/diy/ - Do It Yourself

Thread let the smoke out:>>1937846

>I'm new to electronics. Where to get started?
It is an art/science of applying principles to requirements.
Find problem, learn principles, design and verify solution, build, test, post results, repeat.

>Project ideas:
http://adafruit.com
http://instructables.com/tag/type-id/category-technology/
http://makezine.com/category/electronics/
Don't ask, roll:
https://github.com/Rocheez/4chan-electronics-challenges/blob/master/list-of-challenges.png.png

>Principles (by increasing skill level):
Mims III, Getting Started in Electronics
Geier, How to Diagnose & Fix Everything Electronic
Kybett & Boysen, All New Electronics Self-Teaching Guide
Scherz & Monk, Practical Electronics for Inventors
Horowitz and Hill, The Art of Electronics

>Design/verification tools:
LTSpice
MicroCap
falstad.com/circuit/circuitjs.html
NI Multisim
CircuitLab
iCircuit for Macs
KiCAD (PCB layout software, v5+ recommended)
Logisim (Evolution)

>Components/equipment:
Mouser, Digi-Key, Arrow, Newark, LCSC (global)
RS Components (Europe)
eBay/AliExpress sellers, for component assortments/sample kits (caveat emptor)
Local independent electronics distributors
ladyada.net/library/procure/hobbyist.html

>Related YouTube channels:
mjlorton
w2aew
jkgamm041
eevblog
EcProjects
greatscottlab
Photonvids
sdgelectronics
BigClive

>Li+/LiPo batteries
Read this first:http://www.elteconline.com/download/pdf/SAFT-RIC-LI-ION-Safety-Recommendations.pdf

>I have junk, what do?
Shitcan it

>>1945420
>How did you determine that it was coming from your mains wiring?
I tore the amp down to everything but the power supply and it was still there. I even removed the rectifier tube and jumped the transformer out to an external diode rectifier and capacitor and still saw it.
Then I plugged in a scrap 48v transformer, again rectified and filtered it, and still measured the same noise. Smaller, because the voltage of the tranny was lower, but it was still there.
This isn't the first time I've seen it, either. It was never an issue before because it was easily rejected by voltage regulators so I just ignored the mystery until now.

I'm going to try flipping breakers tonight, after the rest of the building empties out. I suspect it's coming from outside the house, since the noise is so random I suspect it's being caused by load fluctuations elsewhere on the block.