switching led's

Discussion in 'The Projects Forum' started by MJL, Mar 17, 2010.

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  1. MJL

    Thread Starter New Member

    Jul 1, 2009
    This may be too easy for some of you, but I have been looking at things and thinking most of the morning.

    What I want to do is have one LED with both a steady signal, and a pulsing signal. It would have to be able to show a steady signal, or a pulsing signal, or have the pulse override the steady signal. (turn signals on a car)

    I've looked at using relays, scr's scs's, and transistors. This is what I've come up with. Can someone tell me if it will work, and if not, why?


  2. Bernard

    AAC Fanatic!

    Aug 7, 2008
    Should work. Pulse off= ground, + P on= B+[ +12V?], steady ,switched to ground. Resistors & transistors depend on how many, and what kind of LEDs used.
  3. retched

    AAC Fanatic!

    Dec 5, 2009
    My thought also.

    You would send the "blink" signal to a NC relay on the cathode of the LED. So when the blink signal comes in, it breaks the ground connection and regains it with each cycle, causing the LED to blink.

    Because the relay is Normally Closed, with no 'pulse' it would stay lit.
  4. SgtWookie


    Jul 17, 2007
    This sounds like a scheme to control brake/turn signal LEDs.

    We've stopped supporting those kinds of projects due to the safety issues.
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