A feedback loop power controller is a device used to monitor and regulate the output of an electrical circuit. It consists of an input circuit, a comparison circuit, and an output control circuit. The input circuit measures the actual electrical output of the circuit. The comparison circuit then compares this input to a set target value. If the output does not match the target, the output control circuit is activated to adjust the output until it does match the target value. This adjustment is repeated until the desired output is achieved. With feedback loop power controllers, a system can maintain a constant output without frequent manual adjustments.