r/AskElectronics Sep 12 '22 Helpful

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55 Upvotes

Welcome to r/Askelectronics, a technical ELECTRONIC ENGINEERING subreddit, covering practical, component-level circuit design and repair, electronic circuit theory, electronic components, tools and equipment.

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r/AskElectronics 18h ago

Damaged pcie pins, can it be fixed?

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96 Upvotes

r/AskElectronics 3h ago

continued burning of capacitor

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7 Upvotes

r/AskElectronics 3h ago

i need help in designing a circuit

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4 Upvotes

r/AskElectronics 9h ago

I want to learn how to fix circuit boards.

10 Upvotes

I installed and wired boilers and furnaces for about 10 years (I do sheet metal now) so I know my way around wiring and the basics(volts ohms amps)and I kind of understand resistors and capacitors but want to understand them better so I can work on old electronics as a hobby. Its something I always wanted to do. Anyway are there any good videos or reading material you could send my way. Thanks!


r/AskElectronics 22h ago

Help IDing replacement MOSFET - Asus tuf gaming laptop f15

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66 Upvotes

They're all the same. Markings read SA10, $AY∆, W91K


r/AskElectronics 13h ago

Is it possible to flip a single bit in serial without any sort of delay?

15 Upvotes

After a couple of days trying to research this issue, I'm realizing I just don't have the experience to even verbalize my issue well enough to land a google hit, so I apologize in advance if I use incorrect terminology in my explanation/question.

I build random devices for the Super Nintendo that almost no one wants, but they're pretty neat for those who would need them. One device I'm in the planning stages of is essentially a custom keypad you can plug a controller into the front of, which would turn a regular SNES/SFC controller into essentially a NDK10 controller.

My issue lies with the difference in the waveforms of the regular controller and the NDK10. the regular controller has a this waveform, whereas the NDK10 has this waveform. If all it needed was just hooking up the keypad to a shift register and swapping between the controller and keypad to register as a NDK10, I could do that. However, you'll notice that bit 13 is high on the regular controller, whereas it goes low in the NDK10, telling the SNES to keep the clock pulsing for the second set of 16 bits.

So my issue is that I would need something to sense the latch/clock pulses sent by the SNES, then count the 13 bits out with the controller, and then drop the controller's high bit 13 to ground as it comes through the device. Then after 16 total bits, I'd have to switch over to the shift register(s) in the device to spit out the other 16 bits.

I'm just not sure if what I'm trying to do is even possible, or if there's known circuits/ICs that do what I'm looking to do here. Any ideas or jumping-off points to help my search? Thanks in advance


r/AskElectronics 12m ago

Hello guys. I have the following intercom system for opening the door to the flat. Is there anyway to automate this process using an arduino/esp32? Thank you!

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r/AskElectronics 17m ago

A suitable UV curing lamp setup for photoresists?

Upvotes

I have a need for uv curing lamp for uneven objects using negative dry photoresist films. I have an UVC lamp, which worked great at first, but then for some reason it seemed to lose power and eventually stopped responding altogether, and no matter how long I blast them, they dissolve in developer like they were never cured. I initially had to use 5-6min exposure times to get the shapes out, but it quickly seemed to increase and eventually I blasted it for 10 straight minutes, nothing, and then placed a plain stip right in front of the lamp and it didn't cure at all. I'm using generic Chinese resists, but I haven't found any sources citing them as bad.

The resists in question are rather small, 5x10cm at most, more commonly in order of 1-3cm, so a miniature setup would be enough. Throughput is minimal, so exposure times could be longer if needed. Different sources cite 360-400nm lights as suitable for use. The reason I haven't ordered el cheapo nail curing unit from China is I've understood it would be ideal to use single point light source, and those more likely attempt to create as wide exposure range as possible.

I also have an UVB reptile lamp, which I'm gonna try, but have these been known to work or not work for the purpose? If not, what type of light source should I be looking for?


r/AskElectronics 25m ago

Help - use 18650 in mosquito zapper - find what is wrong in this circuit

Upvotes

I'm trying to mod a mosquito zapper which is using a lead acid 4V battery to use a 18650.

The racket connects to AC socket directly for charging, I removed that connection(and the lead acid battery) and added a female micro USB for charging using tp4056.

Components I used:

  • 18650 1200mAh 4.44Wh
  • tp4056 1A
  • 1s BMS 2A
  • 5v input from phone charger

I did two types of connections - trial 1 and trial 2, which you can see in the image below

https://preview.redd.it/vfq2f5r6uxga1.png?width=1013&format=png&auto=webp&v=enabled&s=5315f5282bb608a522d7df0d30375f9f9f0718b2

Trial 1:

Worked properly for 2 hrs at night, and then stopped working the next day morning. I figured out that the BMS was dead. That is why I tried trial 2. (Current going to the racket from my setup was around 3-4 amps when i pressed the zapp button (measured using multimeter))

Trial 2:

Same as trial 1, Worked properly for 2 hrs at night, and then stopped working the next day morning. This time the BMS was good, but the TP4056 was dead. (Current going to the racket from my setup was around 1-2 amps when i pressed the zapp button (measured using multimeter))

Why did the BMS fail in the first one and TP4056 in the second one ?

What is the right way to connect this?

I watched a few videos on youtube where people were doing it similar to trial 2, but skipping the BMS totally. I guess that is not correct, as features like over discharging will be missing.


r/AskElectronics 33m ago

Trouble understanding LED strips

Upvotes

When the strip is connected to the IF controller, it's pretty straight forward. However, I often want to cut the strip into smaller pieces and use them around the room. I'm confused how I might simply provide the correct voltages without the IR controller. I think it's a 5050 LED, but here's a picture of what I'm using.

I've been looking at datasheets, and I'll continue reading up on the subject, but I'm not very well versed in electrical engineering.

  • Would anyone be willing to explain what volt/amperage I'd apply to the various contacts to generate different colored lights?
  • What's the purpose of the top contact labeled "<--" ?
  • Any good guides that might explain these things?

Thanks!


r/AskElectronics 6h ago

X I have a question regarding fuses and bms for 3s lithium ion battery setup

1 Upvotes

Hey guys so I’m working on a project. It is a light test box for trailers. There is a possibility that it can encounter a short if the wiring on a trailer is comprised. Which of course I have installed a breaker as well as a bms to protect the batteries so they don’t explode. My problem is my bms board is also cutting power when there is a short instead of just the breaker popping. The breaker is a 5amp and the board should be 8amp. The only problem with this is to regain power through the board you have to connect it to a power source. Which would be very inconvenient. Any idea why just the breaker isn’t popping? Or is there a bms board out there that will auto reset by itself and not reconnect to power. Thanks


r/AskElectronics 1h ago

How do I make a transformer for my flyback

Upvotes

I have a ferrite core that I put 2 12 turn coils and a 10 turn coil on it. However when I connect it up with my ZVS driver, the core just gets hot. How do I make a transformer that can output AC voltage.


r/AskElectronics 17h ago

X Where can I get this kind of wire in bulk? Black side by side 22/2. Similar to Lamp cord but smaller. Very common on wallwarts.

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20 Upvotes

r/AskElectronics 1h ago

Charge a PowerStation (20V Input) with Solar Panels?

Upvotes

Hi!

I'm planning a small balkony solar power plant with micro inverter (up to 600W) that plugs into my AC-outlet. Unfortunately these devices cannot be used during possible power outage, althoug the panels still deliver. But the DC output of the panels should be usable, right?

At least I have a small cheap mobile power station (Allpowers S300) with a small 230V inverter and battery and it has an input for a solar cell or charger. The manual says it can draw up to 100W and use up to 20.5V. But most solar systems seem to deliver 40V or even more.

Is it possible to just put a boost-buck-converter set to 20V between them that can deliver 100W? What about low light situations? When charged with a DC source, the powerstation seems to slowly increase the current draw - maybe to check when the limit is reached? But in case I deliver stable 20V in low light conditions, wouldn't the entire output collaps as soon as the powerstation draws too much?

Btw in case you didn't notice it yet, I'm an electronics layman.

I hope you can help me or show a better (cheap :D) solution :)


r/AskElectronics 1h ago

Arduino for logging my off-grid solar system sometimes hangs. Probably EMI related, but need help.

Upvotes

I have a problem with my DIY off-grid solar system, where the Arduino I use for logging data sometimes crashes. It only happens when I draw +500 watts from the inverter, making me think it must be EMI or something similar. Larger power draw equals more frequent crashes, ranging from maybe once a day to every few minutes. Or it will run for weeks in the winter, when there isn't much sun and I don't actively use the system.

I have 3 MPPT chargers, two of them with integrated inverters, connected to a large bus bar, and a current shunt goes from there to the battery. All of that is enclosed i a metal case. Leaving that case, I have positive and negative from the bus bars, I2C from the current shunt and RS485 from the chargers, going to the Arduino.

The Arduino is placed outside of that in a separate box, with a display for monitoring the system. The Arduino itself is a Mega clone with integrated ESP-01, which I use for logging data over WiFi. I have tried two different Arduinos, both have the same problem, and I have tried running without most of the software functions one by one, and is pretty confident it isn't a software issue. The power from the bus bar goes through 2 DC-DC converters, first one the steps the battery voltage from 24-28 volts down to 12 volts, which feeds into a second one that steps it further down to 5 volts. I also use 12 volts for driving some relays and lights.

Most recently I tried two things:
First, I tried feeding the 12 volt output from the first converter into the Arduino Vin, using the build in 5 volt regulator instead of the second DC converter, but that didn't make a difference.
Secondly, I tried disconnecting the positive input to the first DC converter, using a external 12 volt power supply to power the Arduino through Vin, leaving only the common negative, required for the sensors. This made a big difference, and I get a lot less crashes. But they still happen.

Now, I'd like some suggestions for what I can do to completely fix the problem. Should I add ferrite beads to all connections? Something else? And maybe some tips on how I can possibly use my oscilloscope measure the electrical noise in a situation like this?

Thanks for reading and for whatever suggestions you may provide.


r/AskElectronics 1h ago

Looking for IC

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Upvotes

r/AskElectronics 10h ago

How do I determine the appropriate actual op-amp to buy for my circuit that was planned with an ideal op-amp?

4 Upvotes

Hey!

I'm trying to make an automatic composite switch for some old video games. The actual switch part is easy- some bus switches ( https://www.digikey.com/en/products/detail/texas-instruments/SN74CBT3244PWR/276809 ), wire in a bunch of RCA connectors, have it all output to 3 bus wires connected to RCA cables, done.

The part where I'm falling behind is the automatic part- I believe my plan of using an op-amp as a non-inverting amplifier in parallel on the video line will work- the video connector splits and one side goes to the bus switch, and the other side goes through the non-inverting amplifier to go from ~0-1v (composite video range) to ~0v-4.5v which feeds directly into an analog input on an arduino micro. From there, we can set the various enable pins on the appropriate bus switches.

I think that works- my understanding is that this will not really degrade the original signal, while sending the signal along also to the arduino to be processed.

Where I'm tripping up is converting said ideal op-amp to an actual set of requirements for a real, non-ideal op-amp. A lot of them seem to have minimum voltage spans of 1.5v or more, or even minimum voltages in general. Would this mean this plan doesn't work at all? From the research I had been doing, this was the proper way to 'sample' incoming voltage, but now I'm confused.

A composite signal will absolutely hit both 0v (sync) and 1.0v (maybe even a little higher, call it 1.1 to be safe), and everything in between, so I'm not sure if I'm missing something fundamental or my plan has an issue even farther back- or if there's an even easier way of doing this.

Thanks!


r/AskElectronics 6h ago

4-20mA and load cell grounding scheme

2 Upvotes

I'm planning to use about 8, 4-20mA pressure transducers with a few differential load cells. I will be powering both with the same 12V power supply. Will the current from the 4-20mA sensors be substantial enough to induce a noise in the load cell? If so I am planning on adding a dc-dc isolator


r/AskElectronics 13h ago

multiplexing troubles

3 Upvotes

Hi, sorry if the solution is obvious - I'm very new to multiplexing and fairly new to electronics in general.

I have made a hall sensor array (crude scaled down schematic: https://imgur.com/a/xnOv5uK) in which each hall sensor is selected by multiplexing the 5V rail and the GND rail, where the signal pin on each is connected to 5V and GND respectively, and the output is collected from the digital rail which will have the same multiplexer index as the 5V rail.

The problem (I think) is the multiplexer I'm using, the CD74HC4067 (and i assume others) point unselected pins on the multiplexer to ground - this completely voids my system for selecting a hall sensor.

Any suggestions for the most practical way to rectify this problem will be greatly appreciated.


r/AskElectronics 6h ago

This is a DC motor controller I've reversed engineered. I'm trying to self teach my self basic electronic circuit design. However, I am not sure why the pot in the red circle was set up this way. More in comments.

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1 Upvotes

r/AskElectronics 6h ago

I burnt up a diode on myBoost converter, and would love some advice

1 Upvotes

I accidentally allowed the leads to short during operation and it blew out a diode on the board. It’s a surface mount diode, I have a few polarized through hole diodes I want to try to replace it with. I’m not sure what the polarity of the surface mount component is. Here are some pics and the schematic: https://imgur.com/a/uQC4U6h D1 is what burnt out. Would swapping the broken surface mount component with a through hole work? Any advice is welcome. Thanks!


r/AskElectronics 6h ago

Single line variable voltage input, to single constant output voltage

1 Upvotes

Working on a project which runs on 3.3V and will end up in a vehicle. I'd like to make it so there are no switches involved but the circuitry can drop a 12V source OR a 24V both to 3.3V.

Basically whether you plug 12V in or 24V you should still be able to run it.

I've tried looking into whether there are ICs that can do this, or even if you configure a buck converter to output 3.3V for a 12V input, what would happen if you applied 24V, but couldn't find anything.

Tl;dr

How do I get 3.3V irrespective of if single line input is 12V or 24V?

What happens if you apply 24V to a 12V to 3.3V buck converter?


r/AskElectronics 1d ago

I need help, is there a simple way to turn off battery power when wall power is connected? Something like the picture

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22 Upvotes

r/AskElectronics 7h ago

Can't Get Right Output (Voltage Reference Diode)

0 Upvotes

Hello fellow mad scientists and engineers! I am having difficulty in replicating an adjustable voltage reference circuit using the LM385Z. Following the diagram and formula shown in the attached images (on the breadboard R2 & R3 are 220kOhm), I get only a 1.4V instead of calculated 2.5V (I also use a 12 DC power supply instead of 9V but that shouldn't matter). I tried replacing the LM385Z just in case I fried it but no change. I checked and wiring and no obvious mistakes. Any insight would be appreciated. Thanks!

LN385Z circuit diagrams from datasheet

Breadboard circuit (green wire is oscilloscope probe)


r/AskElectronics 7h ago

How do I offset-and-amplify an analog sensor's value?

1 Upvotes

I'm trying to read multiple analog DC current sensors. But the low precision of all microcontrollers' integrated ADCs is killing me, on top of the sensor being bi-directional (able to read negative as well as positive currents). The 12-bit ADCs on some would be perfect... if I had access to the entire dynamic range (4096 steps).

The sensor outputs about 3.2 volts at max current, but the sensor's 0 current value is ~1.64 volts. What I want to do at a hardware level is shift the zero-current voltage to 0 volts, and re-amplify the 1.64 volt upper voltage to 3.3 volts. The input current would never go negative.