Projects

Half Wave Rectifier

  Aim

  To design and simulate a Half Wave Rectifier circuit.

  Components

Name

EDWin Components Used

Description

Number of components required

RES RC05 Resistor 1
DIODE 1N4007 Diode 1
VGEN SMB_VGEN Ac voltage source 1
GND SMB_SPL0 Ground 1

 

  Theory

  The Half wave rectifier is a circuit, which converts an ac voltage to dc voltage.

  In the Half wave rectifier circuit shown above the transformer serves two purposes.

  1. It can be used to obtain the desired level of dc voltage (using step up or step down transformers).
  2. It provides isolation from the power line.

  The primary of the transformer is connected to ac supply. This induces an ac voltage across the secondary of the transformer.

  During the positive half cycle of the input voltage the polarity of the voltage across the secondary forward biases the diode. As a result a

  current IL flows through the load resistor, RL. The forward biased diode offers a very low resistance and hence the voltage

  drop across it is very small. Thus the voltage appearing across the load is practically the same as the input voltage at every instant.

  During the negative half cycle of the input voltage the polarity of the secondary voltage gets reversed. As a result, the diode is reverse biased.

  Practically no current flows through the circuit and almost no voltage is developed across the resistor. All input voltage appears across the diode

  itself.

  Hence we conclude that when the input voltage is going through its positive half cycle, output voltage is almost the same as the input voltage

  and during the negative half cycle no voltage is available across the load. This explains the unidirectional pulsating dc waveform obtained

  as output. The process of removing one half the input signal to establish a dc level is aptly called half wave rectification.

 Peak Inverse Voltage

  When the input voltage reaches its maximum value Vm during the negative half cycle the voltage across the diode is also maximum. T

  his maximum voltage is known as the peak inverse voltage. Thus for a half wave rectifier

  Let Vi be the voltage to the primary of the transformer. Vi is given by

  where Vr is the cut-in voltage of the diode.

 Ripple Factor

  Ripple factor is defined as the ratio of rms value of ac component to the dc component in the output.

Ripple factor

  Vav the average or the dc content of the voltage across the load is given by

  RMS voltage at the load resistance can be calculated as

  Ripple Factor

 Efficiency

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

Thus

 Transformer Utilization Factor

  Transformer Utilization Factor, TUF can be used to determine the rating of a transformer secondary.

  In half wave rectifier the rated voltage of the transformer secondary is

  But actually the RMS current flowing through the winding is only .

 Form Factor

  Form factor is given by,

 Peak Factor

  Peak factor is given by,

  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.