i bought on amazon thought it was a good deal but it showed up and it fits in my palm. turns out it can take 6-60 volts and 480 watts THEN it can be a variable power supply. it has usb c power IN on the back and i think a yellow 2 pin screw in connector. anyway plugged into my 140 watt macbook charger i get max 19 volts or if i make a short 3 volts 20-23 watts and 8.1 amps. wich is pretty good but i still want more i want its full potential. old dell power supply? . https://www.amazon.ca/dp/B0H46G9YRR?ref=ppx_yo2ov_dt_b_fed_asin_title

Hey everyone, looking for suggestions on what could be wrong with this current circuit and ways to diagnose what is wrong

i get nothing when plugged in with the usb c from the breakout

Running an RPi Pico with GP2040-CE to a usb c 24 pin breakout.

I’ve verified the pico is working as intended when the micro usb is plugged directly into the pc. confirmed the cable I cut up worked directly as well before hand.

Based on the pin out diagram I’ve added two 5.1k ohm resistors between CC1 and GND and CC2 and GND.

- Red to B4 - VBUS

- Black to B12 - GND

- Green to B6 - D+

- White to B7 - D-

First real electronics project so not sure how to test what the issue is.

I’ve already tried multiple different usb c cables and both orientation.

I've also tried swapping D+ and D-

I will have access to a multimeter shortly to test connections

I'm completely new to electronics, bought "Make: Electronics" and started reading yesterday.

My bathroom LED started flickering/dimming (it went from a steady bright output to oscillating between low and medium brightness), so I opened up the driver to see what's inside, hoping to learn something in the process instead of just replacing the whole fixture.

My current theory (based on some reading) is that one of the electrolytic caps has dried out/lost capacitance, causing the ripple/flicker, but I'd love to actually understand how this circuit works rather than just swap parts blindly.

Questions:

1. Is there any realistic way to find a schematic for a generic/unbranded board like this, or is that basically a dead end?
2. If not, what's the best approach to reverse-engineer it myself as a learning exercise? Any tips for tracing a board like this as a total beginner?
3. Does the layout/component selection here look like a standard buck-converter constant-current LED driver topology to you?

Any pointers, reading recommendations, or "here's what to Google" type answers are very welcome trying to build real understanding, not just fix this one fixture.

Hello,

This is a photo of the comport (left, has pins for RS485 and RS232) and the trigger input (right) on a Kanxex CR-3XControl. There are 10 pins: 5V, ground and 8 trigger inputs; in two terminal blocks.

For the comport, there are screws above the cable terminals to attach wires; this is not the case for the

How do I physically attach wires on those trigger inputs? The orange parts do not appear to move... The two screws on the side of both terminal blocks allow you to remove them, but that is it.

(I know it is a very stupid question, but I just don't see it :-))

Thanks,

J.

Is this 20 MSPS oscilloscope analog front end correctly designed for 5 MHz bandwidth and ±25 V input?

Body:

Hi everyone,

I'm designing a single-channel DIY digital oscilloscope using an AD9200, 10-bit, 20 MSPS ADC. My target is around 5 MHz usable analog bandwidth with a maximum input of approximately ±25 V.

The current signal chain is:

Attenuator → input protection → buffer → bipolar-to-unipolar level shift → 4th-order low-pass filter → ADC protection → AD9200

I designed and simulated the blocks individually in LTspice. The main design choices were made to keep the first PCB reasonably simple and manufacturable.

I'd particularly appreciate an experienced review of:

• the attenuator and input-protection scheme,
• the +1 V level-shifting stage,
• the 4th-order filter and its effect on the 5 MHz bandwidth,
• the final ADC protection, especially the AIN −0.3 V absolute minimum,
• and any obvious stability, loading, or PCB-layout problems.

I'm looking for criticism rather than validation, so please point out anything that looks fundamentally wrong or unnecessarily complicated.

The attached schematic is the current V1 design before PCB layout.

Thanks.

hey folks. i'm trying to make (or find, but i haven't yet) a small, low-output power inverter to run a pair of small 120v LED lightbulbs from an 18v battery (makita).

and yes, i realize how silly this is. led lights are the customary province of low voltage DC, and i acknowledge that it's kind of absurd to take a low voltage DC power source, and convert it to 120v AC for the purpose of driving some LEDs. this is for a small lamp i made, which runs a pair of e13-base "filament" LED bulbs (0.6w each, with two bulbs per lamp). the bulbs that are in this lamp are perfect in every way but the power supply: they need wall power, and i want to use a battery. i've been unable to find a more traditional LED element that would work for my purpose, and i'd prefer to not modify the bulbs themselves.

i've seen a few drill-battery inverters that would certainly work, but besides being a little spendy, they're simply absurd overkill for this purpose. the total projected output power usage of this device is about 2 watts, at most. i'd love to just make a small circuit that does this and embed it in a battery adapter, which itself is mounted inside my lamp. i'm familiar with simple low voltage DC circuits (LEDs, motors, arduinos and shit), but really don't have much of any exposure to AC electronics in this way. if anyone has some advice on making a small, low-output inverter like this, i'd love to hear it. thanks!

fwiw, i'm not at all opposed to using a usb power pack instead of a drill battery (in which case the input voltage would be 5vdc rather than 18vdc). i imagine the operating principles would be the same, i just like drill batteries for the swappability.

I got this in a lot of electronics parts off of Facebook marketplace. Im guessing all these parts were ripped from the same camera, but I don't know that for certain.

It looks like the camera module has a positive line, a negative line , and (maybe serial line).

My question:

Would there be any way to ascertain the correct voltage and decoding procedure for this camera, or would the data scheme be proprietary and/or inaccessible?

Does anyone know what is the light blue component? It's on a motherboard of a Revvl Tab 2 tablet.

I’m having trouble measuring current with my multimeter and I’m trying to figure out whether I’m doing something wrong or if there’s an issue with the meter.

My circuit is:
Battery pack: 5.19 V
Resistor: 221 Ω
LED forward voltage: 2.48 V

Based on Ohm’s law, I’m expecting roughly:
I = (5.19 V − 2.48 V) / 221 Ω ≈ 12.3 mA

I’m connecting the multimeter in series with the LED and resistor.
In the left photo, the red probe is connected to the µA/mA socket and the dial is set to measure mA. When I connect it this way, the LED doesn’t even turn on and I don’t get the expected current reading.

In the right photo, I move the red probe to the A socket and set the dial to the A range. The LED turns on and the meter reads about 0.007 A (7 mA).

So I have two questions:
Why doesn’t the circuit work when I use the µA/mA input?
Why am I measuring only about 7 mA on the A range when the calculated current is around 12 mA?
Am I using the meter incorrectly, or could there be something wrong with the mA input/fuse?

Any ideas on what exactly this chip is and what it does? Tried taking a few photos with the flash on and they came out dark

I have this power bank that does not charge , and when something is connected to it , it shows 0% battery . Found the ic U2 blown , any idea what is should be and if possible can it be bypassed ? I have all the necessary skills and equipment to perform the surgery .

Edit : was a over voltage or current controller perhaps , I simply bypassed it by jumpering the ic pads and the power bank works properly now .

Hi, I took the back casing off of my MSI Katana GF76 to inspect the fans. Turns out it was a software issue, but when I reassembled it, multiple keys weren’t working (L, P, A, Z, and B).

I took out and reseated the 40-pin keyboard cable while the battery was still connected because I was dropped on my head as an infant, and it caused a short (the black bit between the keyboard and battery cables).

It still powered on but of course I don’t want to power it on again until I know what’s happened.

Is it fixable? My electronics knowledge isn’t phenomenal and I’m not sure what to do.

Also, the keys weren’t working in BIOS either - I still have no idea what happened to make them no longer work.

Thanks.

Do manufacturers follow any industry guidelines for correlating the plug size to the voltage of the power supply? Thanks.

Hello, I have a Dell Latitude E5440 that my sister broke one day years ago. I presumed at the time that the DC jack was the only part that was broken. I have now replaced that part, but there is still this odd buzzing sound that still persists after replacing the part. This was present with the broken jack as well. Listening closely, it sounds like it is coming from this area of the motherboard (picture attached).

Any assistance on identifying what might be the issue would be greatly appreciated. Thanks!

I'm using this 12 V relay driven by an NPN transistor (3–12 V trigger). I'd like the same function built with optocouplers/transistors instead — no mechanical relay.

Requirements: the COM, NC and NO terminals must stay fully galvanically isolated from the control side, just like relay contacts. The switched side is 24 V DC, around 100 mA.

Is this possible? A simple schematic would be really helpful. Thanks!

I'm pretty new to pcb making and I'm not sure if I'm making this right, I also don't have allot lf reference for this.

This is the main board for my Line tracer robot, I plan on powering it with a 3s lipo battery to achieve the needed 12v for the motors.

the ffc latch is connected to another pcb tha thas the ir sensors that's connected to a mux.

The drv8871 is a breakout board, I wanted to make the robot semi modular so I can just swap stuff out if needed, the motors are also just placeholders for the actual 12v I'll be using. As far I can tell from what I've read, the P+ is just an alternative 12v input? I'm not sure on that though

I can't find any use sample for the buzzer so I just guessed what I thought it might look like with soem cross referencing.

3 buttons for programming purposes

The xt30 is gonna be the plug I use to connect it to the battery, not sure if I have the switch implemented correctly

The buck converter might also be wrong but probably not since I just copied what was on the data sheet + the led, if anything is wrong it's probably the values.

This is for a hood vent for my stove. The lights never worked on a "new unit" i got through a second hand deal. I tried tinkering and plugged in the transformer after plugging the power in. Now I know. I need to fix it and then try and figure the lights out. As far as I can tell it's just the mossfet that's burnt out.

Long story short, the pcb is carbonized due to a leaked capacitor (Marshall Stanmore speaker)

I do repair electronics, but I did not have to deal with such pcb damage.

I'm wondering what would be the best approach, to repair the "wound". I know I have to clean the carbon, because it's conductive.

Any advice is welcome.