We will assume that the full-wave and half-wave circuits use identical
diodes, identical load resistance and the voltages across half the
secondary winding of transformer used in full-wave circuit is the same
as the voltage across the secondary winding of the transformer used in
half-wave circuit.
(1)
In a half rectifier, one diode is used and the load current flows
during the positive half cycles of the input voltage. In a full-wave
rectifier, two diodes are employed and the load current flows during the
whole cycle of the input voltage.
(2) Unlike a half-wave rectifier, a full-wave rectifier circuit requires a centre-tapped transformer.
(3)
The peak-inverse voltage (PIV) in a half-wave rectifier is the maximum
voltage across the transformer secondary. In a full-wave circuit, the
PIV for each diode is two times the maximum voltage between the centre
tap and either end of the transformer secondary.
(4)
The frequency of the load current is the same as as the frequency of
the input supply for a half-wave circuit, and twice the frequency of the
input supply for a full-wave circuit.
(5)
The d.c. load current and the conversion efficiency for a full
rectifier are twice those of a half-wave rectifier. The ripple factor of
a full-wave circuit is also less, so that its performance is better
than that of the half-wave circuit.
(6)
In a full-wave circuit, the two diode currents flow through the two
halves of the centre-tapped transformer secondary in opposite
directions, so that there is no net direct-current magnetization of the
core. The transformer losses being smaller, a smaller transformer can be
used for a full-wave rectifier. This is an important advantage over a
half-wave rectifier.
