Chapter 23 - Circuits & Semiconductors #
When I was a kid I thought about circuits as being alive, like Cells at Work!, only little electrons going around busily keeping the heart of my toy working instead of anthropomorphic red blood cells working in the human body.
Now, as an adult - and a computer and electrical engineer at that - I still find this thought endearing. Though I’ve now come to see the physics and art of electronics to be even more beautiful when their true nature is really understood.
There’s a joke you’ll hear about those that work with these low level physics or that arrange logic gates to make full CPUs- that our job and passions boil down to teaching rocks to think.
So, let’s lean how to teach some rocks.
©Vega, made with Noisedeck
Show everything in a circuit sim, fix heading levels (this is a mess)
Possibly break up this chapter? Transistors, the opamp, etc alone may each justify their own chapters
That said, I don’t want to get to in the mud of transistor physics. I really want to focus on how/when/why to use what, not how they work as the physics is both pretty hard to grasp and not super useful. Still would like to mention that switching is what uses power and like process size things, but maybe not the chemistry or electron tunneling effects, at least not in great detail
Chapter 23.1 - Semiconductors #
TODO, looks very good briefly scrolling though it: https://lcamtuf.coredump.cx/electronics/
Digilent’s ‘Real Analog’ course looks okay too, and I might write this guide assuming their analog parts kit: https://learn.digilentinc.com/classroom/realanalog/
[TODO] pic of silicon bulb
P/N junctions, etc.
Diodes, the one way road #
A diode is a two-terminal electronic component that conducts current primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance in one direction, and high (ideally infinite) resistance in the other.
Diode page on Wikipedia (which is actually super good)
Alright, so in very basic terms, it’s a part that only lets current flow in one direction (idealy). A one-way road for current. If you put a sine wave in, you’ll get a sine-wave chopped in half out. Now, this assumes everything is ideal, as you’ll really get more like the top 40% of the wave out, but we’ll get to those details in a bit. For now, I recomend watching these videos:
zeener, normal, bipolar
- varistors , sparkgaps
- Leds - getting current both ways, LED safety
Diode Logic #
tubes and how they work
PNP V NPN #
tIGBT, Mosfets? #
Integrated Circuits #
Distortion pedal with all homemade semiconductors, only one external component (cap for AC coupling) pic.twitter.com/M7t3Gl1m5P— Sam Zeloof (@szeloof) July 6, 2020
Finally I learned how to do focus stacking with my macro (non-microscope) shots. 226 shots, 50µm camera shift per frame. Laowa 25mm F2.8@F4 on WeMacro rail. Stitched in Helicon Focus (pyramid, smoothing=1). 1 original photo for comparison. #WeMacro @laowa_lens #heliconfocus pic.twitter.com/yCdCIBXMRv— Zeptobars (@Zeptobars) March 12, 2019
555, OpAmp, 74-Series Logic #
Chapter 23.2 - Op-Amps & Filters #
Optical Electronics #
Crystal Oscillators #
Active Filters #
Audio Devices #
speakers, piezos, amps, mics and pickup patters
add motors, analog meters, various connection standards, radio, flex/pressure sense, grounding (chassis, digital, analog, ground planes, etc.), solar/photo reactive,
Relating AC and Music #
Relate back to things like ADSR, Distortion, Reverb / Echo, Decibels (audio), etc. Use VCV RACK
Chapter 23.3 - Safe Circuits #
Chapter 23.4 - Rare and Dangerous Componets #
- Tesla coils
- High voltage/current/hot/whatever
- Don’t pretend to be an electrician
- Don’t use ATX psus for dumb things
- Tubes, NOS parts, etc. - TODO: CRTs and Aquadag
Continued Reading: #
At this point I highly recommend ‘Practical Electronics for Inventors’ ISBN 978-1259587542, namely chapters 2-12, and 15-16. It’s a very large, detailed book that does its best to keep things, well, practical.