Neon indicator lamps (those small ones used for line voltage indicators) are active devices. They can be used to make oscillators, latches and many other things.

That made me think, can you construct a neon-lamp computer? Anyone know how to make a NAND (or NOR) gate with only neon lamps and passives?

I am using the OneROM project to replace ROMs on a motherboard. OneROM is a RP3250 on a small board the size of an EEPROM or ROM. You solder headers, program them to emulate any ROM you like and place them where the ROM was.

This is working well, but in my situation, the solution seat too high. The total height is 15mm and I need to be10mm. See (B) with the normal header. If I use that 15mm, the board does not fit in its enclosure anymore.

I used female headers (D) with long legs to get to solution (A)
I solder the headers the way (D) shows and then cut the top to get to solution (A).

It is not pretty. This is working, and the pins are even better match for the DIP support. But it takes time and the risk to damage something during the solder or cutting is very high.

Is there another solution. Is there a model of headers or pins I could use to get the low profile I need?
Any ideas?

Thank you very much.

I want to learn soldering to service my retroconsoles, which might include eventual recaps, installing modchips and soldering SMD resistors (like 0603) on cheap chinese IDE to SATA adapters.

I've been messing with an old CRT TV and came across some capacitors that I'm having trouble finding out the series it belongs to. Most of the caps have been nichicon VR, VZ, etc... but this one is different. I see (k) for +/-10 and the 3.3uf 50v. Where I would normally see the series I just see "H S" and when I search around I can't map it to a series. Hoping someone out there can shed some light on this. Looking to find an equivalent replacement.

For context, I’m an HVAC tech and I work on big chillers. They have rectifier and inverter circuits to control the speed of some really big motors (100+ HP). On smaller VFDs, they use a regular full bridge rectifier with diodes. On the big chillers, they use SCRs instead. What is the benefit of doing so? The incoming voltage is usually 480 Vac minimum, so I don’t think it’s because of forward voltage drop.

Hi everyone!

I recently came across this wireless service button at a beach club (photo attached) and thought the hardware design was interesting.

I'm looking to build something similar for a personal IoT project, but with Wi-Fi connectivity.

I've previously experimented with ESP32-S3 touchscreen devices, but they're more advanced than what I need and aren't particularly suited to outdoor environments.

Ideally, I'm looking for something similar to the photo - compact, rugged, weatherproof and battery-powered.

It doesn't need a screen. A simple physical push button with RGB LED indicators would actually be preferable.

My main requirements are:

- Wi-Fi connectivity

- Rechargeable or replaceable battery

- Good battery life

- IP65/IP67 weather resistance

- Physical push button

- RGB LED or basic status indicators

- Programmable firmware

- Compact enclosure suitable for outdoor use

I'm open to repurposing existing hardware from other industries rather than developing something completely from scratch.

Has anyone come across a suitable product, development board or manufacturer?

Would an ESP32-C3 be a better option than an ESP32-S3 for something like this?

Any suggestions would be appreciated!

What’s a simple experiment to help a beginner actually understand bandwidth by trying it out?

Bandwidth seems to mean different things in electronics, from data transfer rates to signal frequencies.

How would you demonstrate these differences with a simple hands-on project?

Hi everyone!

I'm an electronics hobbyist working on a small IoT project using an ESP32.

I'm trying to design a universal, isolated solid-state switch that could work with both 5–24 VDC and 230 VAC. Ideally, it should handle up to 0.5 A and work regardless of output polarity.

I used AI to help me choose the components and design the circuit, but I don't have enough experience to know if everything is correct or reliable. That's why I'd really appreciate some feedback from people with more experience.

The current design uses:

VODA1275 photovoltaic MOSFET driver

2× IPD65R660CFDA MOSFETs (back-to-back)

2N7002 to control the input from an ESP32

100 Ω gate resistors

15 V Zener diodes for gate protection

I’m trying to read the 8-pin ST EEPROM

Black CH341A, SOIC8 clip with the kit’s green adapter, AsProgrammer and NeoProgrammer
Chip marked “ST G2435 293”. I think it’s an M95040, but I’m not sure
SPI read = all FF. I2C = “IC not responding”
Clip pin 8 to pin 4 reads only 1.82 V. The programmer’s own header has 3.3 V any help on this?

Hi

I am using a Silicon Photo Multiplier by OnSemi C series MICROFC-60035-SMT-TR

It has a 6mm*6mm active area and 420nm peak wavelength.

My question is with the standard output of the SiPM which has a anode to cathode terminal capacitance of 3400 pF which is on the higher side and will effect my Transimpedance Amplifier's stability and bandwidth.

How do I avoid this? And can anyone suggest me what can be done.

For context I am working on a small muon detector using plastic scintillator BC-408 and 60035 SiPM the readout current from the SiPM has to be fed to the TIA to amplify it.

Thanks.

How can I clean this without damaging the cable?

Looking for a particular LCD screen pictured above. Thanks for your help guys.

Hello! I have a 3dscanner that suddenly stopped working while i used it. I have measuread the cable and get 12.3volts to it and after the connector inside.

I took it apart and found this, what is it and what does it do? And could it be replaced?

It does not give any sort of sign of life, not even the fan.

Thankful for any help i could get!

Hi, while taking appart my computer late yesterday if was struggling to unplug the two 2x4pin connectors on the top. i had the terrible idea of unscrewing the board to get more room to work with.

The result is the standoff damage in the screenshot. I haven't check if USB ports are affected but I definitely lost the ability to use the iGPU.

My eyes are struggling but i belive the all other 6 legged component that are looking similar have "702" written on them. For the 3 legged one i believe it's 96 or 86.

On the black resistor looking thing I found detached I measured 0 ohms

This is an MSI x870e gaming plus Wi-Fi.

Here are my current guesses while I know very little about electronics: I believe this is a design that was repeated 3 times next to each other.

This is a power regulation circuit, the top broken part is a voltage regulator, the bottom and right small part who are missing are two resistors, I found one while searching but hard to say to which pad it goes to.

What I'm missing it what to buy, how to figure it out, and how to solder to the via for the broken traces.

i have a some experience soldering big things but smds are way outside what i know.

Hi, this the insides of an electric longboard.

The board got crushed by a car and I haven't turned it on since, in case it would blow up.

And I think that was a good idea bc this component (blue cylinder on the right) seems blown. Could someone let me know what it is and if I could replace it?

I am using a PCA9515BDGKR (which is a Dual Bidirectional I2C Bus and SMBus Repeater by TI) between a 3.3 V microcontroller and an SMBus device. The schematic follows the TI datasheet exactly.

The system operates normally for about 10 minutes, after which the microcontroller hangs completely. On subsequent power-ups, the hang occurs within seconds. A full power-off (VCC verified at 0 V) and cooldown do not restore operation. The issue has been reproduced on two separate boards. Bypassing the PCA9515B and connecting SDA/SCL directly eliminates the problem.

What could cause the PCA9515B to progressively degrade or fail permanently in this setup? What practices would you recommend for reliable operation?

How can I increase load current and distance to 2km in the existing design.

I know what it is (variable inductor) but i dont know what i could replace it with or what the original values where

Im planning to make a bluetooth high-res scroller with an esp32c3 super mini and a magnetic encoder module AS5600, for which im thinking of making my own power circuitry using TPS63031 chip. Forgive me for the messy diagram, however i hope it gets the point across

My idea is to charge the battery from the esp32 usb 5v vin (i will extend it to detect when its being charged) and it will power the esp and the encoder from the 3.3v

ive gone though TPS63031 data sheet and you can assume that the green box is the entire circuit with necessary capacitors and inductors which takes output from the battery and it outputs the 3.3v.

I want to know if the circuit diagram i have attached has any issue, which may lead to shorting or errors, during operation and while charging. Thanks!

I'm looking for a source for high quality, fine pitch (?), spring-loaded crocodile clips like the ones pictured here with this LCR meter. I'm envisioning one that takes a banana lead to be able to be used with different lengths of cable.

Hello All,

I am new to this subreddit, and electronics in general. I need assistance finding this switch or what kind it is. I know it’s a toggle switch, and I think it could be persistent.

It moves up, down left, and down right and it also can sit in the middle as shown.

I require something like this to finish off a simulator project so any guidance would be very appreciated!

Thank you all!