Lamp flasher using LM317

Description.
Here is a very useful lamp flasher circuit using the famous adjustable voltage regulator IC LM317T. LM317 can source up to 1A of current and so up to 12W lamps can be used with this flasher. Such a circuit finds huge application in automobiles. The frequency of the flashing depends on the value of resistors R1 to R3 and capacitors C2 to C4.With the given values; the flashing rate is around 5 flashes per second.

Circuit diagram.

lm317-lamp-flasher

Notes.

  • The circuit can be assembled on a Vero board.
  • Use 12V DC for powering the circuit.
  • Use a proper heat sink with the IC1.
  • Switch S1 can be a ON/OFF switch.
Show Comments

7 thoughts on “Lamp flasher using LM317

  1. RIYAZ

    Sir,
    I assembled this circuit but its not working properly as you mentioned.

    Please send me a circuit of a double flashing led circuits works in 12v dc.

    Reply
  2. deepak

    Hi
    I want to build a similar circuit with flashing rate of 1 flash in 5 & 10 seconds, please let me know the values of resisters and capacitors.
    Thanks in advance.

    Reply
  3. seetharaman

    Hi Elgardo this circuit can be used only up to 36 volts as the the operating voltage of this IC is limited to 39volts.

    Reply
  4. EDGARDO DIOLOLA

    HI, how can I have a circuit for this to be connected to a 48VDC battery supply as in the battery operated forklifts.
    I want only to know if it is possible to connect this circuit to a 48 volts battery supply , leaving the components from ADJ and OUT of the Regulator I.C. the same.
    Please provide the necessary circuit because I also want to assemble one for this circuit.
    Thanks in advance.

    Reply
  5. Kevin Lee

    Just “knocked” this circuit up, very easy, even after a 12 hour shift!
    Used it to make a high intencity LED flasher (stopped flashing) work again on the front of my recovery truck.
    It’s reduced the intencity very slightly, but other wise, perfect.
    Thank you John.
    Kev.

    Reply

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