Integrated Circuits
An integrated circuit is the result of forming transistors, diodes and resistors onto a small chip of silicon connected with aluminum wires. Integrated circuits can contain a few to hundreds of thousands of transistors. Technology has exploded since their discovery as they allow digital watches, video games, far cheaper computers and much more.
Analog IC
These amplify, produce or respond to variable voltages. Analog IC's include many types of timers, amplifiers, oscillators and more.
Digital IC
Digital integrated circuits produce or respond to signals with two voltage levels (representing on and off - binary 1 / 0). Uses include computers, processors, memories, and smaller chips used in many modern digital applications. All digital integrated circuits are made from gates which are electronically controlled switches. Used gates include the 'AND', 'OR', 'NOT' (or inverter), 'NAND', and 'NOR'. The first two gates are actually NAND / NOR gates with a NOT gate as transistors naturally invert!