LM3909 led flasher



LM3909 is a monolithic oscillator designed by National Semiconductor , to flash (LED) Light Emitting Diodes. Packaged in DIP 8 package LM3909 will operate  between -25 and 75 degree . LM3909  require to work only few components and can be used in many light electrical applications. LM3909 can be used in applications like : warning indicators powered by 1.4V to 200V, toys and novelties . This chip seems not in production right now, do you know any replacement IC? leave comment.

The main features of LM3909 are :

  • operation over one year from one C size flashlight cell
  • bright, high current LED pulse
  • few  external components- low cost
  • low voltage operation ( 1V to 5V )
  • low current drain (under 0.5 mA )
  • wide  temperature range

LM3909 Led flasher – [Link] + [PDF]


2 Response on “LM3909 led flasher

  1. The old LM3909 has not been made for so many years that National Semi doesn’t talk about it anymore.
    I bought one about 40 years ago.

    Why does Electronics-Lab talk about it??

  2. Is it not just a case that Flashing LED’s can be purchased now for the same price or less than non-flashing devices. If you can get the same function from a single component, why bother with the LM3909.

    I have a few of them somewhere in my parts collection, Never got round to making anything with them…

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