Why doesn't the MOSFET gate voltage reach its peak instantly? Is it because the gate behaves like a capacitor that requires charging time, and how does the magnitude of the charging current affect this speed?

Took apart my series x controller to change the joysticks to tmr ones I had bought because the factory ones started to drift. Not sure how this resistor came off, might have been bumped or something, but it definitely was not heated up.

EDIT: I meant resistor

I’m looking into getting one of these hot air stations but can’t really decide…

1. Atten 862, seems to be well liked by users of this sub reddit and other forums. Cheap and reliable but lacking in some features. Most comparable to Quick 861 (which seems unavailable everywhere).

2. Quick K8, I can’t really find any information on this station but figured if it was an actual Quick brand product it may be of decent quality for its price.

3. Sugon 8620DX, seems like an Atten/Quick tier station, pretty basic features and decent build quality.

4 & 5 Sugon 8630Pro and Sugon 8650Pro they both seem to be middle to higher end models, the main draw for me is the channel selection on the grips and the cooling function on the grip.

I’m just looking for suggestions or if anyone has experience with any of these. Going off what I’ve seen I’m leaning more towards the Atten because it seems to be pretty commonly used compared to the others. My use case would primarily be console repair so I’m thinking SMD components and things like usb port replacements etc. Probably won’t be a daily driven piece of equipment.

Any help in pointing me towards a decision would be much appreciated, thanks!

First of all, sorry for the bad diagram, couldn't find where to make it

Well the thing is im making a sprinkler system for my home, the blue M are solenoid valves and the red one is A1 and A2 of a contactor that turns on the water pump. Im using a 220v to 24v transformer and the relays are wifi actuated. The thing is that if I activate relay 1 to open solenoid 1 and turn on the pump i will retrofeed solenoid 2 too and don't know how to solve it. The thing is i need that when a valve is open the motor needs to start running, hope some of you can help

Hello, I recently spilled little bit of water on my keyboard. I just flipped it and shook it and continue using it since the keyboard advertised itself as waterproof. Then 10 minutes later it stopped working. When I opened the keyboard this is what I saw. I cleaned it with ISO and brush and tried it again but no luck. Do you guys think this is fixable? Thank you.

Hi I have a Jetson Orin AGX 64 GB.

Trying to find an adaptor board to two different modelled cameras that use FFC CSI-2 connectors. Would any of these work?

1. ⁠https://www.wdlsystems.com/alliedvision19616
   
2. ⁠https://www.arducam.com/product/arducam-imx219-multi-camera-kit-for-the-nvidia-jetson-agx-orin/

My concern with Allied Vision is that the driver API may not be around still and that it may only work with Allied Vision Cameras.

My concern with the Arducam board is that it only lets me use one of the same kind of camera (ex. Only 6 IMX 219s or only 6 IMX 548s)

Any help on figuring this out would be wonderfully appreciated because even if the ports are compatible I’m not sure how much of a pain the software side would be.

My engineering team and our integrators are fairly new to CAN communication, but we have to send and receive CAN messages for our new product. We used our long-time-trusted system integrators to build us a test bench, who are also new to CAN bus.

We can't send or receive CAN messages on our test bench, but our programmers managed to communicate via CAN with the same devices in a lab. We both use PEAK USB to CAN adapters, two 120 ohm termination resistors, the exact same custom PC program (LabVIEW), and both PEAK devices have a solid LED that indicate a successful connection to the installed PC drivers. The only difference is that our programmers used a twisted cable, our test bench integrators did not.

What I've verified so far on the test bench:

• CAN high and low lines not swapped
• Measured 120 ohm resistance on both ends of the CAN bus
  • 60 ohm across the whole system, 2x 120 ohm in parallel
• Measured 0 ohm on both CAN high and low lines all the way from USB adapter to product connector (~2m total length)
• Correct pins on both DB9 CAN adapter and product connector

I'm starting to suspect the non-twisted cable as the culprit. It would be very difficult to replace because the cables are routed deep inside the test bench fixture and very hard to reach.

Is there something else I could be missing as to why we can't communicate via CAN? TIA!

So I bought this RCA Bluetooth receiver 5v-12v and I am trying to connect it to my old cassette radios power and then leave the jacks hanging out the back for a simple Bluetooth mod. But I am having issues when testing it there is feedback noise in the speakers once powered on.

Outside battery it works fine obviously. If I leave the rca jacks off I can connect power to the receiver as long as I ground it in certain spots and it’s quiet, but once I connect the rca inputs the feedback starts. If I have the rca jacks up plugged in it will turn on with only the positive wire but the feedback is loud, and then connecting negative to a ground it quiets it.

I am very new to electronics, but I wanna know if I am just missing something or if it’s just how the receiver I bought works. Please go easy on me.

Accidentally dropped it and it opened, not sure which parts go where, trying to avoid messing with it too much not to snap the wires.

Was just trying to check the batteries cause it wasn't making the sound it's supposed to.

Hello good people of reddit

I am creating a Charge Sensitive Amplifier and have simulated and ordered the following PCB

I tested the circuit but was getting nothing but noise, even with a small source (Amerikium), although when i shined light on the diode it reacted and produced square waves.

Following these tests, i tried many different things and i settled down on this circuit

Now i the output of my second op amp is oscillating and then gets pulled to -2.5V. interesting thing to note is that the non inverting input is at 0VDC while the inverting is -0.025VDC (negative!). Note i didnt order a new pcb and just added them on top of the previous pcb (with solder bridges) since i dont know what the problem is yet.

The simulations run well, even with noisy voltages, so i dont think its that. could it be paracitic capacitances? i use the LTC6268 that is stable, not the -10. Any ideas on what to try?

EDIT:

Note that the weird think on top of the first op amp is the HPF

I have a Lenovo Legion 5 15ARH05 laptop in critical condition and I'm fighting for its life.
Its keyboard power cable shorted to GND and killed something on the motherboard that I am investigating after.

I found a blown chip close to the Audio Jack and USB port.
After I desoldered that chip, the laptop showed more signs of life, but the fans stopped working and still not POSTing.

I suppose there is a fan test that now fails and prevents POSTing, so I need that chip back.

It is a DFN-14 chip with unconfirmed purpose, but highly likely a fan control chip.
Pin 8 is VDD, pin 3, 5, 11 was shorted to GND.
The motherboard IDs it as UX2, whatever that means.
Its number is unreadable, but maybe you guys recognise it.
Can you figure out the partnumber please?

Hi everyone, I have a problem and I hope this is the right subreddit.

A few days ago my radio stopped working. I tried opening it up and found that two resistors, “R41” and “R42,” had burned out, as you can see in the photo.

I tried checking their value with a multimeter, but they read as completely dead. Now I’d like to replace them, but I have no idea what their value is, and the burn damage makes it impossible to read the printed markings to find out.

The radio is a Panasonic SA-UX102, and the SMPS board shown in the photo is an “N0AE1GN00001.”
How could I figure out what resistors these are? I can’t find a decent-quality photo anywhere online, nor a datasheet for that component.

Sorry in advance if I’ve written anything poorly, but I only partially translated the text myself.

So it had water damage at some point but no visible issues.

With power supplied the screen does not work, nor the buttons etc.

I checked with a multimeter the main plug fuse, fuse F1 on the ac board and a few traces on the lv board. The fuses showed connection, and the random trace check showed no short circuit.

I am unsure what else to check, I have a soldering iron and multimeter only.

I'm trying to build a bass preamp with several filters in it: I've attached my SVF design for one of the LPFs and it simulates how I want (I'm pulling from VLP3). What I would like to do is use a stacked potentiometer, with one controlling 2 reverse log gangs for the frequency (Rf_P1 and Rf_P2), and the other shaft controlling two linear gangs for the Q and compensating gain (RQ_P1 and RG_P1 respectively).

The following link has something like what I want to build, however without the compensating gain so increasing the Q will boost the gain as well: https://www.underhillbass.com/product-page/fv-filter

I have a few questions that hopefully someone here can help with:

1. Firstly, is this circuit insane/poorly designed? This is all self-taught/researched so I'd appreciate a sense check or pointers towards something better.

2. Such 4 gang, concentric shaft potentiometers don't seem to be on the market without direct factory commissioning. Does anyone have any tips there?

3. The above link uses a 3 gang (2 and 1) potentiometer. Even finding these is difficult. If I can't build a gain compensating circuit I may replicate this, but does anyone have tips on where such 3 gang concentric pots might be available?

So I am using LIS2MDL as my magnetometer. I am making a device which uses the magnetometer for metal detection, and the device is placed outdoors in harsh environmental conditions (like rain, heat and all). Obviously, it is placed in an enclosure.

Speaking in rough terms, I have created a program for this device where it does calibration of the surrounding environment with no metal around the device. After calibration, the device detects metal based on the changes in the magnetometer readings.

I have placed the device outside, and whenever metal goes over the device, it detects it properly for say 2-3 days. But then it starts hallucinating on its own, even when no metal is present, it says metal is present.

If I re calibrate it, it starts working properly again.

So I wanted to understand: is it something with the LIS2MDL? Could environmental conditions like heat, rain, humidity, etc. cause the magnetometer readings to change or drift over time?

Because the calibration and detection functions are just mathematical operations, and for the first 2-3 days it works flawlessly, but then its performance deteriorates.

Hi fellas,

I am currently designing a basic USB 2.0 programming interface for STM32U575.

It will be used to program the MCU without needing any STlink programmer anywhere where it is necessary for updates etc.

So I was wondering if using Bidirectional ESD diode makes more sense than using unidirectional on CC pins where they are not controlled by any IC.

Reason behind that during hot-plugging small negative transients would be stopped on the cable / connector due to the diode at least up to -6, -7 volts and keeps the ground clean.

Other than that there will be 1 less Part in the BOM if I use the same part as on the data lines which is also another small gain.

Am I missing something ?

Or is it even necessary or worth putting esd on CC lines if they are connected through 5.1k resistors to the ground? Resistors will filter lot of transients already.

Thanks in advance.

hey so you guys are probably my last shot. i have a device im repairing where i lost one of the rotary knobs from. could you help me identify it. or maybe give another option on how to solve this?

really need you guys here

After many failed attempts at repairing/upgrading the original PCB, I've come to the conclusion that there are to many degraded tracks and solder points. Id like to print a replica of the original board so after etching and drilling its an easy component transfer. What I'm having trouble with is getting from a pdf.schematic to a kicad.pcb that I can print. Is there a shortcut or anyone willing to help or a knudge in the right direction

Hi, I'm designing a custom led head light for dental surgery. A simple RCD24 circuit with a thermistor temperature regulation and a potentiometer. I originally planned to use a plain 18V wall DC adapter, but it might be a bit complicated in a surgery room.

I've got a few Makita 18V 5Ah batteries and thinking why not to use one of those. The problem is, they don't have an integrated undervoltage protection.

There's a quite convenient way to power off LEDs by sending 4-5V to an analogue dimming pin of a RCD24 (0V - 100% output; 4.35-max5V - 0% output). I just can't figure out how to send 5V to the pin, when input voltage drops under 15V.

I've googled a bit and found out some solution with a comparater circuit lm393, but have no experience nor proper knowledge to the matter.

Thanks for any advice!

hi there,

I'm working on a guitar pedal with some LED indicators - a red and a green one are poking directly through the front panel (3mm THT) and a blue one (SMD) is below an MX Cherry switch that's placed 1cm below my case.

Now, GPT says 100mcd LEDs are too bright for the THTs but just right for the Cherry switches.
Gemini says 1500mcd LEDs are just right for the THTs, but they need to be diffused.
The internet is oddly quiet about this so I have no proper reference or whatsoever. How do I know which brightness will be just right?

Another problem is that Kingbright (I'm open for other manufacturer suggestions) mostly offers 570nm light which is allegedly very yellow (557nm). Their red ones I found were also very orange (617nm is best I can do).
Is it that the nm to rgb converters are not accurate and it will actually be green and red, or should I look for a different LED?

my current picks: green tht, red tht, blue smd

any help is greatly appreciated.

I have a Sony PVM 1953 that has some rectifier diodes that are shorted or not functioning correctly.

Here’s the list:

2x 10E-2
2x RH-1A
1x ERC38-06 (V19G)

I think a 1N4006 should work to replace the 10E-2, but I can’t find much about the RH-1A. The V19G was also hard to find much info on. It has a unique shape which leads me to believe it was made by Hitachi (the attached photo matches the shape and markings).

Any help is greatly appreciated!

Hey everyone,

​I was working on a mod on this board \[ALLWINNER T113 Embedded board\] and soldered a couple of wires to test some signals. The tests worked as expected, but while desoldering and cleaning up, I accidentally ripped a pad off the board.

​Ever since, the board still powers on and has display, but part of its communication functions died completely. Looking closely under the microscope, the ripped pad sits right beside the TXD / RXD silkscreen markings, so I strongly suspect this broken trace interrupted part of the serial communication line.

​I have never done micro-soldering or PCB trace repair before, so I’m looking for experienced eyes on how to properly assess this:

​Could this ripped pad definitively cause the lost communication? Given the failure symptoms?

​Where did this trace originally go? Under the microscope, I carefully scraped some of the solder mask nearby to reveal the copper traces, but being a multi-layer PCB, I want to make sure I’m reading the trace path correctly and not confusing surface traces with internal ground/power planes.

​What is the safest way to restore the connection? Should I try soldering a jumper wire directly onto the scraped trace, or is it safer to trace continuity with a multimeter to an adjacent via/component pin and jump from there?

​Microscope photos of the ripped pad, adjacent traces, and exposed copper are attached. Any insights on the likely trace path and practical tips for bridging this safely without ruining the board would be greatly appreciated!

I recently got a Dell UltraSharp U3223QE 32” 4K monitor that was going to be thrown away at work. Everything seems to work normally except for a large dim area along the right side of the display, which gets noticeably worse toward the bottom-right corner.

I tested it using solid white, red, green, and blue screens. The image and colors are still visible in the affected area, but that section is significantly darker. The shape/location of the dark area stays basically the same with every color.
From what I’ve been able to find, I’m wondering if this could be a failing LED backlight/LED strip, backlight driver, or possibly something with the diffuser/light guide rather than the LCD panel itself.

I’m not experienced with monitor repair, and because this is a 32” panel I’d rather pay someone who knows what they’re doing than risk cracking it myself.
Does this look like a repairable backlight problem? And roughly what would you expect a repair shop to charge?

I’d be comfortable spending around 150-200 to have it professionally repaired if that’s realistic. I got the monitor for free, so I’m mainly trying to determine whether repairing it makes sense.

I’ve attached pictures of the monitor displaying solid colors so you can see the affected area.
Thanks!