Minecraft wiki entry for Miscellaneous, associated text: A thyristor is a bit like a D flip-flop but has a different functionality. It has two inputs: the "gate" line G and the "anode" line A, and has one output: the "cathode" line K. When triggered by G, the circuit sets its output K to A if A is high, then holds that output state until A goes low. Otherwise K stays low.