User:LB1/Redstone Power Types

There are four kinds of redstone power based on the interaction between block faces and other blocks; Input, Intermediate, Dust, and Output. The same block can emit different power types from different faces, but solid blocks always emit the same kind of power from their output faces.

Note: assume that "lever" includes both Levers and Tripwire Hooks, and that "pressure plate" and "button" include both the wooden and stone varieties.

Input Power
Input power is the strongest type of redstone power. Input power comes from the side of a lever/button/pressure plate mounted to a block, the top of a redstone torch, and the side of the repeater that its texture points to. Input power can both directly power redstone dust and redstone devices, or it can power solid blocks which will emit Intermediate power from all other faces.

Intermediate Power
Intermediate power is, as the name suggests, intermediate, and is the most common kind of redstone power. Solid blocks receiving Input power, the sides of redstone torches, the bottoms of wall-mounted redstone torches, and the sides of levers/buttons/pressure plates not mounted to a block all emit Intermediate power. Devices and redstone dust can receive redstone power from intermediate power sources.

Dust Power
As you would guess, Dust power is the kind of power that redstone dust emits. Redstone dust emits Dust power to the block directly below the dust and the blocks the edges of the redstone dust are touching. Dust power that is transmitted to solid blocks will cause the solid blocks to emit Output power. Dust power can power devices. This explains why the sides and tops of redstone dust do not power devices; those faces do not emit Dust power.

Output Power
Output power is the weakest kind of power, as it cannot even power redstone dust. Output power comes from solid blocks that receive Dust power. Output power is only strong enough to power redstone devices and to affect attached redstone torches.

Interaction with Redstone Torches
Because redstone torches can only be mounted directly on solid blocks (we're ignoring glass here because glass cannot transmit any kind of redstone power), redstone torches cannot possibly receive/be affected by Input power or Dust power; they can only be affected by Intermediate and Output power.

Solid Block Interaction
Block solidity places an important role in redstone power. Some blocks are directionally solid, like fences, which are only solid on the top and bottom faces, with the other faces acting transparent. Only solid faces of blocks can receive or emit redstone power. Here's a quick jump table; Power In is the power type touching one solid face of the block, Power Out is the power type emitted from the other solid faces of the block.

Redstone "Devices"
A redstone device is a block that reacts to all four kinds of redstone power, but not solely because of block updates. This includes:
 * Redstone Repeaters
 * Pistons
 * Dispensers (ignoring the bugs)
 * Redstone Lamps
 * Powered Rails
 * TNT (ignoring the bugs)
 * Doors and Trapdoors
 * Fence gates