Full wave rectifier, Basic full wave rectifier

A Full Wave Rectifier is a circuit, which converts an ac voltage into a pulsating dc voltage using both half cycles of the applied ac voltage. It uses two diodes of which one conducts during one half cycle while the other conducts during the other half cycle of the applied ac voltage.

During the positive half cycle of the input voltage, diode D1 becomes forward biased and D2 becomes reverse biased. Hence D1 conducts and D2 remains OFF. The load current flows through D1 and the voltage drop across R_L will be equal to the input voltage

The half-wave rectifier chopped off half our signal. A full-wave rectifier does more clever trick: it flips the - half of the signal up into the + range. When used in a power supply, the full-wave rectifier allows us to convert almost all the incoming AC power to DC. The full-wave rectifier is also the heart of the circuitry that allows sensors to attach to the RCX in either polarity.