Minecraft wiki entry for Redstone_circuits, associated text: 1 Describing Circuits
1.1 Size
1.2 Features
2 Circuit types
2.1 Transmission circuit
2.2 Logic circuit
2.3 Pulse circuit
2.4 Clock circuit
2.5 Memory circuit
2.6 Piston Circuits
2.7 Miscellaneous circuits
3 Video
4 References