/ohm/ - Electronics General: Workbench Edition

[Anonymous No.851753]

Previous thread:
>>843077

>I'm new to electronics, where do I get started?
There are several good books and YouTube channels that are commonly recommended for beginners and those wanting to learn more, many with advanced techniques. The best way to get involved in electronics is just to make stuff. Don't be afraid to get your hands dirty.

>Links to get started
http://pastebin.com/9UgLjyND

[Anonymous No.851755]

What are some common mistakes you could make when tinkering with electronics that could severely injure and/or kill you?

[Anonymous No.851761]

>>851755
https://www.youtube.com/watch?v=sW0a9d_vWoc

[Anonymous No.851762]

>>851755
Starting your DIY experience by opening your CRT TV.

[Anonymous No.851773]

My electronic workbench at home.

[Anonymous No.851790]

OP is a fag these pictures are the first results on images.google.ca for "Electronic workbench."

[Anonymous No.851837]

>>851753

Take a class, seriously. Messing around at home if you know nothing you may end up breaking stuff and getting electric shocks or starting fires because of short circuit and overheating.

[Anonymous No.851905]

So I am trying to make a gag item, which plays a sound file when the device is tilted.

I know that I need a tilt switch, but what should I use for decoding a small mp3, playing audio through one speaker, and power supply?

The only wiring I've ever done is experimenting with a breadboard and a radio kit.

[Anonymous No.851941]

>>851773
That's wonderful looking

[Anonymous No.851942]

>>851905
I think they make an Arduino board for that.

[Anonymous No.851945]

>>851762
>implying CRT's aren't practically free these days
>implying anyone would be disappointed if they fucked up an already non-functional CRT

I used to get CRT's for $5-15 at garage sales, desolder the bigger components (mostly the capacitors), clean em up, fix the mounts, and sell them on ebay for a profit.

[Anonymous No.851947]

>>851762
Scratch my last comment,
>>851945
I misread what you were replying to.

[Anonymous No.851951]

>>851905
https://www.youtube.com/watch?v=PRhG5cQL7O4

[Anonymous No.851953]

>>851905
http://www.pjrc.com/mp3/sta013.html

[Anonymous No.852166]

I use Labcenter Proteus design suite, for design and sim but it's buggy as hell specially on the simulation part, from the pastebin which one of these would you say it's the most similar one or in other case the one that's worth getting into.

NI Multisim
LTSpice
CircuitLab

[Swifts !WiNDUPyWhk No.852179]

>>852166
Well, I use Multisim, Multisim BLUE to be specific, since it's free.
It's arguably easiest to use since it has a large component library.
The issue with it and most simulation software is that things get slow once you add too much stuff.
Multisim for example slows down too much to be useful if you try to simulate 2 555 timers at once.

[Anonymous No.852182]

>>852179
Thats nice, but why did you feel the need to post with a trip?

[Anonymous No.852183]

Maybe I can do this but really wanna try it out after giving up.

I have an old non-working camera and want to use the sensor for a proyect. I've done some research but can't find anything about the needs to decode the information from the sensor and decode it to a mini lcd screen, so the question is: Is there a way to take the sensor and build (or buy) a PCB board to take the image off the sensor and send it to a screen?

I certainly don't have the right tools but want to take it as a learning expirence.

>Pic related is the sensor and the screen

[Anonymous No.852189]

>>852166
Just use LTSpice, it's free.

[Anonymous No.852200]

>>852183
In the unlikely chance you can find documentation on the sensor, you can talk to it with a FPGA or fast microcontroller to get the data out.

[Anonymous No.852205]

Quick question. I looked up how to make your own circuit board but I just can't be bothered, plus I dont have the tools necessary. What are some good websites or companies that allow you to send in a circuit design/schematic and have it made?

[Anonymous No.852305]

Here is mine

[Anonymous No.852411]

>>851753
What's a good way for a college student to organize his workbench? I'm in a dorm but it's a suite style so I have some room to play with.

[Anonymous No.852425]

>>852305
Impressive

[Anonymous No.852478]

This is a circuit I designed based off of an online source's info that pulsing an SCR with a large amount of current would turn it on faster. Would this circuit work and if so would it produce a noticeable difference in rise time?

btw, the CBANK is a capacitor bank charged to 75 Volts

[Anonymous No.852484]

Who here is an electrical engineering major?

[Anonymous No.852489]

I decided to try and find a method to measure the current flowing through an AC cable, I used a 60W light bulb as a load (0.3 amps) and I placed several toroids along the wire and measured the voltage with the scope just to find there isn't any noticeable change in the voltage. What am I doing wrong? Are the toroids? Or maybe I havent used enough turns?

The reason I'm doing this is because I want to install an electronic fuse to make a tesla coil, in case the current raises too much a relay should open avoiding further damage.
I was thinking about using an OP amp to do this. Is there a better way?

[Anonymous No.852521]

my workbench so far consists of a cheap ass fluke knockoff and a variable PSU built from a laptop power brick and a buck converter

gotta start somewhere, need to find me one of these fabled dumpster oscilloscopes

[Anonymous No.852524]

>>852489
Think about how the current flows. If you clamp around live and neutral the fields mostly cancel.

[Anonymous No.852533]

>>851755
Not unplugigng what you're working on. In my experience it takes some compent to spark in some new guys face before they're scared into never working on something without removing the mains.

[Anonymous No.852542]

>>852489
>electronic fuse
use a miniature circuit breaker, MCB.
like from an electrical panel?
like in your house?
costs what a couple of dollars?
what kind of current are we talking about?

[Anonymous No.852543]

>>852524
I already tried using a toroid just with one wire, I got this, around 10 mV in between all the noise, maybe I should try to use an OP amp (even though 10mV is a shitty signal to start with) with a low pass filter or add more turns. Any suggestions?

[Anonymous No.852544]

>>852489

WTF dude, you want several hundred turns on that coil. and, as the other dude said, you only probe one wire, not the 2 together coz they cancel.

[Anonymous No.852545]

>>852542
Yeah, a circuit breaker would be a better option, I was just trying to improvise something with the things I already had.
I plan to build a tesla coild that doesn't exceeds 500 to 1kW, depending on the materials I have, so the current limit would be around 2 to 4 amps (250V)

[Anonymous No.852546]

>>852478
Your schematic gave me cancer, hope you're happy.

[Anonymous No.852547]

>>852543
if all you see is noise on the scope, all you're going to see out of the op amp is noise, too.

[Anonymous No.852548]

> if all you see is noise on the scope, all you're going to see out of the op amp is noise, too.

unless he uses an instrumentation amplifier which removes the common-mode noise.

[Anonymous No.852557]

>>852484
>>852484
please respond

[Anonymous No.852562]

>>851755
not discharging capacitors
shorting shit
leaving something plugged in
not keeping tabs on your hot soldering iron
HVAC

[Anonymous No.852563]

>>852557
I used to be one.

[Anonymous No.852564]

>>852563
did you drop out or change majors?

[Anonymous No.852578]

Mine, mostly for small repairs and some arduino stuff, there is a fluke 115 on one of the drawers, i'm still missing a good soldering station, i have to make do with a cheap ass chinese station and soldering gun.

[Anonymous No.852579]

>>852578
sorry for the pic, stupid android phones...

[Anonymous No.852583]

>>852557
I did a computer engineering degree. My courses were the same as EE until the last year or so.

[Anonymous No.852609]

>>852533
I got shocked by 170 volts at .5 ma a few days ago but I'm still going

[Anonymous No.852634]

>>852564
No.

[Anonymous No.852644]

>>852557
I'm a History major.

Electronics is a hobby, because I am really bad at Math. Like, bad enough to where I retook Calc II 3 times and the professor just told me to stop going to office hours bad.

[Anonymous No.852655]

>>852543
take a look at hall effect sensors, they have the ability to sense both AC and DC current from the same setup and are much easier to trigger something with a comparator since the output is just DC.

[Anonymous No.852673]

>>852644

damn son. At least you stuck with it, and it's neat that you stick with a science/math related hobby.

[Anonymous No.852681]

>>852609
I touched a oil burning furnace igniter wired to a test whip plugged into the wall. Someone left it plugged in, my turn to clean the tool room.
> sticker on side "you touch you fry"
> stuck to hand, came unplugged when i pulled away
> could literally feel it coming out of my feet
> teeth hurt afterwards
Played with the thing every day before that, i couldn't even touch it after. Even if i saw it was unplugged

[Anonymous No.852741]

>>852489
AC Line Current Detector

This circuit will detect AC line currents of about 250 mA or more without making any electrical connections to the line. Current is detected by passing one of the AC lines through an inductive pickup (L1) made with a 1 inch diameter U-bolt wound with 800 turns of #30 - #35 magnet wire. The pickup could be made from other iron type rings or transformer cores that allows enough space to pass one of the AC lines through the center. Only one of the current carrying lines, either the line or the neutral should be put through the center of the pickup to avoid the fields cancelling. I tested the circuit using a 2 wire extension cord which I had separated the twin wires a small distance with an exacto knife to allow the U-bolt to encircle only one wire.
The magnetic pickup (U-bolt) produces about 4 millivolts peak for a AC line current of 250 mA, or AC load of around 30 watts. The signal from the pickup is raised about 200 times at the output of the op-amp pin 1 which is then peak detected by the capacitor and diode connected to pin 1. The second op-amp is used as a comparator which detects a voltage rise greater than the diode drop. The minimum signal needed to cause the comparator stage output to switch positive is around 800 mV peak which corresponds to about a 30 watt load on the AC line. The output 1458 op-amp will only swing within a couple volts of ground so a voltage divider (1K/470) is used to reduce the no-signal voltage to about 0.7 volts. An additional diode is added in series with the transistor base to ensure it turns off when the op-amp voltage is 2 volts. You may get a little bit of relay chatter if the AC load is close to the switching point so a larger load of 50 watts or more is recommended. The sensitivity could be increased by adding more turns to the pickup.

[Anonymous No.852746]

>>852489
I spent a 30 minutes finding this for you. :)
http://www.bowdenshobbycircuits.info/page8.htm#aclatch.gif

AC Line Current Detector

This circuit will detect AC line currents of about 250 mA or more without making any electrical connections to the line. Current is detected by passing one of the AC lines through an inductive pickup (L1) made with a 1 inch diameter U-bolt wound with 800 turns of #30 - #35 magnet wire. The pickup could be made from other iron type rings or transformer cores that allows enough space to pass one of the AC lines through the center. Only one of the current carrying lines, either the line or the neutral should be put through the center of the pickup to avoid the fields cancelling. I tested the circuit using a 2 wire extension cord which I had separated the twin wires a small distance with an exacto knife to allow the U-bolt to encircle only one wire.
The magnetic pickup (U-bolt) produces about 4 millivolts peak for a AC line current of 250 mA, or AC load of around 30 watts. The signal from the pickup is raised about 200 times at the output of the op-amp pin 1 which is then peak detected by the capacitor and diode connected to pin 1. The second op-amp is used as a comparator which detects a voltage rise greater than the diode drop. The minimum signal needed to cause the comparator stage output to switch positive is around 800 mV peak which corresponds to about a 30 watt load on the AC line. The output 1458 op-amp will only swing within a couple volts of ground so a voltage divider (1K/470) is used to reduce the no-signal voltage to about 0.7 volts. An additional diode is added in series with the transistor base to ensure it turns off when the op-amp voltage is 2 volts. You may get a little bit of relay chatter if the AC load is close to the switching point so a larger load of 50 watts or more is recommended. The sensitivity could be increased by adding more turns to the pickup.

[Anonymous No.852805]

Question: I recently a 3-input/2-output passive audio matrix/switcher. It works great, except when I plug the computer in. Whenever my PC's output is connected to the switcher, I get a high-pitched hum/whine, which I assume is a ground loop. But the thing is, it's ONLY when the computer's plugged in. I got tired of hearing it, so I took it out temporarily, and again it works perfectly fine. Right now, my TV's headphone output is connected to the switcher's 3.5mm input (which was going to be the PC in). I'm wondering why this is.

If it matters, 1 input and both outputs are 3.5mm jacks, and the remaining two inputs are RCA.

Sorry if this doesn't 100% make sense, I'm starting to get a bit tired, it's 2am and I've been up most of the day.

Any help would be appreciated, though.

[Anonymous No.852809]

>>851755
'Trust' or 'faith' when working with mains.
Seems stupid, when I check every piece of wire, if it's cold or not and checking the 'voltage checker' after every 'no voltage on line'.
A few years ago I did a whole new wiring in my apartement. All fuses and switches were 'off' and I startet checking if cold and then cutting down the wires. I stopped after a while because of sparks and ozone smell.
Two things I learned: cables coming out of the fuse box could be wired 'before' the switches and voltage checkers can also be broken.

[Anonymous No.852875]

>>852746
Thank you so much! I'm going to try it now, I guess I could fix the chatter by latching the circuit so when the relay disconnects once everything shuts down, keeping the relay open.

I'll also try >>852655, I've seen them inserted inside a gap cut in a toroid, this could work too.

[Anonymous No.852911]

>>852805

this question was already asked and answered. it's odd you copied the exact same text, including the part where you're tired. that's fucking lazy.

[Anonymous No.853010]

>>853009
>>853009
>>853009

I posted this in the wrong thread. Can someone answer?

[Anonymous No.853017]

>>853010
Presumably it's a current source for the transistor that's acting as an amplifier.

[Anonymous No.853027]

Where's Rave-Kart Russel?

I need to indulge in his glorious insanity.

[Anonymous No.853130]

>>853027
I'm still working on turning a NES zapper and computer monitor into an analog musical instrument.

https://www.youtube.com/watch?v=02f_izRLHr4

The circuit generates a VGA signal with just a schmitt-nand trigger and binary counter IC, then gets the X and Y from the light gun as analog voltages by sample-and-holding some sawtooths that sync up to the Hsync and Vsync pulses. These voltages go to voltage controlled oscillators to produce sound. The sound is used to generate the RGB VGA inputs, so the monitor shows sound responsive patterns that feed back into the audio circuits through the light gun.

[Anonymous No.853215]

>>853130

reminds me of Boyd Rice. i can listen to that shit for hours.
https://www.youtube.com/watch?v=I4UpI1UMO7E

[Anonymous No.853257]

>>853130
that's goddam beautiful

[Anonymous No.853285]

I'm trying to make a reliable square wave generator but google just shows operational amplifiers and other circuits which are not easily adjustable. It doesn't needs to go into the negative range. All I want is to adjust the duty cycle and the frequency, from 0Hz (ideally) to at least 1Mhz. I tried with a 555 but their maximum frequency is about 200-300kHz if I'm not wrong. I would try the CMOS 555, but I haven't found any circuit that allows me to use them properly. The best thing I could find is this circuit, but the duty cycle range depends on the value of the frequency potentiometer, what makes the circuit very buggy and unreliable.

Can someone point me what IC or circuit should I use?

[Anonymous No.853286]

I'm trying to make a reliable square wave generator but google just shows operational amplifiers and other circuits which are not easily adjustable. It doesn't needs to go down into the negative range. All I want is to adjust the duty cycle and the frequency, from 0Hz (ideally) to at least 1Mhz. I tried with a 555 but their maximum frequency is about 200-300kHz if I'm not wrong. I would try the CMOS 555, but I haven't found any circuit that allows me to use them properly. The best thing I could find is this circuit, but the duty cycle range depends on the value of the frequency potentiometer, what makes the circuit very buggy and unreliable.

Can someone point me what IC or circuit should I use?

[Anonymous No.853293]

>>853130
Which is kinda cool, but couldn't you fit the entire thing into a Wiimote, and then have it work with anything and everything that looks like a wensor bar, up to and including a pair of candles?

And when there's nothing for it to see, it could be a theremin.

[Anonymous No.853303]

>>853286
get a microcontroller and connect a potentiometer to an analog input.

[Anonymous No.853308]

>>853293
A WIImote uses an IR camera to figure out where the sensor bar is. Using that technology would be a very different project: Microcontroller to read camera data, generate waveforms in code, then output to a DAC.

I wanted a change of pace from microcontroller based projects so I decided to do something with only analog hardware like people did in the early days of electronic music.

Using light gun technology also means I get a lot of exciting unexpected audio and visual effects. There's a feedback loop: Audio effects the video output, which effects the light gun output, which effects the audio.

[Anonymous No.853310]

>>853308

[Anonymous No.853322]

Interfacing the 10bit ADC of the ATMEGA328P (arduino programmed) with multiplexed 7SEGs to make a voltmeter. Researching on how to increase the accuracy of the ADC by having a more stable Vref

[Anonymous No.853373]

>>853310

[Anonymous No.853384]

Trying to build an atari punk console...easy shit I know, but I cant figure this out

Had this exact circuit working, brought it to a party, now it doesnt work. All the components are in. connections on the breadboard are fine(to my knowledge). The speaker clicks when I turn it one, battery is good. Any ideas?

[Anonymous No.853438]

>>853322
how do you know your ADC isn't correct and your DMM is full of shit? it's not even a fluke!

[Anonymous No.853444]

>>853303
I don't know about a single microcontroller which can be programmed to output a 1MHz signal without problems, I just know how to work with AVR uCs, but I'm terrible when it comes to optimize programs like those. I've seen attiny85's used for that, but they only reach a few hundred kHz.

[Anonymous No.853456]

>>853384
Replace the chips, sounds like one of them could've fried, maybe the second one, since the output impedance might be too low, if one of the chips gets hot during operation you'll know you've done something wrong.
Also check again for detached cables and so on...

[Anonymous No.853465]

>>853444
try making an oscillator with discrete components

[Anonymous No.853493]

>>853444
>I don't know
yeah, it's apparent you don't know anything.

[Anonymous No.853499]

>>853286
if all you need is a square wave why not look at CPLDs? you can either implement a basic ADC and use a pot to control the frequency, or if accuracy is important you could use a mechanical encoder and step it at whatever resolution you wish, most of the CPLD's from lattice have built in clock generators that run off an external oscillator for very high accuracy, you also wont loose precision as the frequency go's up as you do using a uC since your divisor logic can be running at many hundreds of Mhz.

additionally, creating other types of waveforms is a lot easier since you can then do very very fast PWM(if you use one leg of a differential output on a machxo2 it can be driven up to 1.2Ghz) and filter that into an analog signal or output to a resistor network.

[Anonymous No.853672]

Is there an easy way to control individual bulbs in a fixture? Like I'd there something I could put in between a bulb and the fixture to control just that bulb?

The overhead lights in my apartment just are 2 staight tube CFLs and I wanted one blacklight tube and one regular so I could control them independently

[Anonymous No.853706]

So some chink on alieexpress sent me an NO sensor switch when I ordered an NO+NC sensor switch. How can I add an NC like behavior using the fewest parts possible?

[Anonymous No.853707]

>>853672
You could wire the anodes together then have each cathode going to a switch if they're polarized.

[Anonymous No.853709]

>>853672

there's this, a cheap mechanical solution, and a better looking but more expensive electronic remote version, such as X-10 light bulb modules.

[Anonymous No.853710]

>>853706

without more info, all i can suggest is (1) an inverter, or (2) an inverter powering a tiny reed relay.

[Anonymous No.853720]

>>851773
Nice.
Makes me realise how much simpler my life would be if i were to acquire some shelves.

[Anonymous No.853882]

>>853444
Anything with hardware PWM, running at a few tens of MHz will very easily do that for you.

[Anonymous No.853887]

Sup /diy/, I'm a programmer who doesn't know dick about electronics. I recently became interested in learning about it all when a project idea I had would require it.

What are some basic projects that would help me learn the application of resistors, capacitors, inductors etc? I've looked through the pastebin, and found a lot of the YouTube channels have some pretty advanced shit with guys using hella pricey equipment.

As some of you may know, in programming we have classic programs to learn/improve/display understanding of programming knowledge, like fizzbuzz, making a scientific calculator, or whatever. Are there projects like this in electronics I could give a whirl?

[Anonymous No.853890]

>>853887
555 astable multivibrator circuit is the oldschool hello world of electronics. You should give it a try instead of going straight to microcontrollers and skipping the basics. It can blink an LED or produce a tone in a small microphone.

> in programming we have classic programs to learn/improve/display understanding of programming knowledge

You can take the same approach with electronics. Once you've got the simple 555 circuit working try adding things:
- make the frequency variable with a potentiometer
- Connect it to a power transistor to drive a larger light or speaker
- Connect it to a binary counter chip like the 4040; or other logic chips.
- Produce a nice sawtooth wave by adding a cap, resistor, and transistor
- use it to drive a small transformer and charge up a high voltage capacitor

[Anonymous No.853895]

>>853887
Make: Electronics by platt is a good starter book and has some projects for basic components.
As for equipment just browse craigslist listings, yard sales for cheap but quality brands.

>Are there projects like this in electronics I could give a whirl?
555 timers haz em

[Anonymous No.853984]

is downloading a circuit simulator program a good way to learn about electronics?

[Anonymous No.853992]

>>853984
You can learn some things from a simulator, but you won't see a lot of real world problems: Noisy power supplies, resistors and caps only being within 5% of specified value, capacitor leakage current, batteries having an internal resistance, the need for decoupling caps etc. Some simpler simulators will even do things like make every op-amp completely perfect and every digital component have instantaneous response time. With no prior electronics experience you won't pick up on things missing from the simulation.

[Anonymous No.854140]

How to get into hobby electromagnetics?

[Anonymous No.854142]

>>853984

absolutely not. simulators are super finicky, and frustrating to use. you'll find yourself asking why the simulated circuit works completely different from the real circuit, and start to doubt your own reality. sure, it's nice to have a ton of components at your fingertips and a simulated breadboard, but it's only for advanced users who can tell when the simulator is spitting out bullshit.

instead, you wanna find projects like in >>852746 and read the description to see what each section does.

[Anonymous No.854143]

>>854140
>acquire copper
>melt said copper into ingots
>acquire ferris material
>grind said ferris material into a powder
>produce copper wire/sheet
>coat wire/sheet in enamal
>use compression mold to shape I or E type core
>wrap core with wire/sheet
>apply electrons

Honestly electromagnetics are very /diy/ friendly since buying them is fuckin expensive, is a lot easier to get shit prototyped and made just with some basic tools than it is to find some zipper head willing to sell you what you need in one offs.

[Anonymous No.854144]

>How to get into hobby electromagnetics?

buy 10,000 ft of magnet wire and start winding it around everything you see. apply electricity and note results in leather handbook.
build orgasmatron for hand-free orgasms.

[Anonymous No.854147]

>>854143
I don't have the ability to do any of that stuff tho Lol


>>854144
Well this sounds fun

[Anonymous No.854154]

>>854143
>Ferris
Were you dropped on your head at some point

[Anonymous No.854217]

>>852484
I've been working as an EE for almost 10 years now.

[Anonymous No.854225]

>>852484
I am

[Anonymous No.854610]

>>854217
what's your highest level of education?

[Anonymous No.854852]

hey /oh/m I'm just a poor white boy trying to get an education and I need switching regulators for a project involving rf transmitters intended to be installed as long term data gathering/security infrastructure, so the battery needs to last(something on par with smoke detectors)

Now I don't have access to or the money to buy any switching regulators but I was wondering about the viability of taking something like a 7805(of which I have plenty) and hooking the output to a 5v super cap (I have a few). That input to the voltage regulator would be switched on by a transistor when the PIC MCU woke up, while the regulator was off the sleeping PIC would draw its current from the super cap which would get a "snort" of power everytime the regulator ran.

Anybody know the viability of this or ever hear of it being done before?

[Anonymous No.854868]

Is it possible to build a night vision device with the raspberry pi that does not need an infrared "lamp"?

I'm talking about image intensification on the software side. I guess the main problem would be amplifying the camera's signal and maximizing the amount of infrared photons that gets to it.

[Anonymous No.854895]

>>851753

I'm a complete beginner. Thank you for the links.

[Anonymous No.854910]

>slam mouse
>8 through hole solder joints break
is it normal for small solder joints to break easily?

[Anonymous No.854912]

Hey /ohm/. What should I be looking for when buying my first soldering iron? Which wattage is ideal? Are there any specific "go-to" models?

[Anonymous No.854922]

>>852305
damn...

[Anonymous No.854932]

>>854868
No, unless you have a special sensor. Normal camera's signal will do nothing for you, amplified or not.

[Anonymous No.854942]

Is there a go-to brand for multimeters? I'm looking for one which includes a capacitance meter, preferably under $30, and there's dozens of models available on amazon.

You guys probably get a ton of these, and I apologize in advance.

[Anonymous No.854944]

Not quite electronics nor workbench, but I installed some new lights in the basement today, running on 100 % off-grid solar power.

Which means that I probably have the biggest battery powered lamp on 4chan, since they'll produce 3000 lumens, 24/7, for 25 days on battery power only.

>>854852
You'll have to do the calculations. I would bet that you'd be better off with some ultra low quiescent current draw linear regulator than a 7805 in any configuration. Pulsing large amounts of current through a linear reg is not usually a recipe for efficiency.

[Anonymous No.854980]

>>854942

YOUTUBE :

" EEVBLOG MULTIMETERS "

[Anonymous No.855060]

> Hey /ohm/. What should I be looking for when buying my first soldering iron? Which wattage is ideal? Are there any specific "go-to" models?

Weller. 25W for electronics (PCBs), or 40W for wiring. cost is around $30-$40. you wanna get the type in the pic, with the iron-coated tip, not the $20 Weller they sell at Home Depot with a nickel-plated copper tip.

[Anonymous No.855062]

> Hey /ohm/. What should I be looking for when buying my first soldering iron? Which wattage is ideal? Are there any specific "go-to" models?

Weller. 25W for electronics (PCBs), or 40W for wiring. cost is around $30-$40. you wanna get the type in the pic, with the iron-coated tip, not the $20 Weller they sell at Home Depot with a nickel-plated copper tip.

[Anonymous No.855138]

>>854910
Improperly designed and manufactured single-sided boards can have pretty fragile solder joints.
Even then, if your ragequit broke 8 solder joint... Is the rest of the mouse still ok?

[Anonymous No.855150]

>>854610
4chan

[Anonymous No.855168]

Coiling a Tesla coil secondary, 34 AWG.
SUICIDAL MODE: No motor

[Swifts !WiNDUPyWhk No.855173]

>>855062
If it's Weller and it's Red, don't buy.
They're not exactly bad, but they're far from being good value for money, since they're mostly re-brands.

Nothing beats a good weller station though.

[Anonymous No.855176]

>>855173
>Nothing beats a good weller station though.

I use one of those at work about 95% of the time. This would be the next used iron after that. If you want fast heat and lots of it these are great.

[Anonymous No.855344]

I'm looking for recommendations on speakers for DIY use if anyone has any experience with them. I've never really worked with audio equipment myself though. I'm trying to find some cheap small speakers, like desktop computer size, that I can take out of the housing (or that have no housing) and mount internally in a DIY arcade cabinet I'm making. The only reason I'm asking is because I'm not sure if I can just pick up any cheap speaker set from Best Buy or Microcenter and get them out of their house easily or without damaging them, and even then if they'll be easy to mount. Anyone done anything similar?

While I'm on the topic, I'm not really very knowledgeable about electrical interference in audio, do I need to worry about that if I'm running the cables near a running CRT?

[Anonymous No.855424]

>>855168
You mad man we need laws to stop crazies like you

[Anonymous No.855442]

>>855344
If you just need speakers, buy bare speakers or salvage them. If you also need the amp, you shouldn't have any problem cannibalising PC speakers.

Interference is more of an issue for the line-level signal between the PC and the amp; that might need to use a screened cable. The connection between the amp and the speakers shouldn't be an issue.

[Anonymous No.855452]

>>854932
And what kind of special sensor would this be?

[Anonymous No.855508]

>>855452
flir sensor

[Anonymous No.855510]

>>855452

[Anonymous No.855534]

>>855173

except for a good Hakko station

[Anonymous No.855535]

>>852484
I just started my EE degree. I have a music degree already.

[Anonymous No.855539]

>>855062
Hakko is good

[Anonymous No.855587]

Kinda weird question, asking here because I don't know how to phrase it for Google:

I made a simple flasher circuit with a PUT and a capacitor, so when the capacitor voltage exceeds a set threshold it lights up the LED until the voltage goes below it. I'm wondering why the capacitor goes a little above the threshold voltage instead of instantly starting to discharge, and conversely, why it discharges more than just barely below the threshold voltage when lighting the LED. Is there a simple answer to this, or is this one of the trial-and-error things where it kinda arbitrarily works out that way? Thanks.

[Anonymous No.855589]

I found an Elenco 5-40 watt soldering station being sold for $15 yesterday near my house, should I go back and buy it if it's still there or is it a junk station?

[Anonymous No.855590]

>>855587
LEDs have an I/V curve - they aren't so binary

[Anonymous No.855593]

>>855590
I'm an idiot, so could you explain how that affects the charge/discharge of the capacitor? I figured the LED was more-or-less incidental (though the completed circuit's supposed to have a "soft" flashing), and was focusing on the PUT and capacitor.

[Anonymous No.855612]

>>855589
Too late son, I already bought.

[Anonymous No.855628]

Anyone have any insight on turning this laptop panel into a desktop monitor?

I know there are kits but I'm unsure of what I'm working with and how to start

Pic related is the 1920x1200 panel I am looking to recycle

Thank you.

[Anonymous No.855636]

>>855587
Why... Because the PUT is specifically made to behave that way. It wouldn't oscillate in your circuit if the turn-off point wasn't lower than the turn-on point.
If you can't find a decent explanation about PUT's operation, read about SCRs. Their latching mechanism is similar and you can build a comparable (not by simply substituting the active component, though) oscillator using them.

[Anonymous No.855638]

I am trying to use a tp4056 li-ion charging board like
http://www.newegg.com/Product/Product.aspx?Item=9SIA76H2GT0349&nm_mc=KNC-GoogleMKP-PC&cm_mmc=KNC-GoogleMKP-PC-_-pla-_-Eco+Gadgets-_-9SIA76H2GT0349&gclid=CMjC3YiTmccCFQktaQodrisKTQ&gclsrc=aw.ds

the problem is, due to the way my circuit is designed I need reverse polarity protection.

This tp4056 changes the charging current based on the voltage coming back from the battery.

Would putting a protection diode in-between the charging board and the battery fuck with the voltage sensing capability of the board? I know that diodes inherently have some kind of resistance, which would lower the voltage coming back from the battery.

[Anonymous No.855640]

>>855628
last time I checked, some ebay sellers that sell these lcd kits asked for the part number of your display, and would find the right board just for your lcd.

I don't have it bookmarked so your search is as good as mine

[Anonymous No.855742]

>>855593
Do you have a circuit diagram?

[Anonymous No.855745]

>>855628
Depends on of the panel is display port. That resolution would indicate that it is DP. There is a checkoslovakian guy who makes boards for 100$. But his design and board layout is retarded. Like he wired the ribbon connector upside down. I accidentally installed mine and found out the hard way that he's retarded. (The insertion tab with the insertion alignment mark should be visible from the top)

[Anonymous No.855746]

I'm building a battery powered sound box to play nature sounds and need an audio amplifier.

Being an idiot, I can't work out the power consumption of these things. They always state the output audio signal power (eg, a 20w amp), but I have no idea how that links to the draw on the power supply.

Can a non-idiot enlighten me on where to find the power requirements of, say, this one?https://www.adafruit.com/products/987

[Anonymous No.855814]

what's a good online arduino tutorial

[Anonymous No.855819]

So I got 5 meters of LED lights that can be controlled via remote control. It didn't come with a power supply, so I bought one at The Source. I've found that when I turn the brightness up too high, it starts flashing. I can't tell if this is just a function of the lights (because they do have a flash button) or if the power supply is not strong enough. It is only 0.3A, which might be a little low, but I don't know. How do I go about diagnosing this with a multimeter?

[Anonymous No.855826]

Just finished drilling a 150x200mm home made PCB for a AC > DC power supply.
It will have a +12V & -12V rail capable of supplying 2.5A each or 5A for just one, This will be dedicated to supplying a high current device on its own. There is also a low power +12V & 5V for Auxiliary components like relays, ICs etc.

[Anonymous No.855828]

>>855819
I can't estimate how much current 5 meters of LEDs will draw without knowing how many there are per meter.
But I can tell you straight away 300mA will not be enough for it, you will more likely be looking at a couple of amps.

[Anonymous No.855832]

>>855828
Super cool, I'll return it and get a better one. Thanks.

[Anonymous No.855886]

>>855636
OK, I read around a little and what I seem to find is that current passes through the PUT cathode when the anode voltage is a little higher than the gate voltage, and cuts off again when the anode voltage falls below the "valley point." If that's right, that explains my question.

Nothing seems to explain what determines the "valley point," though.

[Anonymous No.855913]

>>854852
any reason to use a PIC? you can get some pretty crazy low power modes on silicon labs EFM32 devices, I'm pretty sure they have quad SPI flash support so you could store some silly amounts of data long term.

pic related, I don't recall how long but it can run from that coin cell for a stupidly long time.

[Anonymous No.855920]

>>855826

[Anonymous No.855921]

>>854912
There needs to be a sticky for this, fuck wattage, get a temp controlled station, the lower the heating element mass the better for PCB and small work it will be, for connectors and large mass things you can't go wrong with a nip nog ching chong plumbers iron, just keep it maintained.

As for brands, as others have said Weller is pretty sic, you can buy kits to use there super high end tips($40-60 each) without paying out the ass for a station($1,600), just search for "weller rt diy".

[Anonymous No.855939]

>>852583
I'm currently studying CE, and this webm is very relevant to my interests since I'm about to build a theremin.

I've got a question: I need some variable capacitors for oscillators in the theremin, and the 1~60pF caps are out of stock at Digikey. If I replace them with a different capacitance range (like 1~70pF or 4~65pF), what's the worst that can happen?

[Anonymous No.855953]

>>855939
There won't be any problems, you'll just have a slightly different range of frequencies out of oscillator. The 1-70pF will be able to go to a slightly lower frequency. You could turn it into a 1-60pF cap by putting another capacitor in series with it or get the same oscillation range by adjusting another component (resistor or inductor); but I wouldn't even bother.

[Anonymous No.855963]

>>852305
Is this your YouTube account ?
https://m.youtube.com/#/user/Twistx77

[Anonymous No.855980]

My workbench ...

lots of space, need to get more testequipment

would love to have a old tube tester, but live in EUROPE and postage to here from the states is almost twice as much as the actual ebay price

FML

[Anonymous No.856089]

>>853890
>this
And go up to larger projects. Learn how to use decimal counters and op amps, make yourself a simple voltmeter with a 7447 to drive the 7 segment LED. We did this in my beginner digital class

[Anonymous No.856102]

Should I buy an arduino to learn about electronics?

[Anonymous No.856111]

>>856102
Not for your first projects. That's kind of like buying a calculator before you can to simple arithmetic. A microcontroller makes blinking an LED so easy it's hard for some people to put in the effort to learn how to build a simple oscillator from scratch, but those are the kind of skills you need if you ever want to use your Arduino for something other than following tutorials.

[Anonymous No.856117]

>>855886
The valley point is determined by the PUT construction, temperature, supply voltage and the gate resistor size.
The gate resistor has an effect, because it shunts a part of the internal current required to latch the device.
The datasheet specifies the effects of many parameters.

>>855913
Not him, but at smoke detector current consumption levels (ten microamps or more) the sleep modes of PICs are totally sufficient. It's the other stuff and the run mode functionality which determines the average current drain.

[Anonymous No.856147]

>>855920
would you learn more form designing, researching and building it yourself or simply modding an ATX power supply to meet your needs?

I have modded a ATX supplies in the past and while good it does not beat a supply designed to meet specific design goals, primarily size constraints and a high current -12V rail (most ATX supplies will only give you a few hundred mA).

[Anonymous No.856148]

>>855963
I do have a youtube account with some of my work but this is not it :)

[Anonymous No.856152]

>>856102
If you know how to program, an Arduino is useful for driving other components.

[Anonymous No.856153]

>>856102
no, Just no. Start off buy buying a small electronics kit with resistors, transistors, capacitors, LEDs etc in it and begin by doing a few little projects, maybe buy a book on basic electronics and watch a few youtube videos to help you understand. My very first project was just lighting up a LED with a transistor and a switch.

Once you have the basics understood then consider using a arduino to do things but if you want to know more about electronics always try and do something with electronic components first and then a microcontroller later on.

[Anonymous No.856184]

>>856111
Not that guy, but I'm an EE student that never did much hobby stuff. Always wanted to just never had money or space to. You've given me a good idea for a first project though. Instead of those basic "turn on this led with a 100 ohm resistor and a 9V" I think I'll make an RC oscillator and try to get it to blink the LED.

[Anonymous No.856209]

>>856111
>>856153
Any books or YouTube videos you'd reccomend?

[Anonymous No.856226]

>>856209

http://pastebin.com/9UgLjyND
This link is your friend and contains even more links to electronic goodness.

[Anonymous No.856243]

I got an old pinball machine from 1991 and now I'm trying to get it working again.
I came across some fuses with 3/8 ampere slow blow and 3/4 ampere fast blow
what does it mean? when does the fuse blow?

[Anonymous No.856250]

>>856243
For a fuse to blow, you need to heat the fuse wire enough for it to melt. This takes some time. "Slow" and "fast" mean just what one would expect, slow fuses taking more time to melt. The time is also highly dependent on overload and with some overloads "slow" fuses are actually faster.
Pic related, blow time vs. current curves for 5x20mm slow fuses.

[Anonymous No.856252]

>>856250
Sorry, I meant the values 3/8 and 3/4
they confuse me. Does the fuse blow at 3 or 8 Amps?
But thanks for your answer, regardless.

[Anonymous No.856254]

>>856252
3/8 = 0.375
3/4 = 0.75

[Anonymous No.856256]

>>856254
Ahhhh, alright so it's actually a division.
Thank you very much for clearing that up

[Anonymous No.856258]

>>856250
Why is time not the bottom axis on that graph

[Anonymous No.856273]

>>856258
To confuse you.

[Anonymous No.856495]

>>856258
Because it's the dependent variable, not the independent variable.

[Anonymous No.856508]

How do I generate a random signal without resorting to a microcontroller? I want to make an led flicker and I feel like an arduino is way overkill

[Anonymous No.856540]

>>856508
Do you actually need something that's random (takes advantage of the quantum electrodynamic effects), or is this just for a prop where it's okay to use a pattern, but it has to be complicated enough to look random to a casual observer.

[Anonymous No.856565]

>>856540
Just some pseudo random looking pattern would suffice. Thing is I will have a few of them, so the more random it is the better so the pattern doesn't become obvious when you see it side by side with the others. Basically think of those flickering candle lights

[Anonymous No.856617]

For some reason I cannot find any SMD resistors of 0805 in on mouser. Is something like 0402 okay?

[Anonymous No.856634]

>>856617
There's a big difference if you've never worked with 0402s before. But there's no way Mouser doesn't carry 0805s, you're doing something wrong.

[Anonymous No.856635]

>>856565
The 74hc4040 is a binary counter with an internal oscillator. Combining its outputs together a few logic gates (AND, OR, etc) should make sufficiently random looking LED blinks.

The helmet in front here was created with a 74HC4040. Each LED is the AND of only two different binary outputs, so their pattern is noticeable if you pay attention.

https://www.youtube.com/watch?v=zgXfAWVDjJo

[Anonymous No.856660]

Ive built this same exact circuit a few months ago but now it refuses to work. So could someone please try to build this circuit and post a pic of it properly made. I checked each individual component and tested each individual portion of the circuit and the only thing i can think is that theres something wrong with the transistor. Uses a 6v power supply btw and thanks

[Anonymous No.856672]

>>856660
what is it supposed to do?

[Anonymous No.856674]

>>856672
If the base of the transistor is more than 0.7 volts then the LED lights up.
>>856660
My advice, this circuit is really simple, so just rebuild it. If you rebuild it and it works, then you know one of the components broke.

[Anonymous No.856677]

>>856565
Afaik at least some of those flickering lights use Christmas card ICs. You know, those annoying noise makers.
A well-known digital way of producing noise-like signal would be an LFSR.
https://en.wikipedia.org/wiki/Linear_feedback_shift_register
Those are available as complete ICs as well, but they can be difficult to find.
Then there are analog methods like amplifying amplifier/resistor noise and amplifying zener diode noise. Pic related.

I'd use a small microcontroller, though.

[Anonymous No.856678]

>>856672
LED lights up when it's dark.
IIRC it blinks (in darkness) if you direct the LED to the LDR.

[Anonymous No.856685]

anyone here ever used icircuit

[Anonymous No.856699]

>>856565
i've used a circuit like this (input from a 555 timer and output to a opto-isolated triac) to make a box that "randomly" flickers christmas light strings. flicker speed controlled by 555.

http://saroselectronics.com/digital-noise-generator/

[Anonymous No.856737]

I want to attach a camera module to a raspberry pi and have it display what the camera sees on the LCD screen.

Will there be any noticeable latency between what the camera sees and what is displayed on the screen?

If so, will using something with a little more processing power like a Beaglebone Black help?

[Anonymous No.856740]

>>856737
Crazy and sort of pointless idea, but would it be possible to use 2 cameras to send pictures to the Raspberry Pi make a stereoscopic image then show that image on the LCD, which is placed inside a Google Cardboard-like contraption?

https://www.google.com/get/cardboard/

I suppose you can use something like this for night vision or really ghetto augmented reality.

[Anonymous No.856884]

I want to modify an RC car so that I can control with an arduino and my phone
anyone done this?

[Swifts !WiNDUPyWhk No.856892]

>>856884
Haven't done it, but I'd suggest you get a Bluetooth module for the Arduino.
This way you'll get a Serial Communication between the two devices.
There's a free App for Android that let's you send characters from a terminal over Serial connection.
Then you just need to get the Arduino to translate the received characters into commands for the RC car.
More research might lead you to a way to use the accelerometer in your phone or build a graphical interface, rather than just sending characters.

[Anonymous No.856916]

Hey guys, total noob here, i am trying to build this simple op-amp synth as my second project and it is not working. I get a faint buzz when i connect it to my amplifier (with tone) and it gets louder when i put my finger on one of the tone pot leads, but otherwise the filter section (LM 358 3,4 and 5) does not seem to be working correctly. I have rebuilt this according to the schematic 3 times now and i get the same result every time. Could this be because i am using a 300 mA adapter?

[Anonymous No.856917]

>>856916
schematic

[Anonymous No.856923]

>>856737
Beaglebone Black doesn't do graphics well. No clue about the possible latency issue.

[Anonymous No.856931]

>>856917
I don't see the buttons unless they're off screen in your picture. It's probably not meant to have all of them pressed at once.

You could also try connecting just the left half of the circuit to your speakers to see if that's working.

[Anonymous No.856933]

>>856916

measure DC voltage on the output of every op-amp. most should read around 4.5V. i dont see the LDRs or where the positive of the battery connects to the circuit.

[Anonymous No.856958]

>>856737
there will be latency in the tens of milliseconds, if this is acceptable then rpi is fine, if you are using it for feedback or some special application the beagle is the way to go, any ARM core with some SDRAM should be able to update in under 1 frame period.

[Anonymous No.856959]

>>855539
This. The FX-888D is the best all around iron you can get without breaking the bank. It's the blue one on the left side of this pic of my messy bench. I also have a cheap 80W weller with a big tip for soldering grounds to amp chassis.

>>855589
It's probably fine for light use, but if you're doing anything that needs precise temp control like smd/pcb work, a digital station is the way to go. Sometimes it's good to start with a cheap iron because you'll probably end up oxidizing the tip or otherwise fucking it up.

[Anonymous No.856967]

>>855980
Nice bench! Since you're in Yurop, see if you can get something from Russia. All the old soviet tech was tube powered, so I would imagine you could find an adequate tester. I work on audio amplifiers, so typically use my MaxiTest equipment, but I also have pic related for testing odd types and checking for grid leakage. One would imagine there's some sort of Yuropeen equivalent.

[Anonymous No.856972]

CS student here, I'm kind of a noob when it comes to electronics. I want to get deeper into that stuff because I ain't learning it at the university (well, I learned logical circuits + how a CPU works from scratch, but that's that). I want more than button+battery+lamp electronics. Much more.

Does it suffice to read random electronics 101 websites?
What tutorials/ebooks/websites do you guys recommend?
What equipment? The only electronicsstuff I have is some Arduino stuff that I'm using for my smarthome. Are there starterpacks that are worth buying?

[Anonymous No.856983]

>>856972
Buy
Breadboard, soldering iron, solder wick, flux, solder, power supply, multimeter. Salvage parts from old shit and experiment experiment and experiment. If you like it, then get an oscilloscope.
And no, dont get arduino starterpacks, they are overpriced. You can make your own arduino with an Atmel or buy a cheap clone from china.

[Anonymous No.856986]

>>856983
Thanks for the answer. I bought an Arduino starter pack like 2 years ago, that's what got me interested in electronics. Never went above a push button/temperature sensor connected to my smarthome though.

Anything special I need to think of when buying a soldering iron / power supply / multimeter? I have a soldering iron, but its top is as thick as a text marker.

[Anonymous No.857004]

>>856983
Not the CS guy but how do I get the point of understanding the schematics I see and even design my own circuits?

[Anonymous No.857047]

>>857004
It comes with practice, and there's plenty of tutorials on reading diagrams. If you want to build a circuit, try to google for some examples, pick components. As for IC's, consult the spreadsheet after googling the part number. Also learn the basic equations, and try to learn resistor coloring, altho resistors more come with practice and it is not neccesary, just makes it alot easier.

[Anonymous No.857050]

>>856986
If you already have a soldering iron and it takes different tips, i recommend a chisel tip - i use a 1.5mm one. Ricoh makes decent cheap power supplies but i totally recommend building your own since it's a great beginner project. As for multimeter anything cheap will do though if you're serious go for Fluke or other reputable brands.
As for other things, here's a good video:
https://www.youtube.com/watch?v=R_PbjbRaO2E
although you definitely don't need the 3000 dollars worth of gear he describes there, it should give you a basic idea of what you want to buy.

[Anonymous No.857119]

>>851753
Just got my oven controller.
Its really nice. Picked up the oven for $23.99 at target.

[Anonymous No.857127]

Never posted in /diy/ before, but wanted to start getting into building guitar/bass pedals, was wondering what would be the best/cheapest place to buy components (resistors/capacitors/pots/switches/etc).

Pic related, what I'm looking for parts for.

[Anonymous No.857144]

>>857127
yo I have a wooly mammoth pedal I can sell you for $60 shipped, I built it from a kit

[Anonymous No.857146]

I'd like to build my own midi foot controller, I find that most stuff built for guitarists are ridiculously ugly, expensive, or underdesigned.

I have plenty of soldering experience but don't know where to start with this...

Also, how could I make or where can I source parts for those rubber translucent pads used in midi controllers?

[Anonymous No.857147]

>>857144
That would be nice, but I wanted to do this on my own, ya know? Seemed like a simple but not too easy first project, and I love the sound the mammoth has on my bass (my friend has one)

[Anonymous No.857149]

>>851837
Or... Just don't breath the magic smoke.

[Anonymous No.857171]

>cannot into electronics
>see cheap FM transmitter at store
>sudden burst of inspiration
>take it home to solder on wire in place of useless antenna and replace resistor with smaller one
>no "ANT"
>five mystery resistors
>no wiring diagrams on the internet
>no relevant tutorials or forum conversations
>transmitter is already nearly destroyed just by taking it apart
next year for sure though

[Anonymous No.857172]

why do I hate circuits/EE related shit
when I look at it I want to barf, even though I did well on it in my general physics class so no reason to hate it, I did good
i dont even know why i hate it. i never did bad on it but for some reason hearing the words "ohm", "voltage", "resistor" make me so sick

[Anonymous No.857173]

>>857172
Tell me something you like and I'll explain how circuits/EE isn't that different.

[Anonymous No.857180]

>>857173
Soccer

[Anonymous No.857182]

>>857180
Something you studied in your general physics class.

[Anonymous No.857190]

>>857182
https://www.youtube.com/watch?v=9EPlyiW-xGI

[Anonymous No.857220]

Hello, ohm, I tried to mod my wi-fi for longer range, but I failed. I bought a 2.4 GHz 8dBi antenna, and some SMA plugs with cable attached. I then desoldered both original antennas, so the range decreased drastically (I was surprised that it worked at all). Then I soldered the cable to one of those circular things (pic related), and there was no improvement at all, compared to no antennas.
What I'd like to know is if this is caused by the cable being too long (2.5 m), or is my antenna faulty (when I check the resistance, it says it's infinite, but I saw many antennas where the shielding is shorted to the cable)? I checked for obvious things like broken cable. Also I think I did the soldering properly (shielding to the circular thing, cable to the middle).

[Anonymous No.857230]

Is glass - reinforced epoxy the least flexible common circuit board material?

I'm building a keyboard and my switches are PCB-mount only.

[Anonymous No.857237]

>>857220
1) you've melted through the insulation trying to solder the shielding to the ground plane. This is not how it's done. You remove the outer insulation then peel off and twist the strands into a wire. Then you cover it with heatshrink, leaving a little bit at the end exposed. You should now have what looks like two wires. Then you tin the shielding then solder the shielding wire you've made to the board. How you've done it, your antenna wire and the shielding should be shorted together.

2) your solder points are dry. Too much heat. They should be shiny and not a blob like that. You used too much solder.

3) what antenna are you using? The best b/g antennas I've found are the 7dbi dlink antennas that they don't make anymore. Where did you get your antennas? What brand are they? There are a lot of fake antennas. I see you have three antenna points but only two antennas. Why?

[Anonymous No.857238]

>>857230
You can use copper tape on anything you want. Saphire glass if you really wanted to do that. All parts are pcb mount I am pretty sure. Do you mean surface mount? What is wrong with membrane keyboards? Why does everyone want to build a cherrymx clone?

[Anonymous No.857243]

>>857237
I used a TP-LINK TL-ANT2408CL, bought it at a local electronics shop.
I'm sorry if I didn't explain myself clearly enough, that image is just one random image of a wrt120n I found on google, so those are the original solder joints. The third one is not populated by default, they probably reused some old design or idk. The metal thingies on the left and right side marked E1 and E2 are the original antennas.
What I did was desolder the original antennas, check the signal strength in the toilet (no signal at all without antennas), then solder on the new cable the way you said (although I didn't use heatshrink), and checked the signal again (no signal again). I also checked if I shorted it out during the soldering with my multimeter, and I clearly didn't.
Yeah my solder joints might have been ugly, but so were the factory ones, not to mention that it werked perfectly when I resoldered the original antennas.
This is why I think the only thing that can be wrong is the length of the cable (2.5 - 3 m), however I wanted to hear some opinions before cutting it down to 15 cm, as it costs a lot.

[Anonymous No.857263]

>>857230
Does aluminum core PCB fit to your definition of common?
If you want more rigidity, just bolt or glue your PCB on a steel plate or whatever.

[Anonymous No.857383]

>>855826
gief schematics!

[Anonymous No.857451]

>>856250
10A blows a 6A fuse never?

[Anonymous No.857452]

>>855826
Is it not traditional to have a "firewall" between the hot and cold sides, consisting of (at the very least) no copper, and preferably of airholes drilled through the PCP?

[Anonymous No.857477]

I intend to buy my first soldering iron and here's the question: should there be a heat setting? There a lot of tools which doesn't have that feature. Is it okay to solder semiconductors with 400-450 deg temperature if you do it quickly, less than a second? I don't know if I should buy tool made by native factory with heat setting or sertified foreign one made in China without it. They have the same price.

[Anonymous No.857496]

>>856967

HI

I just found a guy selling some tube testers

one of them is this one " TUBE TESTER TC-2 " (the cheapest hes selling)
also known as " CTR TUBE TESTER TC-2 " and he is selling it for 85 euro (93$) with all the documentation and box.

should I go for it, I need it for most European TV/RADIO tubes like ecc83,pcl82 and so on...

[Anonymous No.857497]

I'm making a High Voltage PSU and I need some kind of power control to make the high voltage output adjustable. (See pic related)
I was thinking about 555 PWM control with a MOSFET adding some big chunky caps to smooth the power going into the driver's MOSFET and finally to the transformer. The PWM would vary the amount of power going in quite efficiently, but I'm afraid the signal from the PWM interferes with the switching of the driver's MOSFET. The driver will be running at 15 to 30kHz, so I thought I should make the PWM run at a higher frequency, maybe 50 to 100kHz. ¿Would there be a problem with this setup?
I also thought about an LM317 and a TIP3055 BJT to act as some kind of heavy duty variable resistor, but I think this would be less efficient than the previous solution.

The high voltage output doesn't needs to be too clean, I'm not going to use it for precision stuff, just burning things up and making random experiments.

[Anonymous No.857506]

>>857451
>what is an exponential graph
it will blow at 11A pretty quickly, remember the rating of a fuse is how much current it can allow reliably, to pick something that blows at an exact value you have to under rate is based on the desired blow time as the graph shows.

[Anonymous No.857510]

>>857497
>I was thinking about 555 PWM control with a MOSFET adding some big chunky caps to smooth the power
This will work ok if you don't need stable output, if you do you'll need a feedback circuit to monitor the HV volts and or current. Also an inductor will work better than just large capacitors, since your switching frequency is high the caps wont react fast enough to suppress the transients, when using an inductor make sure you use a bypass diode to protect the MOSFET from the reverse current spike.
>I'm afraid the signal from the PWM interferes with the switching of the driver's MOSFET.
Should be a problem providing you bypass the ICs correctly, you should also consider driving the logic off it's own regulator to isolate a lot of the switching noise and will also mean you can use a switch mode psu for the driver since you're probably going to need high current depending on the transformer ratio.

[Anonymous No.857533]

If you wanted to remove all the components from a large board, could you use a propane torch on the back side and just shake them all off?

[Anonymous No.857534]

>>857533
Through-hole components often have their leads bent so they won't fall off just because the board is upside down and the solder is liquid; you've got to give them a pull. I propane torch might overheat them too. A heat gun is the normal way to do what you're talking about.

[Anonymous No.857535]

>>857533
yes, this works great, you could also use a heat gun if you don't want to risk burning things

[Anonymous No.857587]

>>857173
I liked mechanics

[Anonymous No.857655]

>>856677
christ, KT3102? who the fuck's numbering system is that? what does it even signify?

[Anonymous No.857661]

>>857655
Some Russian system. Dunno if it actually tells something or if it's just as useless as JEDECs system or various proprietary type number schemes.

Google would tell you it's roughly comparable to BC547. Not that it matters that much, the transistor isn't critical. Same with the zener, except that different diodes (even with the same type number) have somewhat different noise characteristics and you might want to test several diodes.

[Anonymous No.857662]

>>857655
> who the fuck's numbering system is that
Soviet Russia.

[Anonymous No.857669]

>>857451
Not in 10000 seconds in room temperature - typically.
The manufacturer guarantees that the fuse takes at least 30 minutes to blow at 150% overload. They don't give a guaranteed maximum time at 150% overload. At 210% overload they guarantee 2 minutes maximum blow time.

The graph is taken from Littelfuse 213 datasheet.

[Anonymous No.857761]

dis gon b gud

[Anonymous No.857892]

>>851762
what could go wrong ?

[Anonymous No.857902]

>>857496
TC-2 is a Heathkit. Buy it.

[Anonymous No.857903]

>>857497
variac>transformer>rectifier/filter
choose the transformer based on the highest voltage needed and adjust variac to suit whatever you happen to be working on

[Anonymous No.857954]

Any BMETs here?

How difficult was it to learn about fluoroscopes and CT scanners?

[Anonymous No.857955]

>>857496
find a manual for it online first, see if it supports the tubes you want to test

[Anonymous No.857959]

>>855628
There is, but you're better off selling that panel on ebay and buying a monitor. I'm just being financially reasonable.
If you still want to go ahead, vendors will ask you the model, sreial/sku & send you the board. Some might have sound, others might not. It will very likely not have any form of power, so that's up to you as well. http://www.instructables.com/id/How-to-Convert-a-Laptop-LCD-into-an-External-Monit/step7/Buying-the-LCD-controller-board/
Is about what I found when trying to do this with my old laptop.

[Anonymous No.857994]

what values should I use in this circuit for the resistors and capacitors?

[Anonymous No.857996]

>>857994
it's a toggle flip flop, by the way.

[Anonymous No.858002]

Hello guys

So I'm building my own MIDI controller.

http://www.instructables.com/id/A-Framework-For-Making-Affordable-Stylish-Modula/?ALLSTEPS

I'm going to build it following this guide.

I already have ordered my Teensy 2.0++ and more or less understand the whole thing.

The problem is that the electronics stores are very lacking as I live in a small town in Mexico.

It says I should get a CD4067BE Multiplexer, but I can't find that in any of the stores. They do have other multiplexers though.

My question is, can I find a different multiplexer that does basically the same thing? I'm just starting in electronics and am pretty uneducated in the matter.

I also can't find them online as they sell them in bulk (I would have to buy 315 at least).

Also I'm in a bit of a worry here as I have no idea of how much wire I'm supposed to buy. Any input would be appreciated.

[Anonymous No.858021]

>>853130
this thing would be rad for making drum and bass

[Anonymous No.858032]

>>857955

you can make different adapters for most of the tubes ...

you just need the right tube sockets ...

[Anonymous No.858085]

>>858032
And you need to research what's actually going on inside the tube tester to make sure you don't toast a tube.

Find a manual FIRST

[Anonymous No.858087]

how do I power a breadboard? Up until now, I've been using my arduino. There's gotta be a better way, right?

[Anonymous No.858095]

>>858087
If you can get a spare power adapter for a computer peripheral, or something that has a big black box on it that tells you a DC voltage coming out, take it, snip the connector off the end and strip it out to some bare wires. Make sure you know what voltage you're dealing with. If it's 5 Volts, you're dealing with what came out of your Arduino, if it's higher, like 9 or 12 volts, look up the 7805 voltage regulator, or LM340-5 (They're both the same thing) and use that to bring the voltage down to 5. The circuit for the 7805 involves about 3 or so components; resistors, capacitors; and should give you what you want. If you don't already know, the two seperated lines of holes down sides of a breadboard are all connected longways, take a multimeter, and you'll see what I mean. So you put the positive lead from whatever into one of those holes, usually near the top, and the negative on the other on, making sure they aren't on the same line, or you'll get the power supply REALLY hot REALLY quick.

I sound kinda bone-headed here, but there ya go.

[Anonymous No.858119]

is EEVblog the best youtube channel for electronics?

[Anonymous No.858122]

>>858119
It's a pretty good channel!
https://www.youtube.com/user/TheSignalPathBlog/videos
This one focuses really well on high end test equipment

[Anonymous No.858162]

>>857510
I'll try with MOSFETs then, but I might use capacitors since I have no idea how to design it with an inductor.
PSU > PWM MOSFET > Caps > Driver MOSFET > transformer
>>857903
A variac is way too chunky to fit into the case I already made.and would increase the cost 10x if not more.

[Anonymous No.858166]

>>858162
why are you using a two stage driver? this is something I've only seen used on things that are running straight off high voltage mains, since you already have a low voltage from the PSU just operate the PWM at the same frequency as the transformer needs to be driven, you then sense the output and change the width accordingly to change the voltage.

[Anonymous No.858175]

>>858119
Yeah, he's one of the best.
I'm actually thinking about starting a channel to teach basic electronics and possibly some mpre advanced stuff later on. Mostly for myself since the best way to remember something is to teach it and also because there aren't many channels on YouTube that help beginners get into electronics.

[Anonymous No.858212]

>>858175
Link here if you do it.

[Anonymous No.858216]

>>858212
I have a channel made already that I'll use for it if I do.

https://m.youtube.com/channel/UC6J1orXLhl6uEcymeZFRiCw

I only have two videos up atm and they aren't too exciting.

[Anonymous No.858237]

I've just begun soldering since a couple months ago, and so far, everything's been going good. I've been fixing video game consoles (with some good success) and generally fucking around with circuits to help me learn more.

Pictured is the soldering iron I'm using, some 9.95 Walmart iron I picked up and have been using. I know it's no Weller, but it's been getting the job done.

I want to use finer tips to solder smaller shit. Does any iron tip off of eBay fit? Is there a size standard to tip fittings? Or is it all proprietary to the iron model? I want to make sure it'll fit and get heat transferred to it.

It's brand is "Voltage Pro" with a model number TN25072B; not finding much info through Google. I'm gonna buy a better iron down the road, but I'm just looking for cheap solution for now since various tips are cheap on eBay.

[Anonymous No.858238]

>>851773
Noice Sillyscope man. I trained on the Goldstar.

[Anonymous No.858240]

>>851905
In the old days we used to use Mercury switches.

>Inb4 WWII old fuck
We used them in torpedo's, circa 2006

[Anonymous No.858243]

>>858237
the reason you're having trouble do small stuff is because that soldering iron is shitty, not because the tip is too big. chisel tips work infinitely better than conical ones because they transfer heat better. Also leaded solder is much easier to work with. You shouldn't be breathing in any of the fumes or sticking your fingers in your mouth regardless of the composition of your solder, so don't be a bitch about using "poisonous" leaded solder.

[Anonymous No.858326]

>>858002
There are other 16 to 1 multiplexers, but they probably aren't any easier to get. The biggest (very) common multiplexer is 4051, which has 8 channels. You could use two 4051s and an inverter to kludge together a 16 channel multiplexer. Consider ordering correct parts online.

[Anonymous No.858329]

>>857994
The component values depend on things like supply voltages, required output impedance/current and input pulse slew rates. You need to decide those first.

Download Millman and Taub's book Pulse, digital and switching waveforms. 1965 version should be easy to find. It spends lots of pages explaining how design flip flops. It calls them "binaries", though.

[Anonymous No.858345]

I bought this 24V 10A power supply from china, not too surprisingly it broke after a couple months. I saw that one of the two 2SC4138's was blown, replaced both, but it still doesn't turn on. The fuse isn't blown and I can't see any other damaged components, what else is there to check for?

[Anonymous No.858353]

>>858345
Resistances. You can use a very sensitive ohm meter to trace the bad component if you have a short on your 24v out. See "dave jones arducopter"

[Anonymous No.858357]

>>857119
pretty fancy! i have the LCD, and i'm making a swag toaster. Details about your tronics and or code?

[Anonymous No.858358]

>>858345
Do they have emitter resistors?

If you have a schematic post it.

[Anonymous No.858360]

>>858345
And measure the voltage on those mains filter caps before poking around or things could get exciting.

[Anonymous No.858364]

Is it possible to solder semiconductors with 30-40W soldering iron without breaking them? Cannot change the temperature, it's always 400-450 C.

[Anonymous No.858369]

>>858364
Yes, but if you're worried, you can use pliers or pincers as a heat sink during soldering. Pic kinda related.
You can also use a light dimmer to "dim" your soldering iron.

[Anonymous No.858370]

>>858353
I only have a regular DMM available, and I did check dave jones arducopter but I don't see the connection.
>>858358
Don't have schematics, couldn't find any. The 2SC4138s have some resistors hooked up to the emitter, the other one doesn't seem to.
>>858360
It was unplugged for quite a while before I started doing anything but they are discharged.

[Anonymous No.858373]

>>858369
Yeah, I thought about using tweezers for that. What about soldering time? It should be quick, less then 1 second?

[Anonymous No.858377]

Is an ISCET certification worth it?

[Anonymous No.858382]

>>858345
How similar is the hot side of this?

[Anonymous No.858384]

>>858345
>Without some form of a load the supply will probably destroy itself, because the TL494 cannot shut down permanently, meaning that energy is being supplied to the secondary without anywhere to go. This causes large primary voltage spikes that destroy the primary switching transistors.

http://www.users.on.net/~endsodds/smps.htm

[Anonymous No.858386]

Is this acceptable soldering iron for a beginner?

[Anonymous No.858387]

>>858386
Kauf eine lotsation damit wirst du glucklicher

[Anonymous No.858388]

>>858377
it would give employers more confidence I suppose. but it is just a 50$ exam.

[Anonymous No.858391]

Tidied it up just yesterday :^)

Mostly I do simple fixes on consumer electronics and tinker with arduino stuff.

[Anonymous No.858395]

>>858386
I started with something similar long ago. Now use a weller station.

[Anonymous No.858429]

>>858166
You mean changing the duty cycle and the frequency at the flyback transformer with the same MOSFET and driver?
I thought the duty cycle of the flyback transformer should be kept constant, so I tried to vary the power going in instead with the PWM circuit.

[Anonymous No.858462]

>>858391

you should get another screen

[Anonymous No.858468]

>>858462

I'm running out of desk though.

[Anonymous No.858596]

>>856967
>>857902
>>857955
>>858085

Okay I bought the TC-2 tester and am pleased with it ...
after doing some maintenance on it, replacing few resistors and capacitors it seems to work, but don't have a for sure shorted out tube to test it out completely

pic related ( testing a PCL82 also known as a 16A8)

BUT THERE IS A PROBLEM !

I can test some of the European tubes, but don't find the data for the others

what should I do, it only has american tubes in the tube chart,with a few European equivalents

[Anonymous No.858651]

>>857761
Will this be one of those things which appear like they display an image when you wave them or rotate them? If yes i assume you used RGB LEDs, what type are they?

[Anonymous No.858667]

>>857761

beautiful

[Anonymous No.858836]

Are there any opamps with input capacitance even close to the LTC6268 (200fF)? I can't seem to find anything that's even under a picofarad, and really don't want to use an opamp that sinks more current than the rest of my system combined (~18mA).

[Anonymous No.858855]

>>858836
I don't understand how a pF input capacitance could cause an op-amp circuit to draw more than 18mA. What's your circuit like, and why do you need it to be so low power in the first place?

[Anonymous No.858864]

>>857127
As someone who build pedals, I would buy from tayda electronics. Good, cheap, reasonable shipping times. Everything you would need for a pedal (including enclosures).

If you intend to get into electronics besides guitar stuff, I would recommend learning how to use the search indexes of sites like digikey and mouser.

Tayda also runs pretty decent coupon codes on their facebook page.

[Anonymous No.858872]

>>858855

It's not my circuit that's drawing 18mA, that's the rated quiescent current of the amplifier.

I'm looking into non-contact ECG electrode design; low input capacitance/high input impedance is preferable because it minimizes low-frequency voltage noise from current noise integration (which is non-negligible since you're measuring a microvolt signal off of a high-impedance node) and also reduces noise from impedance variation due to electrode movement.

I'd prefer it to be low-power because the amplifier has to be built into the electrode, and 60 milliwatts * 10 electrodes of heat dissipation strapped to your chest seems less than ideal.

[Anonymous No.858876]

>>858872
LMC6001?

[Anonymous No.858922]

>>858872
I've had those attached to me, if power usage actually mattered they wouldn't have included LEDs in each of the sensors, they also had this neat feature where if one of them disconnected it would start flashing so you could fix that instead of fucking around with all of them until you got a signal back.

[Anonymous No.858932]

>>858872
Do you have any estimate about the other parasitic capacitances? They'll easily dominate the total input capacitance, making the opamp input less important.
INA116 has been used in such circuits and it has much lower quiescent current. It's an instrumentation amplifier, though.

How are you going to bias the amplifier inputs?

[Anonymous No.858934]

>>858596
Uh, that's why anons told you to check the manual beforehand.
Check the tester manual and schematic, download tube datasheets and make educated guesses about what can be tested and how.

>but don't have a for sure shorted out tube to test it out completely
Take a tube, short cathode and grid (or whatever) together with a wire. Test.

[Anonymous No.859115]

>>857127
www.tubesandmore.com
You won't learn anything doing veroboard pedals. Work from a schematic and do your own layouts on perfboard.

[Anonymous No.859126]

>>858596
Yuropeen and Murrican tubes are mostly the same, but hey use different naming conventions.
http://www.worldtubecompany.com/mm5/merchant.mvc?Screen=TSL-LETTERS
Use the info at this link, and find some yuro versions of pic related.

[Anonymous No.859145]

3 years ago I bought an arduino uno out of interest but never did anything with it and recently I bought some more things to go with it (LEDs, breadboard, resistors, wires, etc.) because of a sort of rekindled interest in electronics/physics related to electronics. I signed out a tutorial book from the library but going through it I feel like I'm just copying and pasting whatever is written, not really thinking about anything or understanding anything. what do
how do I actually learn electronics

[Anonymous No.859154]

>>854610
Just the bare minimum: a bachelor's degree. Pic related: my alma matter.

And I work in "consulting" aka designing electrical systems for buildings. The microelectronics is more of a hobby although I was formally educated in it a long time ago.

>>855150
Actually sometimes I do learn new stuff from /diy/ (and sometimes from /out/ and /n/ too).

[Anonymous No.859242]

>>859154
oh uofa nice im attending uoft right now

[Anonymous No.859256]

>>859145

You need to find a project that you are passionate about, and then learn electronics as a means to realizing that project.

Have a look on hackaday, instructables, reddit, for ideas for projects that strike your fancy.

Maybe an LED matrix, a line follower robot, a laser pointer? an audio amp?

[Anonymous No.859370]

If anyone is interested in old shit, I've dumped some pics here. 60s and 70s as far as I can tell.

>>859153

[Anonymous No.859409]

Can I ask for some advice? I'm trying to teach myself some basics for a simple project, but I can't for the life of me figure out transistors. The transistor here has its pins listed from left to right as B C E and those are 390 ohm resistor. No matter what I try, I can't get the 2nd led to fire. Also, should I connect the arduino and the battery grounds?

[Anonymous No.859411]

>>859409
looks fine 2 me, are you 100% sure the LED isn't rotated the wrong way around? also it looks like your second power supply is floating, if they are separate you need to tie the two grounds together or no worky

[Anonymous No.859412]

>>859411
I just connected the grounds. And the LEDs are definitely oriented right.

[Anonymous No.859413]

>>859412
whats your other leds driving setup? it almost looks like the resistor side is connected to ground on the arduino, in that case the base is always at 0v, you need to attach it to the other side of the resistor to have it actually have voltage.

[Anonymous No.859415]

>>859409
what kind of transistor is it? N channel or P channel?

[Anonymous No.859416]

>>859415
Or npn or pnp lol. Just noticed the B C E.

[Anonymous No.859417]

>>859413
That did it. Thanks. So the base needs to be connected to the positive side of the load?

>>859415
Package calls it a darlington transistor. No mention of N or P.

[Anonymous No.859418]

>>859409
what is the part no of the transistor

[Anonymous No.859419]

>>859418
TIP120

[Anonymous No.859420]

What's a good cheap AC power supply?

Alternatively, how can I regulate 120VAC from my wall play with? Preferably without having to make a step down transformer.

[Anonymous No.859424]

>>859420
>What's a good cheap AC power supply?
You'll find a 120v input step down transformer in 90% of consumer electronics (VCRs, tape decks, etc). /diy/ has some real retards who like to show off the $5 worth of random resistors and diodes they spent hours desoldering, but there are cases where salvaging is the best option. A new transformer like that is around $25. Alternatively you can go to a thrift shop; most of them will have a huge box of random wall-warts, which are just a transformer and rectifier.

[Anonymous No.859427]

>>856740
MATLAB + Stereo Vision. Works well if you have a super computer though

[Anonymous No.859535]

I don't have an oscilliscope

I'm trying to buy one of these chips from craigslist along with a few extras https://en.wikipedia.org/wiki/Texas_Instruments_SN76477

does it seem like a viable project for me to set up a circuit with that chip and possibly drive it with an atmega328p?

[Anonymous No.859875]

>>859535

you sure can but why would you, when you can get much better results with software synths on a computer or smart phone. you get a lot more squeals and screeches with much less work.

[Anonymous No.859905]

>>859875

because
a. it's a cool chip
b. software isn't hardware
c. I have the chip anyway

[Anonymous No.859913]

>>859905
looks like a cool project, i've always wanted to play with one of these chips myself but i have zero musical talent, i can't even flick my fingers reliably.

there's definitely an advantage to connecting it to an MCU, you could add some accelerometers and make it a motion controlled device or just a little tracker/midi player. good luck!

[Anonymous No.859958]

New thread:

>>859954
>>859954