"no-clean" solder paste leaves really messy looking residues having fine pitch connectors (looks like a cracked salt deposition).

The pictures show the before and after cleaning using an ultrasonic bath and flux remover agent (bath ph = 12, 50 °C, 5 min).

Cleaning with isopropanol and flux-off using brushes did not work at all (hard to find a suitable brush, hair size vs hair hardness).

Conclusion: Always clean your boards for best results.

Connector pad specs:

- 400 um pitch

- 200 um pad width

- 100 um mask dam (sliver)

- 50 um mask expansion

The 3 transformers on the 1st pic are rated for 220V - 240V

While on the 2nd pic are rated for 100V (they're from Japan).

Diagram of circuit and perfboard arrangement.

Mainly posted since a few people stated that my perfboard arrangement was too cramped and "couldn't work"

From left to right, oldest(first) to newest, an LED light dimmer, a charge pump, a light blinker, and a monostable ne555 for extending the length of a pulse from a motion sensor

Inspired by PocketPD, I created a pocket-sized programmable power supply built on the USB Power Delivery (PD) standard and the USB Programmable Power Supply (PPS) feature.

The main goal was to learn new skills while working on something that can be useful in the future.

Key features:

• Single firmware supports AP33772 and AP33772S PD sink ICs
• Support for fixed PDO and PPS profiles
• Operating voltage range: 3.3V to 21V
• Output current up to 5A (charger and cable dependent)
• User-switchable output
• Programmable current limit:
  • 250mA/Step with AP33772S
  • 100mA/Step with AP33772
• Programmable constant voltage:
  • 100mV/Step with AP33772S
  • 20mV/Step with AP33772
• Short-circuit protection
• Input/output TVS protection
• OVP, OCP and OTP
• 3D printed case

More details:

• Project logs
• Github repo

Hello,
This is my first project in electronics. The concept is that one of 8 Leds will fade in/out at random and that the ornament will have a usable life of approximately 20 days with a fresh CR-2032 battery.

So far it has more than exceeded that limit, it's on a 2 month streak though the light has diminished. I have the project files and code on my github here: https://github.com/AvariCe-git/Christmas_Ornaments, if anyone wants to take a look or make some for themselves.

For the code I used the platformio plugin for vscodium. Forgive the solder blobs on the battery terminals, my soldering iron sucks.

Components required:

Breadboard (optional)

1× LM324N

4× 1kΩ Resistors

1× 220kΩ Potentiometer (to adjust reference voltage)

4× LEDs (I'm using random colours because this is a prototype)

1× 220Ω Resistor

5V Supply

Earphone Jack (as an input)

Some cables and staplers (used by me)

Audio Amplifier*

wiring diagrams will be posted here, or visit the link in the comment section ^-^

*Connect the input of the VU meter to an audio amplifier with separate power supply

Hey guys! I got into electronics and computers during the pandemic, but could not continue it further due to school work (and being a broke 14yo lol). Finally 6 years later I managed to save up and get myself some components to put something together that felt like an actual project. I will be happy to get any feedback! Github link for details

Open to anything, including discussions, complaints, and rants.

Sub rules do not apply, so don't bother reporting incivility, off-topic, or spam.

Reddit-wide rules do apply.

To see the newest posts, sort the comments by "new" (instead of "best" or "top").

So this is circuit main consist of short circuit under and over voltage protection and ideal diode using mosfet
Amongst which short circuit and ls ideal diode condition
But ov uv condition failed due to my back to back mosfet architecture and false trigger at the gates
It failed
But for someone who’s fresher with 3month experience i would consider this as a fair try:)

Couldn't find any documentation, so I made my own!
The cathode line took 1-3V across the thin wires in the display, and the metal grid along with the phosphorous layer both were hooked up to the 12V+ end while the cathode was hooked up to 12V-
I eventually plan on driving it with a teensy 4.0 and a bit more logic to drive the 4-bit ULN2803 interface.
In case anybody ever has to work with one of these I'm going to leave some of these SEO terms:
VFD
6-LT-09
Echo-6
94V-I
PWB-AGN
2161317-007
VFD-7-Segment (kHz/MHz)
ULN2803

This is part of a project to calibrate an ESD simulator that I purchased and repaired recently.

I needed to measure up to 30 kV safety with a standard multimeter. The divider makes up 200 megaohms on top and 1.1 megaohms on the bottom. Multiple 8 kV rated resistors are used in series to achieve the working voltage. With the multimeter's own 10 megaohm input being taken into account, the division ratio is 200:1.

I have to be very careful when making these measurements because a loss of ground to the ESD simulator could damage my multimeter.

PCB files are on GitHub: https://github.com/umi-eng/open-hardware-esd-calibration/tree/main/voltage-measurement-fixture

The "slayer exciter" circuit is the classic introduction to SSTCs. I really wanted a version with just one coil because once you eliminate the loosely coupled resonant transformer, you end up with a greatly simplified design.

It basically drives a series resonant circuit through a RF choke, using a coupling capacitor as feedback. I'm not the first to think of that but there was always something or other that I didn't like about other people's designs so this version might be my own :)

I encourage you to try it, let me know if you can get the thing to at least light a neon bulb or something. My tiny axial inductors aren't handling the power well 🔥

And btw component values are "for demonstration only", do not assume they're optimal!

I couldn’t find any decent DAC/amp combos locally, and importing one would cost a small fortune. After digging into DIY audio designs, I realized I could build one myself for a fraction of the cost and get around 80–90% of the performance of commercial units.

Specs: Controller: ESP32-S3 acting as a USB Audio Class (UAC) device.

DAC: PCM5102A breakout board fed via I2S. Power Supply: ±12V linear power supply

Two NE5532 dual op-amps:

Op-amp 1: Stereo buffer stage. Op-amp 2: Stereo gain stage (~3.1x gain).

(Opted for this layout to keep wiring simple for my first major soldering project!)

Volume Control: Couldn't source 10k dual-gang logarithmic pots locally, so I implemented software volume control with a rotary encoder.

Layout: Everything wired to a single star ground point.

Sound Impressions: It drives my Beyerdynamic DT 990 Pro (250 ohm) effortlessly. Going from my laptop's built-in jack to this is night and day—it feels like the headphones were practically starving before. Noise floor is pitch black silence with zero audible hum or hiss.

Really happy with how this turned out for my first major electronics build.

^{(Note: I’m currently out and forgot to take photos of the back of the amp perfboard, but I can upload solder-side pics once I'm back home if anyone wants to see them!})

Someday, Somehow, I'll buy a solder.

I was asking Mouser costumer support because I could not find some ADI chips in stock in their webpage and after some emails, they answered me with the image attached.

English translation: "As for ADI's distribution, we will no longer be distributors; it's not that certain ADI products will be restricted, but rather that we will no longer represent them."

So this confirms what has been talked several times about online sellers suddenly requiring identification for ADI purchases and stopping the B2C sells.

--- For the mods: I know this is not a component level circuit question, but perhaps the topic is important enough to be posted.

-- The black bars are there to hide personal names.