Rugged LED Brake Lights

    April 9, 2009
    OK, here's a simple circuit that was by requested by a reader. Normally, I don't like to run too many LED's in series because if one dies, the whole string goes out. Finding the dead one can be bit problematic as well. So, in this design, Super Bright red

    Rugged LED Brake Lights

    OK, here's a simple circuit that was by requested by a reader. Normally, I don't like to run too many LED's in series because if one dies, the whole string goes out. Finding the dead one can be bit problematic as well. So, in this design, Super Bright red LED's designed to run at 40mA were used. But to decrease the chances of failure, I'm only running them at 20mA. If the ON voltage of the LEDs is 1.8 volts, then the value of the current limiting resistor is:

    R = (12-(5*Vled))/Iled
    R = (12-(5*1.8))/.02
    R = 150

    The power being dissipated by this circuit is:

    P = E*I
    P = 12*.02*5
    P = 1.2 Watts

    If you want more lights, just continue to add additional ladders of the resistor and five LEDs

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