8.2 Full wave rectifier

  Semi-conductor Devices and Electronics

A full wave rectifier is a circuit arrangement which makes use of both half cycles of an input alternating current (AC) and convert them to direct current (DC).
Full wave rectifier is much more efficient than a half wave rectifier.
This process of converting both half cycles of the input alternating current (AC) to direct current (DC) is termed full wave rectification.

Full wave rectifier is of two types,

1. Center tapped full wave rectifier
2. Bridge full wave rectifier

1. Centre tapped full wave rectifier

In the case of centre-tap full wave rectifier, only two diodes are used, And are connected to the opposite ends of a centre-tapped secondary transformer as shown in the figure below.

Bridge full wave rectifier is an arrangement of four (or more) diodes in a bridge circuit configuration that provides the same polarity of output for either polarity of input. The construction of bridge full wave rectifier is as shown below.

• Peak value of current is, $${I_m} = \frac{{{V_m}}}{{{r_f} + {R_L}}}$$

where,
$r_f$: Forward diode resistance
$R_L$: Load resistance$V_m$: Peak value of the alternating voltage

• $rms$ value of current is, $${I_{rms}} = \frac{{{I_m}}}{{\sqrt 2 }}$$
• DC value of current is, $${I_{DC}} = \frac{{2{I_m}}}{\pi }$$
• Peak inverse voltage is, $$PIV = 2{V_m}$$
• DC value of voltage is, $$\begin{equation} \begin{aligned} {V_{DC}} = {I_{DC}}{R_L} \\ {V_{DC}} = \frac{{2{I_m}}}{\pi }{R_L} \\\end{aligned} \end{equation} $$