Filter in Full Wave Rectification

Filter Capacitor in Full Wave Rectification

Half Wave Rectification converts one-half of the input ac signal into pulsating dc signal. This article covers this in detail. 

Full Wave Rectification converts both halves of the ac signal into pulsating dc signal.

Full Wave Rectification with two Diodes is covered here.

And full Wave Rectification with four Diodes is covered here.

The output is fluctuating, to smoothen the output, a filter capacitor is used.

What a filter is and how it smoothens the output is covered in detail here.

Here we discuss briefly full Wave Rectification with a filter Circuit. 

To smoothen the output of a full Wave rectifier, a capacitor is used. 

The rectified output from the full-wave rectifier is a pulsating DC signal with ripple. 

The capacitor is connected in parallel to the load resistor in the circuit.

During the positive half-cycle, the capacitor charges to the peak voltage of the positive half-cycle. During the negative half-cycle, the capacitor discharges slowly.

Consequently, the capacitor acts as a storage device, charging and discharging during the gaps between the AC half-cycles.

This forms a smoother DC signal by reducing the ripple voltage. 

Input Signal

Output Signal

Output Signal with Capacitor

Output Signal with Capacitor

Output Signal with Diode reversed

Output Signal with Diode reversed and filter capacitor

                                       

Output Signal with Diode reversed and filter capacitor

Smoothness of Output 

The time constant of the RC circuit (resistor and capacitor) determines the smoothness of the output. 

The larger the capacitor value or the smaller the resistance value, the slower the capacitor discharges, leading to a smoother output with less ripple voltage.

The images show this relation practically.