Single Phase Half Wave Controlled Rectifier

Single Phase Half Wave Controlled Rectifier, as the name suggests, is a rectifier circuit which converts AC input into DC output only for positive half cycle of the AC input supply. The word “controlled” means that, we can change the starting point of load current...

Phase Control of SCR – Definition, Explanation and Advantage

Definition: Phase Control of SCR means having control on the phase relationship between the start of current through the SCR and source voltage. Phase Control of SCR Explanation: Whenever we talk of phase angle, we generally mean the angle of a sinusoidal quantity at any...

Firing Angle of SCR Explained

Firing Angle of SCR is defined as the angle between the instant SCR would conduct if it were a diode and the instant it is triggered. We know that, there are two conditions which must be satisfied for turn on of an SCR. They are:...

Natural or Line Commutation- Principle with Circuit Diagram

Natural or Line commutation is a Class-F SCR commutation technique in which, a thyristor is turned off due to natural current zero and voltage reversal after every half cycle. This commutation method is only applicable for AC circuit and mostly used in Phase-Controlled Converters, Line-Commutated...

Class-E Commutation or External Pulse Commutation

Class-E Commutation is one of the forced commutation method to turn off an SCR / Thyristor. An external current pulse is used in this technique to commutate SCR. This is the reason, Class-E commutation is also known as External Pulse Commutation. This external current pulse...

Class-D Commutation – Impulse Commutation of Thyristor

Class-D Commutation is a commutation method used to turn off thyristor in a DC circuit by the application of a sudden reverse voltage across the terminals of SCR. This is the reason, it is also called Impulse Commutation. A Class-D commutation circuit consists of Main...

Class-B or Resonant Pulse Commutation of SCR

Class-B or Resonant Pulse Commutation is a forced commutation technique to turn off an SCR. In this technique, thyristor or SCR is turned off by gradual build-up of resonant current in the reverse direction i.e. from cathode to anode of SCR. This technique is also...

Load Commutation of SCR – Class A Commutation

Load commutation of SCR is a forced commutation technique in which SCR is forced to turn off. Turning off an SCR essentially requires its anode current to fall below holding current and a reversed biased voltage must be present across SCR for sufficient time so...