Full Wave bridge rectifier circuit with working explanation

What is a rectifier? A rectifier is an electronic circuit that converts AC voltage to DC voltage. It can be implemented using a capacitor diode combination. The unique property of diodes, permitting the current to flow in a single direction is utilized in here.

Now what is a bridge rectifier? Bridge rectifier is a full wave rectifier circuit using the combination of four diodes to form a bridge. It has the advantage that it converts both the half cycles of AC input into DC output.

Rectifiers are one of the basic electronic circuits. If you are an electronic hobbyist then this tutorial will help you to get started with your lessons in electronic circuits.

A good bridge rectifier power supply (rectifier applications) is essential to start your home electronics lab. Below is the full wave bridge rectifier schematic and operation explanation in detail.

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Full wave bridge rectifier circuit diagram

Components Required

Step down transformer-1 (230V to 12V or 110V to 12V)
Diodes-4 (1N4007)
Capacitor-1 (470µF)
Led-1 (Red)
Resistor-1 (1K)

NOTE: You can use step down center tapped transformer as well as ordinary step down transformer. If you choose a center tapped transformer it is possible to change the output DC. By connecting middle point and a terminal point of transformer to rectifier or by connecting both terminal points of transformer to the rectifier voltage can be changed.

Working of a bridge rectifier

During the positive half cycle of secondary voltage, diodes D2 and D3 are forward biased and diodes D1 and D4 are reverse biased. Now the current flows through D2-->Load-->D3

During the negative half cycle of the secondary voltage, diodes D1 and D4 are forward biased and rectifier diodes D2 and D3 are reverse biased. Now the current flows through D4-->Load-->D1

In both the cycles, load current flows in the same direction. Hence we get a pulsating DC voltage as shown in fig (2).

Fig (1). Input sine wave

Fig (2). Pulsating DC output

Addition of a capacitor at the output converts the pulsating DC voltage to fixed DC voltage.

Upto a time period of t=1s input voltage is increasing, so the capacitor charges up to peak value of the input. After t=1s input starts to decrease, then the voltage across the capacitor reverse biases the diodes D2 and D4 and therefore it will not conduct. Now capacitor discharges through the load, then voltage across the capacitor decreases.

When the peak voltage exceeds the capacitor voltage, diodes D2 or D4 forward biases and as a result capacitor again charges to the peak value. This process continues. Hence we get almost smooth DC voltage as shown in fig (3).