3.7 Volt Battery Charger & Indicator Circuit

Friends this is very simple circuit to indicate battery is full or empty. When Green led on it shows Battery is full and Red LED shows battery is empty. 

This is very simple circuit based on Transistor BC547. We are giving 5 volt as a input but this is more than require volt so don’t use high ampere charger with this circuit.

Also Read This:- Auto Cut-off 3.7 Volt Battery Charger

Parts List:-

  • Transistor BC547
  • Resistor 1k , 220ohm, 10k Variable Resistor
  • Diode IN4007, LED Green & Red

Circuit Diagram:-

3.7 v battery charger, 3.7 v battery indicator