Full Wave Rectifier

FULL WAVE RECTIFIER

Figure (3.70) shows centre tapped full wave rectifier. In full wave rectifier, the rectifying element conducts in both positive and negative cycles of the input signal.

Due to centre tapping, the impedance of the two halves of windings are equal. Hence, the voltages in two halves are 180° out of phase.

During positive half cycle of input, the D1 is conducts and D2 is in off state. The current flows through the load resistor RL While negative half cycle of input, D2 conducts and D1 is in off state. The current flows through the load resistor RL.

1. Average DC Load Current (IDC)

Consider one cycle of load current IL from 0 to 2л to obtain the average value which is dc value of load current.

2. Average (or) DC load voltage (VDC)

The dc voltage is,

3. RMS Load Current (IRMS)

The RMS value of current can be obtained as follows,

4. DC Power Output (PDC) 

DC power output written as,

5. AC Power input (PAC) 

AC power input written as,

6. Rectifier Efficiency (η)

This is the maximum theoretical efficiency of full wave rectifier. (i.e.) efficiency of full wave rectifier is twice times of half wave rectifier efficiency.

7. Ripple Factor

As derived earlier in case of half wave rectifier the ripple factor is given by a general expression,

8. Transformer Utilization Factor (TUF)

In full wave rectifier, the secondary current flows through each half separately in every half cycle, while the primary of transformer carries current continuously.

Hence TUF is calculated for primary and secondary windings separately and then the average TUF is determined.

For secondary,

We know that a full wave rectifier consists of two half wave rectifiers.

Therefore, TUF for primary = 2 × TUF of HWR

(TUF)P = 2 × 0.287 = 0.574

9. Voltage Regulation

For full wave circuit,

10. Peak inverse Voltage of Full Wave Rectifier.

Peak inverse voltage of full wave rectifier is twice the value of Half wave rectifier,

Circuit diagram for peak inverse voltage:

Disadvantage of Full wave Rectifier

Design and maintenance of center tapped transformer is difficult.