Parallel fully automatic pulse charger circuit diagram

NE555 constitutes a multivibrator, and its output terminal controls the on and off of the thyristor; IC2 is a voltage comparator. When the battery is not connected, the "+" terminal of the comparator is higher than the level of the "-" terminal through the pull-up resistor, so the comparator outputs a high level and the LED does not light up. When a battery with insufficient voltage is connected, the level of the "+" terminal of the comparator is lower than the "-" terminal, and the output is low level. The transistor is turned on when pin 3 of IC1 is high level to charge the battery. When pin 3 of IC1 is at low level, it is cut off. The battery discharges through the collector with a small current, and the light-emitting tube also emits light periodically (because the discharge current is small, it is not enough to make the light-emitting tube light during discharge). When the battery is fully charged , the potential of the "+" terminal of the comparator is higher than that of the "-" terminal, the output is high level, the triode is cut off, and the luminous tube does not light up for a long time, indicating that charging is completed.