12V Signalling (transistor as a switch)

Discussion in 'The Projects Forum' started by altontoth, Jul 31, 2011.

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  1. altontoth

    Thread Starter New Member

    Apr 11, 2009
    So, I have a circuit that should work, but I'm kinda stuck. I want to drive a strip of LEDs (input 12V, maximum brightness at 0.45A) to use it as a combination tail light / turn signal on my scooter. As such, I want them to be on all the time, and essentially blink off when 12V is applied to the turn signal wire. I'm working on these one side at a time, and a duplicate circuit will be built for the other side.

    The circuit I have now is using a TIP32C PNP transistor, with the emitter tied to 12V (tail light), and the collector going to the LED strips, then to ground. The base has two resistors on it, one each going to ground, and to the 12V (turn signal). I can get the LED's to blink properly, but only if I use resistor values that result in the LED strips only being about 75% brightness. If I use resistors to get the LED strip to full brightness, I can only get them to turn 'off' to about 80% brightness.

    I think the route that I may have chosen is the wrong one, and I'm half tempted to just go buy some 12V relays, but I'd rather not. Help? Thanks in advance!
  2. bertus


    Apr 5, 2008

    I am closing this thread as it violates AAC policy and/or safety issues.

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