yes, you absolutely need the output transformer.
Vacuum tubes have a high output impedance, while speakers are fairly low impedance. The transformer serves to match the tube's impedance to the speaker.
Without the transformer, the tubes wind up dissipating most of the power and little power is delivered to the speaker.

>>1854479
Tis-100 is good too. and the hexawhatever game too. They are not dumbed down what is dumbed down is the number of registers the the fact you don't deal with word and register sizes.(Assembly is so simple and reduced that I don't think you can dumb it down) But it's a very good way to get into assembly because those are technicalities. You need to learn how to make checks and loops and set things up and the game teaches you that.

>>1854801
I mean, that's just like how real assembly works.
It would be nice if you had a stack you could push temporary values onto though.

>>1854479
It's not too far from real assembly, although the predication scheme is fairly rare to see in real architectures. (predication meaning how to you can prefix an instruction with + or - to make it execute or not based on the comparison instructions)
I actually got about 90% of the way through implementing a real processor based on Shenzhen IO's before I got distracted by another project.

>>1854807
Exapunks was a lot of fun, probably my favorite so far.
The limited number of registers also wasn't quite such a headache in Exapunks, since you can use the file I/O to implement a stack, and you can do fork/join multitasking with ease.

>>1854803
Never mind, thanks for your help, since the transformer is missing I'd be pretty hard to hook it up.

>>1854818
You can probably get a replacement transformer fairly easily.
High quality output transformers are expensive, but you can get PA/Intercom transformers for less than $20
https://www.amazon.com/Commercial-Transformer-8Ohms-OSD-Audio/dp/B007TJNP5M/
They don't sound as great, but for a radio they'll be more than sufficient.

>>1854822
Does the numbering scheme for the old transformers still apply today, or would I have to find out what a 32-7078 is and find a modern equivlent?

>>1854813
Yes, but I mean the limtie dnumber of registers in relation to a real application. That's the only simplification I can see with these games (aside from the limited ammount of code and output forms)

>>1854826
You'd have to find a modern equivalent.
From what I can find about old philco transformers, it sounds like the 32-7078 has a 2kΩ impedance on the primary, so that's what you want to look for.

>>1854716
pls

>>1854828
Yeah, compared to modern processors it is pretty limited.
Still though, the number of registers isn't that far off from the 6502 or the 8086.

>>1854522
I know all about filtering.
But switching noise tends to get through all that, which is the main criticism of having a switching preregulator behind the linear section
>why have a linear power supply if its going to be noisy because of the switcher anyway
etc
all i got is potentially slowing down switching edges, low ESR caps obviously, and ferrite beads in series with the switcher output

Hey, im working on an asus memo pad 7 for a friend. They have asked me to attempt to recover some files from it. After some fooling with it i got it to show a red almost empty battery. I left it on the wall charger for 2 hours with no luck. I heard that usb ports on a desktop can do a "trickle charge" so i left it plugged in at work for 9 hours and still no luck. Im guessing the battery is dead, im skeptical about ordering one. Im worried that im going to get an old battery that is dead as well.
I was thinking about powering it with a bench power supply and just bluetoothing or using the usb port to transfer the files off. But the battery connector is a little strange looking, pic related. Can i power this tablet with a bench power supply? Thanks for any help you can provide in regards to this!

>>1855026
It depends on how danger cowboy you're feeling. On OSHA ranch, you'd replace the battery with an OEM approved replacement and of course properly dispose of the old one. At howdy tier you'd find the pinout of the battery and drive the board directly with the correct voltage. At yee-haw tier you'd snip the tabs off the old controller board and either drive it with the bench supply through the balancing board or you'd replace the cells with new cells. At full hey y'all tier you'd use your bench supply to charge the cells up to nominal then either finish the job on your bench supply or pop it back in the tablet to finish charging.

So I've seen online a lot of 3rd party Sony Unilink/Alpine AI-Net adapters for various purposes that all seem to use the same manufacture of connector. Does anyone know what that connector is called or where to just get the connector?

>>1855335
I'm torn between howdy and hey y'all. Think I'll hunt for the pin out and if I don't have any luck I'll get the whiskey out! Much obliged!

what dirt cheap kits do you guys recommend for a third worlder 29 yo beginner?
i already have experience in c and assembly from big computers but i want to play with smaller ones and have fun.

>>1855393
You can pretty easily suss the pinout by doing some basic probalyzing and sprinkling a bit of logic, EG seeing what pins are connected to shielding (ground) and what pins are bonded together/chonky (power).

>>1855396
well, what are you interested in? What do you want to do? What are your current goals as far as electronics are?

>>1855399
i don't know, i just wanted to fuck around with it. i don't have any projects in mind.

i'm depressed and wanted to try something new/exciting for my birthday which will be next week.

Are there any good places I can hire someone to help design simple circuits, or help make things in KiCad's simulator?

>>1855402
>something new/exciting
weed?

but electronics wise, since you mentioned c, try blinking LEDs with arduino. it is fun and perfect for just fucking around.

god I hate ltspice
is it really the best we can do

http://ww1.microchip.com/downloads/en/DeviceDoc/MIC550X.pdf

this thing comes with an enable pin that apparently delivers no current if it's "low".
I'm a bit paranoid but do I need a pull up resistor to keep it high as it can be left floating which would mean the Enable pin would be in an unkown state?
I am not sure but I think I have to connect a resistor in series to the supply voltage.

>>1855523
TinaTI?

>>1854841
Thanks

>>1855523
You do know that you have to set your own hotkeys to make it the best circuit editor and sim on the market right?

>>1855523
i guess it depends on what you used before.
i love ltspice and hate everything else since i learned ltspice first so i am biased. i hate other spices with passion. what do you hate about it?

>>1855523
oh, and also this:
>>1855670
i set my own and also learned the defaults.
and i only use very few of them and thats all i need:
G - ground
r - add resistor
c - add capacitor
l - add L
D - add diode
a - add element and search and select from the list
w - draw wire , immediately start drawing
space - fit the screen
ctrl-r - rotate element
ctrl-c copy element
ctrl-d run simulation
v - move element
ctrl-r rotate
ctrl-e mirror
T - add text
S - add directive

>>1855545
you can just tie EN directly to VIN, no need for a resistor. floating it will cause it to either pull down to gnd (shutoff) or float, enabling and disabling unpredictably, depending on the chip model.

>>1855693
thanks

>>1855685
I'm partial to the function keys
F2 - add element from list
F3 - add wire
F4 - label node
F6 - copy
F7 - move
F9 - undo
shift+F9 - redo

>>1855402
astable multivibrator, make flashing cop lights
atari punk square wave generator (they sound downright evil when they have a ground loop mixed in)
Or just buy a bag of LED's, burn them out 1 by 1 and appreciate the smells

>>1855841
i see. i really hate the function keys cause i am always sitting on the couch leaning back and my fingers are on the letters with the wrists firmly anchored on the the laptop's surface. so reaching for an fkey is a bit of a hassle.

every time I use ltspice it feels like a boomer is going to kick down my door and start ranting about participation trophies or something

>>1855916
it's training experience for your future job.
>implying I'll get a job after 2020
yes

>>1856135
>yes
not him, but where? i'd be surprised if the defense industry isn't in a global hiring freeze for the next 3 years. i'm sure telecom and consumer tech aren't much better off.

>>1856147
Mcdonalds.

>>1856147

machines dont incubate, so expect all the service employees to be replaced by robots: stock placers, sandwich makers, cashiers, sales associates, sliced bread cutters, mop jockeys, grocery cart wranglers, parking lot attendants, information kiosk gabbers, dressing-room item counter-uppers, etc.

if you start your own company, in 5 years you could buy out Elon just for fun.

>>1856204
>implying the industry giants aren't already doing that
ABB and similar companies can't be beaten.. When I graduate I'll just join the great unemployed mass of service workers and die in the climate war.

>>1856205
>tfw graduated in automation and robotics
Can't beat 'em join 'em

>>1856208
They need to hire you first men. I'm still receiving letters about cancelled internships..

>>1856211
First, man*

On the left is kicad silk screen, on the right is chink gerber preview from a fab house (pcbways) why the fuck is that curve upside down?

It's like that on all of the silks screen for chips that have that curve

>>1856271
I mean it's not the end of the world, the traces all look fine, but it looks ugly as fuck
Is it just gerber viewer error or will it look like that if i have it made?

>>1856282
>>1856282
>>1856282
>>1856282
>>1856282

>>1855843
Blow up old electrolytics, tons of fun.