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OR Gate for 12 light circuit

Discussion in 'The Projects Forum' started by kpgraci, Jul 30, 2010.

  1. kpgraci

    Thread Starter New Member

    Jul 30, 2010
    Hi all,

    Novice, I've built projects before, never designed one.

    I have sailboat with a light composed of two independant 12vdc white LEDs (I think they are leds) (L1 and L2 in attachment).

    I have a SPST switch S1 that should turn on both lights, and a SPST switch S2 that should turn on only L2.

    I propose to insert a diode D1 as shown to prevent L1 from turning on when S2 is closed.

    Will this work? Do I need anything else? :confused:

    For a 12VDC (car battery) what Diode would D1 need to be to handle the power?


    PS - I know this can be done with a DPDT switch and wiring only, but I need it to go through a fuse panel with only SPST switches.
  2. KMoffett

    AAC Fanatic!

    Dec 19, 2007
    Yes, it will work. What is the wattage of L2. That will determine what diode will be needed.

    The two SPST switches could be replaced with one SPDT/Center-OFF switch.

    OOPS, missed the PS

    Last edited: Jul 30, 2010
    kpgraci likes this.
  3. Bernard


    Aug 7, 2008
    If L1 & L2 are LED's, then do not forget to add current limiting resistors. Need L specs.
  4. windoze killa

    AAC Fanatic!

    Feb 23, 2006
    I think the OP is only showing the LEDS as single unit when they are actually commercial lights already installed. He just wants to switch them differently.