Bridge Rectifier

Aim

To simulate a Bridge Rectifier circuit.

Components

Theory

The Bridge rectifier is a circuit, which converts an ac voltage to dc voltage using both half cycles of the input ac voltage. The Bridge rectifier circuit

 is shown in the figure. The circuit has four diodes connected to form a bridge. The ac input voltage is applied to the diagonally opposite ends of

the bridge. The load resistance is connected between the other two ends of the bridge.

For the positive half cycle of the input ac voltage, diodes D1 and D3 conduct, whereas diodes D2 and D4 remain in the OFF state.

The conducting diodes will be in series with the load resistance R_L and hence the load current flows through R_L.

For the negative half cycle of the input ac voltage, diodes D2 and D4 conduct whereas, D1 and D3 remain OFF. The conducting diodes D2 a

nd D4 will be in series

with the load resistance R_L and hence the current flows through R_L in the same direction as in the previous half cycle. Thus a bi-directional

wave is converted into a unidirectional wave.

Peak Inverse Voltage

Peak inverse voltage represents the maximum voltage that the non- conducting diode must withstand. At the instance the secondary

voltage reaches its positive peak value, Vm the diodes D1 and D3 are conducting, where as D2 and D4 are reverse biased and are

non-conducting. The conducting diodes D1 and D3 have almost zero resistance. Thus the entire voltage V_m appears across the load resistor

R_L. The reverse voltage across the non-conducting diodes D2 (D4) is also V_m. Thus for a Bridge rectifier the peak inverse voltage is given

by

 

Ripple Factor

The ripple factor for a Full Wave Rectifier is given by

The average voltage or the dc voltage available across the load resistance is

 

RMS value of the voltage at the load resistance is

Efficiency

Efficiency, h is the ratio of the dc output power to ac input power

The maximum efficiency of a Full Wave Rectifier is 81.2%.

Procedure

EDWin 2000 -> Schematic Editor: The circuit diagram is drawn by loading components from the library. Wiring and proper net assignment has been made. The values are assigned for relevant components.

EDWin 2000 -> Mixed Mode Simulator: The circuit is preprocessed. The test points and waveform markers are placed in input and output of the

 circuit. GND net is set as reference net. The Transient Analysis parameters have been set. The Transient Analysis is executed and output

waveform is observed in Waveform Viewer.

Result

The output waveform may be observed in the waveform viewer.