Electrical Power Supply

When an alternating current is converted to direct current, small voltage variations at the supply frequency are difficult to smooth out, or filter, completely. In the case of power supplies operated from the 60-Hz power line, the result is a low-frequency variation in the power supply's output called ripple voltage. Ripple voltage on the power supply output will add with the signals processed by electronic circuitry, particularly in circuits where the signal voltage is low. Ripple can be minimized by using more elaborate filter circuitry but it can be reduced more effectively with active voltage regulation. A voltage regulator can respond fast enough to cancel unwanted changes in the voltage.