Reddit:Electronics

im waiting for it to arrive and i want to know how bad it is for the first time, its electrically correct but it looks kinda bad with the overlapping text and some other things.

the pcb is double sided and i dont have a photo of the other side.

Someone please help. With switch off I have 120v on the black wire at the 6 0’clock position. With switch on there is still 120v at the black but no power anywhere else. I have already checked the switch and it is good, what am I missing?

Rainy Sunday. So I decided to build a test jig for SMD parts. That's a 0402 resistor in the image.

What if somebody built an entire calculator using only transistors, resistors, buttons and LEDs. No ICs, no logic gates, no arrays, nothing but pure smd transistors. A calculator with 4 7-segment displays (1+1 for the two input numbers, 2 for the result), 10 inputtable numbers (0-9) and 4 operations (+,-,*,/). Everything would be driven by transistors, including the displays. According to ChatGPT (very reliable, I know), it would take around 3000 components to build such a device. Difficult to make? Yes. Cool to look at? Yes!

My grandparents got this pinball machine in the mid 60s. There was a mechanical spinner that would register and record a highlighted letter if you hit a certain thing when it was lit up. It used a mechanical spinning device that broke, so my grandfather built the circuit board as a sort of logic puzzle after taking apart the mechanical device and figuring out what it needed. don’t know anything about electronics, but I thought y’all might be interested

Do you know any high school students (or younger) who are interested in learning more about electronics and PCB making for free ?

If so, check out two these two 100% free programs from HackClub:

• The Bin is for students who want to build projects with Arduino / RP2040 and assorted peripherals. You design and verify your circuit in the amazing WokWi simulator , and we'll send you all the parts to build your design. You can do it again and again.. and it's 100% free !
• Want to go further and build your own customized PCBs ? If so, check out project OnBoard. Create your design in the PCB tool of your choice (EasyEDA, KiCad, etc).. Submit your schematic and PCB and we'll give you a $100 grant to build your design at a PCB manufacturer . You can build your own bare boards, or have them completely assembled. Your choice !

Join the hundereds of students worldwide who are building cool stuff and falling in love with electonics!

John Cohn PhD
BETA Team Member, IBM Fellow Emeritus and Hackclub Maker

Ps. Here'sn example of the kind of boards students are making:

https://jams.hackclub.com/batch/sparkletilt-pcb

SparkleTilt: a light up level designed by Karmanyaah H

Thought I'd challenge myself and depart from the tired methods of buying miniscule op-amps and smack something together from spare parts, although I bought some decent-quality components from Mouser to build the final version lol

Took me about 2 hours to design and another 3 to fully work out.

This thing is run by an LC oscillator. From what I could gather, the inductor creates a high voltage at the junction between the 1K resistor and the collector of Q1, which is fed into a resistor-transistor inverter of sorts (Q2), and then run through a miller integrator (Q3). The result is this extremely clean triangle wave with only a small amount of frequency drift (I estimated about 1% over the course of an hour, but I attribute it to the half-dead battery I'm using). I won't pretend like I know every detail about how this thing works, but I honestly didn't expect it to run this well.

The schematic:

https://preview.redd.it/3vvprndwtn0d1.png?width=980&format=png&auto=webp&s=679033ea2042f039983cce1a75c19a79ab5f987a

The board:

https://preview.redd.it/qfygy19xtn0d1.png?width=1186&format=png&auto=webp&s=6ace4be47738739d2fc4a9b30768541593e20161

The result:

https://preview.redd.it/gs84nbaytn0d1.png?width=1142&format=png&auto=webp&s=d9aa86adcd16dab1e1c7a818e7858326984f4ead

Unfortunately space demands to be filled.

My wife groomed her and I thought of you guys and gals.