An SCR (Silicon Controlled Rectifier) power regulator – also called a thyristor power controller – is a solid-state device that precisely controls the amount of AC power delivered to a load, usually an industrial heating element or transformer. It uses back-to-back SCRs or a TRIAC to rapidly switch the AC waveform. By varying the point in each half-cycle (phase-angle control) or the number of full cycles conducted (zero-cross/burst control), it adjusts the effective voltage, current, or power supplied to the load.