Notes
Electronics explained from the beginning: what each part does, why the circuit is built that way, and the ones I keep running into.
Button Input: Debounce & Pull-Up/Down Resistors
A button is just a switch, so why does it need a resistor? What a floating pin does to a chip, why one press can be read as five, and how to fix both.
Isolation & GPIO Driver: MOSFET, BJT, Relay, Optocoupler
A chip pin can supply a few milliamps; a lamp strip or a motor wants amps. This is how a transistor, a relay or an optocoupler lets a small signal switch something big.
Power Supply: LDO, Buck & Boost Converters
Where to start when a project needs power: the three questions to ask first, why one regulator runs hot and another gets noisy, and why a battery needs a guard as well as a charger.
Signal Amplification: Op-Amp & Voltage Comparator
A sensor hands you a signal that is too small to measure. This is how an op-amp makes it bigger without wrecking it, and how a comparator turns it into a simple yes or no.
Signal Filtering: RC High-Pass & Low-Pass
One resistor and one capacitor can take out noise, smooth a PWM signal or block a DC offset. This is what that pair actually does, and when to reach for it.
Electronics Fundamentals: Self-Study Notes
Start here if electronics still feels like magic. What voltage and current actually are, why a lamp lights up the instant you flip the switch, and what each part on a circuit board is doing.