Equivalent IC

Discussion in 'General Electronics Chat' started by MIRINGU, Jun 12, 2008.

  1. MIRINGU

    Thread Starter Active Member

    Mar 18, 2007
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    0
    Please help me with an equivalent Ic to LM3909 LED flasher/oscillator
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,647
    2,346
    Hello,

    I could not find an equivalent IC.
    I found a little circuit to let more leds flash using 1 flashled.
    D7 is a flashled, the current it draws will trigger the transistor to let the other leds (D1-D6) flash too.
    The circiut comes from a dutch cirtcuit site.
    I think it would be safer to put a resistor in series with the leds D1-D6 to limit the current.
    The number of leds is dependent on the color you want to use (red and green are ca. 1.7-2 Volts, bleu and white are ca. 3.5-4 Volts).

    Greetings,
    Bertus
     
  3. RiJoRI

    Well-Known Member

    Aug 15, 2007
    536
    26
    Have you considered using a 555 timer, or an op-amp, or even an 8-pin micro?

    --Rich
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Take a look at Bill Bowden's 1.5v dual LED flasher. It's not exactly like the LM3909, but it does something quite similar using parts that you can still get; flashes a pair of LEDs for a year with just one D cell:
    http://ourworld.compuserve.com/homepages/Bill_Bowden/page5.htm

    Now, it IS possible to build an LM3909 from discrete components. Rob Paisley shows how on his site:
    http://home.cogeco.ca/~rpaisley4/LM3909.html

    Of course, a "home made" LM3909 will take up more PCB real estate than the IC, but if you really want to emulate the original, there ya go.
     
  5. MIRINGU

    Thread Starter Active Member

    Mar 18, 2007
    75
    0
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