Combine transistor switches into AND, OR, NOT, and XOR, toggle the inputs, and watch signals flow along the wires while a live truth table lights up.
The transistor from the previous chapter was a switch that turned current on and off with voltage. So what if you wire two of those switches in series? Current reaches the end only when both are on, and stops the moment either one breaks — this is the AND gate. Toggle inputs A and B between 0 and 1 and watch how the output is decided. The wiring of the switches becomes the logic itself.
On the AND gate, toggle A and B and confirm the output is 1 only when both are 1.
