Describe with circuit diagram the operation of battery charger using SCR.

Ans:

Circuit Diagram:

 

Working: 

•  The figure above shows battery charger circuit using SCR. 
•  A 12V discharged battery is connected in series with an SCR T1.The single-phase 230V supply is stepped down to (15-0-15) V by a centre-tapped transformer. 
•  The diodes D1 and D2 provide full wave rectified output across the SCR, T1 and the battery to be charged. 
•  R3 –D3 provide trigerring circuit for T1. AS T1 is ON battery starts charging. 
•  When the battery is full, voltage provided by the voltage divider circuit will become the zener voltage making the SCR T2 to switch ON. 
•  When T2 is ON a short circuit results in the voltage divider circuit R3 & R4, making T1 to switch OFF. 
•  This prevents over charging of the battery.