Battery charger charging status display circuit

Shown is the charging status display circuit of the battery charger . The AC 220 V voltage is stepped down to 10 V by the transformer, and then rectified and filtered to form a DC voltage, which is added to the thyristor (silicon controlled thyristor SCR l) and the display control circuit respectively . After the power is turned on, the voltage at point a rises. This voltage triggers the thyristor to charge the battery. At the same time, the red light-emitting diode has current, and the diode lights up to indicate the start of charging. When the charge reaches the rated value , the voltage at both ends of the battery rises, causing the slider voltage of the potentiometer VR1 to rise, and the positive (+) terminal voltage of the operational amplifier to rise. The operational amplifier outputs a high level to turn on the thyristor SCR 2, which emits green light. The diode emits light, the voltage at point A drops, charging stops, and the red LED goes out.