Half Wave Rectifier [Explained] in Detail

Half Wave Rectifier

Half wave rectifier is a simple circuit which is basically used for converting an AC voltage to the DC voltage. It is a simple diode or a group of diodes which converts AC (Alternating Current) voltage into DC (Direct Current). It is used in end number of electronic devices.

Principle of Half Wave Rectifier

The half wave rectifier circuit is a diode. And, a diode works and allows current in only one direction and blocks it in another one. So, the basic principle on which rectifier works and are constructed is the working of a diode only.

If a circuit, contains group of diodes then the proper arrangement of all the diodes is must. The simplest known form of the rectifier is the half wave rectifier.

half wave rectifier waveform

half wave rectifier waveform

Half Wave Rectifier circuit diagram

Half Wave Rectifier circuit diagram

Components of Half Wave Rectifier

  • Stepdown transformer is used for reducing or increasing the AC voltage. Step-up transformer is used for increasing the voltage from low to high, whereas a step-down transformer is used for reducing the AC voltage from high to low that is vice-e-versa of the step-up transformer, The step-down transformers are the main components in potential transformer which has the very different function than that of rectifier.

In the rectifiers, mostly step-down transformers are used as the AC voltage source required by the diode is very less.

And, a step-down transformer has more number of turns in the primary winding than the secondary winding; that is why the AC voltage is reduced when it moves from the primary to the secondary winding.

  • An AC source simply provides the AC (Alternating Current) voltage to the half wave rectifier circuit.
  • Resistor or a load is an electrical component which is used for restricting the flow of current to a certain level.
  • Diode  is a basic and an important component in the rectifier. The electronic device that blocks the movement of current in another direction, when it is moving in one direction.
  • Electrolytic capacitors usually act as a filter in the half wave rectifier circuits. They are used in the circuit for reducing the ripple voltage. While attaching the capacitor to the half wave rectifier circuit, you should properly connect it as such that the polarity matches, because then only current can pass through it. This should be kept in mind because if the electrolytic capacitor is attached in the reverse polarity, then it may get damaged.

Diode should always be placed between transformer and resistor.

Half wave rectifier can be of two types:

  1. Positive half wave rectifier
  2. Negative half wave rectifier

Working of the Half Wave Rectifier

The working of the half wave rectifier is completed in two cycles that are half wave positive and negative cycles.

  • The diode is under the forward bias condition during the positive half cycle. And, the current is conducted to the load resistance.
  • So, the voltage is established across the diode.
  • And, the diode is under the reverse bias condition during the negative half cycle. And, so there is no movement in the circuit and current flow equals to zero.
  • So, only the voltage which was established in the diode is there; which is the net result of the positive half cycle of the circuit.
  • And, the generated output voltage is responsible for pulsing the Dc voltage from the half wave rectifier circuit.

Also see 3 phase transformer



This article has 7 comments

  1. Raul Cheroki Reply

    Nicely explained.
    However, i have a doubt why does we use the capacitor at the output of the rectifier ?
    I mean, we always get the ripple at the last ! Isn’t it ?

  2. Caron Brookover Reply

    Can the Half wave rectifier be used to get the output similar to the chopper with minimum or no ripple in the output voltage ?


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