The circuit diagram of a very simple voltage doubler using NE555 timer is shown here. Here IC NE555 is wired as an astable mutivibrator operating at around 9KHz. The base of the two transistors (Q1 and Q2) is shorted and output of the astable multivibrator (pin 3) is connected to it. When the output of astable multivibrator is low, Q1 will be OFF and Q2 will be ON. The negative terminal of the capacitor C3 will be shorted to ground through T2 and it will be charged to the input supply voltage. When the output of the astable multi vibrator is high, transistor Q1 will be ON and transistor Q2 will be OFF. The capacitor C4 will be charged to the voltage across capacitor C3 plus the input supply voltage (that is double the input voltage). This is how the circuit works.

This voltage doubler circuit can deliver only up to 50mA output current and above that current limit the output voltage will be dramatically reduced. The actual output voltage will be around 19V for a 12V DC input and also the output voltage will be a bit unstable. Anyway, for low current applications this circuit is well enough.

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Circuit diagram.

voltage doubler using NE555 timer

  • Notes.
  • The circuit can be assembled on a vero board.
  • The output current should not be allowed to exceed 70mA.
  • IC1 must be mounted on a holder.



    • Seetharaman

      Value of C2 is 0.05uF ceramic disc. This is a proven circuit check for the mistakes in the wiring.

  2. this ckt not working properly… voltage at ouput is same as provided at input…please tell me why is it not give desired output?

  3. can i know the value of the resistor connected to the 5th pin of the ic
    i 555 dc voltage doubler circuit

    • Seetharaman

      Hi pranitha it should be 0.05uF ceramic disc capacitor.

  4. what is the perpose of d2 and c4 ? Can i increase c3 to 220micro f ?

  5. Hi Admin and Seetharaman,
    Can you possibly direct me how to redesign this circuit to deliver a 2 ampere output?
    Is there any changes on the transistors Q1 and Q2?
    By the way, what is really the value of C2? IS IT 10nF OR 0.05uF,, are they the of same value?

  6. hi!!!!
    i want to take the 24volt output from the atx computer smps from 12v(red) wire is it possible to take..can any body help and suggests me for that

  7. sneha gosavi

    using 9v battery i am getting output as 7.9v what should i do?

  8. sneha gosavi

    hey if i m using same ckt for 9V then it wil work or not?

  9. how to get the dc voltage doubler ckt. using only dc components?

  10. send me voltage level detector circuit & description on my mail…….plz….

  11. seetharaman

    Hi Adnan 1N5819 or any rectifier diode used in SMPS or in Fly back power supply. You can even try 1N4148 or 1N4448. For 100mA use 1N4448

  12. is there any value of schotkey diodes like 1n4007???

  13. seetharaman

    Hi Adnan check whether your astable is working. if ok replace 1N4007 with scotkey diodes

  14. i connect the same equivalent but output is not doubled its remain same whats the problem??

  15. seetharaman

    Hi Adnan You are correct BC107(300mW) is BC547(220mW) BC177 is BC557. It is plastic variety with slightly less power dissipation. they are suited for this application

  16. excuse me the both transistors bc107 and bc177 is not available in my market i used bc547 and bc557 is the both replacement are correct or not???????

  17. seetharaman

    Hi Adnan When Q2 is on C3 -ve is connected input -ve supply and positive is connected through D1 to +12 volt supply. Hence the capacitor gets charged to 12volt. in the next cycle when Q1 is on and Q2 is off, in comming +12 volt is connected to -ve of the capacitor, which is already charged to 12 volt. since the in comming and capacitor are in series the voltage gets added after D2 you will get twice the input voltage. The capacitor C4 gets charged to 24 volt. For multiplying further refer to net for voltage multiplier circuits for generating very high voltage.
    Lowering cannot be done in this circuit

  18. please tell me the working of the circuit how the voltage will doubled and how we can get lower and more higher output?

  19. need 5ampere output,send a circuit diagram on my email

    • If you get that ckt diagram please send it on my mail

  20. can u design a circuit for a 230 volts main and to get a 460v output via transformer so that 460v can be tapped as two 230v outputs

  21. you are doing a great jobs… this organization is fruitful who all are hunting for to know technical facts…. congraz…