⚠ This is for beginners and very much by a beginner / hobbyist
It's intended to get an intuitive overview for hobbyist needs. It may get you started, but to be able to do anything remotely clever, follow a proper course or read a good book.
Some basics and reference:
Volts, amps, energy, power · batteries · resistors · transistors · fuses · diodes ·
capacitors · inductors and transformers ·
ground
Slightly less basic: amplifier notes · varistors ·
changing voltage · baluns ·
frequency generation ·
Transmission lines · skin effect
And some more applied stuff:
IO:
Input and output pins · wired local IO · wired local-ish IO · · Various wireless · 802.11 (WiFi) · cell phone
Sensors: General sensor notes, voltage and current sensing ·
Knobs and dials ·
Pressure sensing ·
Temperature sensing ·
humidity sensing ·
Light sensing ·
Movement sensing ·
Capacitive sensing ·
Touch screen notes
Actuators: General actuator notes, circuit protection ·
Motors and servos ·
Solenoids
Noise stuff: Stray signals and noise · sound-related noise names · electronic non-coupled noise names · electronic coupled noise · ground loop · strategies to avoid coupled noise · Sampling, reproduction, and transmission distortions
Audio notes: See avnotes
Platform specific
- Arduino and AVR notes · (Ethernet)
- Microcontroller and computer platforms ··· ESP series notes · STM32 series notes
Less sorted: Ground ·
device voltage and impedance (+ audio-specific) · electricity and humans ·
power supply considerations ·
Common terms, useful basics, soldering ·
landline phones ·
pulse modulation ·
signal reflection ·
Project boxes ·
resource metering ·
SDR ·
PLL ·
vacuum tubes ·
Multimeter notes
Unsorted stuff
Some stuff I've messed with: Avrusb500v2 ·
GPS ·
Hilo GPRS ·
JY-MCU ·
DMX ·
Thermal printer ·
See also Category:Electronics.
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✎ This article/section is a stub — some half-sorted notes, not necessarily checked, not necessarily correct. Feel free to ignore, or tell me about it.
Say you have two imprecise bimetal blinkers, and you could forcibly make one trigger when the other one triggers, then even these messy components would never perceptibly drift.
PLL is a little more than that.
PLL says "okay, you've got an oscillator, and you've got a reference signal you want to synchronize to.
We'll build a feedback system that will tune our own oscillator to match the reference, in phase and frequency"
This involves
- a phase difference detector - outputs a voltage proportional to the difference between ourselves and the reference
- a loop filter, filtering that detectors's output to take out some noise, so that it is more stable when used as something that modulates/adjusts. Usually a lowpass.
- a way to feed this adjustment to our own oscillator
- which is not very hard when it is a VCO -- because that means 'voltage controlled'
Uses:
- FM demodulation, clock recovery, and as such is common in RF equipment,
- frequency synthesizers, which govern communication between chips (verify)
https://www.youtube.com/watch?v=A9qt0JYdvFU
https://www.allaboutcircuits.com/technical-articles/understanding-pll-applications-frequency-multiplication/
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