Electronics simulators
The components a circuit is built from, opened up: charge, fields and carriers doing the work.
Resistor
The field pulls an electron along and the lattice knocks it back to random, over and over. The average of that stop-start crawl is the current, and the winnings the lattice keeps are the heat.
Diodes & Transistors
Pick a diode or a transistor and watch electrons and holes move through it: a one-way valve, then a valve with a knob, both built from a barrier you can raise.
Capacitor
Every charge is a ball you can count. Drive the source by hand and watch electrons get dragged off one plate, round the circuit, and onto the other one.
Inductor
A flywheel for charge. Shove the source and the electrons will not jump, only ramp, and cutting them off makes the collapsing field fight to keep them going.
Memristor
A resistor that remembers the charge that has been through it. Watch the boundary inside the film move as you drive it, and stay put when you stop.
RC, RL and RLC Circuits
A resistor, a coil and a capacitor in one loop. The two stores pass energy back and forth, so the circuit rings, and one number, the damping ratio ζ, decides whether it rings, settles as fast as it can or crawls. The same two poles decide which frequencies get through.
Transmission Lines
Close a switch on a two-wire line and watch the energy travel through the space between the wires, not down the copper, as a wave at v = 1/√(LC) that the load swallows, doubles or turns upside down.
MOSFET & CMOS Logic
A plate of metal that conjures a wire underneath itself and never touches it. Then stack a p-type one on an n-type one and get a gate that costs power only while it changes its mind.