1.5V LED Flasher Oscillator


Posted on Feb 5, 2014

The 8-lead plastic mini-DIP LM3909 IC was developed by National Semiconductor in the mid `seventies of the past century. It was a monolithic oscillator specifically designed to flash Light Emitting Diodes. By using the timing capacitor for voltage boost, it delivered pulses of 2 or more volts to the LED while operating on a supply of 1. 5V or less.


1.5V LED Flasher Oscillator
Click here to download the full size of the above Circuit.

The circuit was inherently self-starting, and required addition of only a battery and capacitor to function as an LED flasher. Unfortunately, since 1998, the manufacturer discontinued the production of this chip. For this reason, and on request of some correspondents, I tried to emulate this IC operation using common discrete components, obtaining unexpected satisfactory results.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    VGA to TV converter II
    LCD Car Accelerometer
    Octave Equalizer Circuit
    Audio 5 Band equalizer using IC BA3812L
    digital counter circuits
    Versatile Op Amps Need No Resistors
    Model Railway Short-Circuit Beeper
    Induction Cooker
    The beginning and end of a three-phase motor winding speed judgment circuit



    Top