Introduction: Over & Under Voltage Protection for Battery or Power Supply

About: I am a electronics hobbyist from india. Youcan visit my youtube channel "AviPrink" for more detailed information.

Welcome Again To this Article today we learn about how we can set under voltage and over voltage for any power supply or protect any battery from under discharge and over charge.

Step 1: Schematic Diagram

Assemble all the required components according to circuit diagram.


  • Voltage From 3 to 32 volt (For 32 volt Relay Need to be changed or use of voltage regulator is recommended for voltage lower then 7 volt i recommend you to use lower value zener diode eg- 2 or 3 v zenor diode) is supplied to this circuit as input.
  • A 5 volt zener diode is used to set reference voltage for OP-Amp (if we use voltage divider instead of zener we could not get fixed reference voltage as supply voltage changes reference voltage also changed).
  • 2x 10kOhm Variable resistors are used to set Over & Under Voltage Limits.
  • U1 is responsible for over voltage protection and U2 is responsible for under voltage Protection.
  • Transistor used in this project is NPN Type.
  • Relay Used In this Project is SPDT.

Step 2: Finished

Do It

Or please Let Me notify if you have any problem.

You can also visit my channel for more info.Channel