by Ari Dor
1. Redstone Dust
Redstone Dust is the wire of Minecraft: it takes a signal from an input to an output. When redstone dust is placed next to an input or output, it will turn into a line, one end always facing the input or output.1 If more redstone dust is placed beside the initial dust, it will bend towards the input/output and the new redstone.2 If redstone dust is placed with no input, output, or other dust on the blocks adjacent to it, it will be in dot form.3
If an input activates and a line of redstone dust 100 blocks long is attached to it, an output at the end will not activate. A redstone signal can’t travel more than 15 blocks, and so a repeater must be used to extend the signal to 31 blocks (+1 because of the repeater’s length of 1 block).4 When a signal reaches a repeater, it takes one tenth of a second for it to pass on the signal, meaning that a bunch of repeaters in a line to send a signal very far away would take awhile. By right-clicking the repeater, you can extend the time to pass on the signal to 2, 3, or 4 tenths of a second. By doing this, you will also make the signal last as long as your delay (for example: a 4 tenths of a second delay would make the pulse for the output last 4 tenths of a second).
3. Redstone Torch
A redstone torch is a constant power source that can be placed on all sides of a block except for the bottom. It will constantly face upwards, no matter how it is placed. Its function is simple: provide a constant redstone output until the block it’s placed5 on is powered, in which it will turn off. 6
4. Redstone Block
The redstone block is, well, a block of redstone. It’s like the redstone torch in that it produces a constant redstone output,7 but it can be moved around8,9 (not pulled downward due to a feature called Quasi-connectivity).