This 1.3V power supply can be used as replacement for the 1.3V Mercury Cell in any circuit. When the input 5V is given to the circuit, the  voltage drop across  zener diode D1 will be around 2V.The diode D2 will drop a 0.7 V from the 2V volt and the remaining 1.3V will be available at the output. The Resistor R1 limits the current through Zener diode

Circuit diagram with Parts list.


  • The circuit can be assembled on a general purpose board.
  • This power supply is suitable for devices like digital multimeters, digital clocks, digital thermometers etc.
  • The zener diode D1 can be a 2V one like BZX552V0

1 Comment

  1. seetharaman

    thanks for the nice idea for a good regulated one. my simple circuit in use for a long time with me is, connect 2nos 1N4007 in series in place of D1 and use the out put across these 2 diodes, which will be 1.3volt.