Microchips

On the outside a microchip (also called integrated circuit, IC, or chip) looks like a flat black rectangle about the size of a dime and with a bunch of wires (called pins) sticking out of it. These pins attach to the wires of the bus (i.e., the motherboard).

Inside, the chip is a dense network of transistors. A transistor is a microscopically small switch that can be turned on and off electronically:

Transistors can be turned on and off quickly because they have no moving parts. Instead, transistors are made out of a type of material that conducts electricity when it receives power (in other words the switch is "closed") but does not conduct electricity when there is no power (the switch is "open"). We call such devices semi-conductors.