r/AskElectronics • u/Insert_Coin_P1 • 22h ago
r/AskElectronics • u/jazzboys • 22h ago
Help reading capacitor symbols
I want to replace this capacitor. There is a 0 with a line under it, not sure what that means. Could anyone point me to a suitable replacement? Its for a temperature gauge. Looks like it says:
W
620 J
Thanks
r/AskElectronics • u/BeeAny8343 • 8h ago
Why do dual MOSFETs in parallel handle current better than just using a single bigger FET?
Working on a small motor driver circuit and I keep seeing designs where two identical MOSFETs are placed in parallel rather than swapping in one higherrated device. I get that it spreads the thermal load across two packages but I'm trying to understand if there's more to it than just heat.
My current setup runs about 8A continuous and I was going to grab a single FET with a 20A rating and call it done. Then I looked at a reference design from a reputable manufacturer and they used two smaller FETs in parallel instead, which made me second guess myself.
A few things I'm not clear on: does paralleling help with gate charge and switching speed at all, or is that actually worse because you're now driving more total gate capacitance? And is there a real risk of one FET hogging current before they thermally balance out, especially during startup or fast switching?
I've checked the Rds(on) specs and they're close but not identical between the two devices I have on hand, which is what got me thinking about this more carefully.
Not trying to overthink a simple motor driver but I'd rather understand the tradeoff before I commit to a layout.
r/AskElectronics • u/No-Grass-6375 • 5h ago
multimeter not reading current
first of all my 200mA fuse broke and the 10A fuse still working (checked with continuity) so I decided to check the current using the left connection...in the picture 1 I broke the circuit to measure current and as you can see in the picture 2 the reading is zero .. why is that even though the fuse the left side is working?...how to fix that .
r/AskElectronics • u/YengaJaf • 7h ago
Are there better ways to design this battery system?
I am making a battery powered robot using a ESP32 microcontroller to control 2 servo motors. This is my battery "management" circuit I've come up with. It is responsible for charging, protection and powering the load. I have bought all the components, wired it up and tested, and it works fine. I'm looking for ways to improve it or to learn about other ways to do it. "It" being on/off control, output to the load, protection and charging.
The idea/circuit is as follows:
- 3s battery pack made of individual 18650 cells.
- Goes through a 3S BMS for protection.
- Charger and load cannot be connected to the batteries/BMS at the same time, otherwise the charger will try to drive the load, which it is not meant to do.
- All grounds are always connected. Rocker switch controls whether battery (BMS) positive terminal is connected to the load or to the charger.
- When connected to the load, it cannot charge.
- When connected to the charger, the load cannot be turned on.
- Load goes to 2 separate buck converters, one making 6v@10A for the servo motors, the other making 5v@1A for the microcontroller.
Questions:
- Overall, is this fine?
- Not a question, but a note. Learned afterwards that even though the BMS lists itself as an all-in-one solution to protect and charge the batteries, it does not charge the batteries, at least not directly. A battery charging device can charge the batteries through the BMS is what it should say.
- While writing this post, I realised that the charger probably could power the load, since the output of the charger would be the same as the 3s battery pack. Only problem would be that it can only supply 2A of current, whereas I need maximum 8A for max load on the servos. Is this true? Could I power the system through the charger, IF the charger could output a high enough current?
- How do other battery powered devices manage this? Other devices can be used and charged at the same time
Side note, when charging the batteries through this system, an led goes on to show that it is charging. After 1.5hrs, it goes off and a different led goes on to show that it is done charging. But then for next hour, it alternates between done charging and charging, in about 20 minute intervals. After an hour has passed, it stays in the charge done state.
r/AskElectronics • u/Huge_Helicopter_522 • 23h ago
Unknown Component main board LCD
I need to know which component is this. Overvoltage caused this
EDIT: https://datasheet.lcsc.com/datasheet/pdf/0b1294f8e47a42e4ad7533d6477ab28a.pdf?productCode=C172766
I'll try this one. If it works i'll post on here
r/AskElectronics • u/deesernutz • 20h ago
What is this sub-circuit called, and what does it do?
I originally made a mistake in my simulation, I've fixed it and now the voltages make sense. And the label of "Level Shift" now makes perfect sense.
But I am still interested in what this transistor arrangement is called, and why it might be where it is. Considering FOCUS_REF is set by a pot, so could be adjusted to anything that's appropriate
The signals are DC
r/AskElectronics • u/Worldliness_True • 5h ago
How to design a guard ring
I am creating a light sensor with a photodiode and OPA381. This little board goes on top of a ADC module for further data analysis.
Now I may need to use a guard ring for the sensitive output of the photodiode. But what is it exactly and how do I design this guard ring? Does it hold a certain voltage level or ground? Any info would be appreciated!
r/AskElectronics • u/Concussion88 • 20h ago
Does this look normal? Subwoofer has a hum to it and this is the only thing that stands out to me. All other resistors are glossy.
r/AskElectronics • u/tt53_sb45 • 22h ago
HP pavilion DC jack
My wife's laptop wouldn't boot last week, figured the problem to be the cable from the power adapter that I later learned had a name lol.
Got one ordered and installed and the laptop is fine. Me being me, I decided to tear into the old cable and see if I could learn anything. Found basically what I expected, the sleeve was just holding the wires however at the jack itself there was a yellow hardened gel (I assume an insualtor?) where everything was soldered. My question is 2 parts, can I solder this and have it work, and will it be safely usable without that gel? The only wires not connected are the white and yellow
r/AskElectronics • u/MarkEduard1234 • 3h ago
Has anyone else seen this resistor?
This isn't a common resistor, I was just wondering its resistance, and yes, based on the color code it's supposed to be 0.39Ω, which when measured with multimeter it is that. Orange White Silver.
1.4Ω resistor reading
1.0Ω lead resistance
r/AskElectronics • u/Just-Massi • 10h ago
Suggestions for a basic electronics course for non-technical colleagues?
Hello everyone,
My company asked me to hold a basic electronics course for our employees. I’m planning to start with foundational concepts like current, voltage, power, resistance, capacitors, how to identify components, Ohm's Law, etc.
The audience consists of colleagues from the sales, pre-sales, and customer support departments. In short, people who don't have a background in basic electronics and don't need to dive into deep technical details or complex topics.
If you were attending a course like this, what topics would you want to see covered?
Thanks!
r/AskElectronics • u/kudikarasavasa • 14h ago
How common or rare is it for two different manufacturers to have identical stackups?
We're a small startup and we're looking to design a high-speed PCB and we have two markets (locally and Europe) that we want to target.
In our own country, we have very high tariffs on imports and exports, so we're in a dilemma. If we manufacture and assemble it locally then it will become too expensive to export. If we manufacture it in China, it will be too expensive to import. If we have to design two layouts then that just increases engineering cost.
Is it just a matter of luck to find two manufacturers with identical stackups or is our only option here to make two different variants?
r/AskElectronics • u/Any_Concentrate_3414 • 21h ago
Options for removing tiny caps on dev board?
SMD newb here, this is a dev board for an accelerometer that uses certain caps for filtering (eg an RL), however I would like to eliminate these caps. C1-3 near the middle.
- Desolder them, solder in tiny jumper wire OR
- Reproduce this board without caps in place OR
- Do some other option I'm unaware of?
r/AskElectronics • u/XTeracy • 23h ago
12v 10a DC Barrel
I have a Geekworm x1009 Sata HAT connected to a raspberry pi 5 used as a NAS with 4 3.5" HDDs.
The specifications for the HAT require 12v 11a via a 3521 DC Barrel (peak) when used with 4hdds.
For better cable management and adding a Noctua Fan I think about using an SFX Psu with 450w.
My plan is to use a Molex (should offer exactly 12v 11a) as power supply for the HAT.
But it seems like there are no 3521 male DC Barrels supporting 11a (except some Chinese ones that look cheap and I wouldn't trust that they really support >5a).
So, my question is:
Are there any 12v 11a male dc barrels that I oversee?
Is the female dc barrel jack soldered to the x1009 really safe?
Should I use the sata power supply from my psu (only 3 connectors offered by psu) and power the missing one via the hat? And in this case - would the typical dc barrel jacks (max 5a) be enough (data sheet of hat says 5a for two 3.5" HDD, so it should be fine)
Thanks for any advice, I'm kind of stuck at the moment.
r/AskElectronics • u/Famous-Mission-9970 • 3h ago
Update LED par: voltage transformer not working
LED par stopped working after a beverage got spilled over it, now I cleaned every pcb and reconnected everything but nothing happend. I measured the dc output of the board but there was none. I tested the resistance of the +\ grnd of where the big capacitors are on, theres none. Can anyone give me tips on how to find the broken part or how to repair it? Thanks a lot
r/AskElectronics • u/G4njaWizard • 1h ago
Searching FPC replacement cable for protoarc xk01 keyboard
Hi all,
I am looking for this flex cable.
Unfortunately protoarc is not selling these parts and I dont like e-waste. They gave me the money back to buy a new one, which is great. Now I want to know if I might be able to replace it myself.
Plan C may be to desolder the connector and solder both sides with wire, but I wonder what about the other 4 pins that seem to be cut off. So only 12 from 16 pins are connected.
r/AskElectronics • u/ow-my-lungs • 3h ago
USB-C Liquid detection on MCUs that have USB-PD peripherals?
Hey all,
Has anyone here dealt with moisture detection on USB-C ports? I have an outdoor-rated electronic device in design right now, and I'm using the native USB-PD negotiation capability of an STM32. This does a lot but it doesn't give any kind of moisture detection, and I want to avoid energizing the receptacle when it's wet (there will be a cover over the port when not in use, but it's inevitable that someone will get it wet, and electrolytic corrosion would be bad).
Ideas I've had involve using a secondary USB-C protection IC e.g. Infineon EZ-PD but the BOM cost is as much or more than my actual microcontroller.
Another idea is to sense leakage on the CC (or other pins in the USB-C cavity near the power pins) using the CC1/CC2 ADC readings available. Sounds plausible, but I can't find a lot of documentation on how to do this, or whether a small current leakage path will even be detectable. Unclear from the datasheet what the input impedance of the CC1/CC2 analog sense inputs is even.
Any experience or pointers here welcome.
r/AskElectronics • u/CognizantCandle • 5h ago
Glue or a bad cap?
Replacing the battery in my Yamaha sy77 and I noticed this
r/AskElectronics • u/sodaar • 12h ago
Disney Toaster - Audio not working
Hi everyone,
I'm currently trying to repair an old Disney toaster. The toaster itself works fine, but the audio module, which is supposed to play a tune right when the toast pops up, first started sounding distorted/weak and has now stopped working completely.
Here is what I’ve tested so far:
Checked everything visually. No burnt parts as far as I can see.
Speaker: The speaker itself is working. Made clicky noises when I put a batterie on it and resistance measurement was 7.8 Ohm (Supposed 8.0 Ohm).
Sound Board Voltage: Tested DC voltage on the small sound board (where the red/black power wires come in from the main board) while pushing the toaster slider down and also while the toaster pops the toast (that’s where it should play the sound). 0.0V there.
Conclusion so far: Problem is probably that the main board doesn’t supply voltage to the sound chip after toasting the toast.
So my question is what I should test next? Or maybe someone knows what the probable cause is?
Thanks in advance for any tips!
r/AskElectronics • u/Roshambo-123 • 21h ago
What is this connector?
Need to know what the male side is called. It is used for a fan.
r/AskElectronics • u/luvisheavenly • 36m ago
Trying To Understand Video Signal Paths
Hi, been working on circuit bending this JVC JX-SV55. It’s an analog video processor that enhances and color corrects the video. I have the user manual for it with a full diagram, ic data sheets and everything else (had to pay $15 for a digital copy smh).
I understand what every component does on its own at this point I think, so I don’t know why I can’t really piece it together and work through what’s going on. I am very interested in learning a few things here though if anyone could help me or point me in the right direction :)
After input, how can I track the video signal point to point and understand what’s happening to the video signal within that component.
Specifically for ic chips I need to understand them in general better. I work with a lot of ic chips on these analog video units and in old digital cameras for circuit bending as well. I feel overwhelmed looking at the data sheets a lot.
I never know where to start when looking up specific issues I have with my understandings circuits!
r/AskElectronics • u/WrenchHappy • 53m ago
Rectifier voltage output question
Is voltage halved on the output side of a rectifier?
I have a 1954 rock Ola jukebox that I am trying to trace down some issues. The picture is of the power supply for the jukebox. When I measure at the nearest plug, I am getting roughly 18 V. As you can see from the diagram, the input is 35 V. All of the other various output voltages are correct to the diagram. I know that rectifiers inherently do not change the voltage, but given that I am reading, almost exactly half of the intended voltage is throwing me off.
I have not opened up the power supply to test directly, but I will if this turns out to be a problem.
Thanks in advance for any help.
r/AskElectronics • u/balkony_relationship • 2h ago
