A rectifier circuit takes an alternating current and passes it through a diode circuit which allows the current to flow through one pair of diodes for half a cycle and the other pair of diodes for the other half of each cycle. Direct current emerges and the current and voltage is said to have been rectified.
When the input current flows in the positive direction, current flows in at A, through the diode in arm AB, and out at B. Current flows from the output in at D, through the diode in arm DC and out at the input at C.
When the input current flows in the negative direction, current flows from the diode circuit into the input at A, having come through the diode in arm DA, and before this, the output terminal at D. Current flows from the input at C through the diode in arm CB at out at B.
