Explain with circuit diagram the operation of class C commutation.

Ans:

Circuit Diagram:

Working:-

• At first, when the SCR1 is triggered load current flows IL starts flowing through (Vdc+, RL, SCR1, Vdc-). 

• At the same time, capacitor ‘C’ will charge through Vdc+, R, C, SCR1, Vdc- with right side plate positive.  

•  When it is fully charged to Vs charging current becomes zero.  

•  To turn off SCR1, SCR2 is triggered.  

•  When SCR2 is turned ON the reverse voltage across ‘C’ is applied across SCR1, turning it OFF.  

•  Now capacitor will start charging through Vdc+, RL, C, SCR2, Vdc- with left side plate positive.  

•  Similarly, as SCR1 is turned ON the reverse voltage across ‘C’ is applied across SCR2, turning SCR2 OFF. 

Note: Waveform is optional.