The Repeater functions the same as its vanilla counterpart, except it has a total of 9 delay settings, ranging from almost instantaneous to more than 12 seconds. The different delay settings are 1, 2, 3, 4, 8, 16, 32, 64, or 128 ticks. For comparison, the vanilla repeaters' settings are 1, 2, 3, or 4 ticks.
The Repeater also acts as a diode, meaning that it can keep a redstone current travelling in one direction only.
Normally, redstone current lasts 15 blocks. After that, you must have a repeater. The repeater expands the current by 15 more blocks. This allows for infinitely long redstone circuits, assuming Repeaters are placed as needed. They are also used to create circuits where a delay is desired, such as for priming TNT.
As ticks relating to redstone are equal to one normal tick, the different settings are as follows:
|Setting (Right Click)||Number of Ticks||Seconds In-Game|