Simple 12 Volt Circuit Switch for Motorcycle

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Thread Starter


Joined Feb 26, 2015
Hi all,

Project : Motorcycle headlight conversion to LED

Common H4 connectors used in mc headlights have 3 outputs. The center, 12 volts and the 2 outside negative (ground) from the hi/lo switch. The LED bulb is polarity sensitive. I need a simple circuit switch to change polarity to the bulb. I am thinking transistors, one for each output of the hi/lo switch. The max current needed to power the bulb is 80 watts. The bulb has 3 inputs. Center, negative and the 2 outside need to be switched positive separately. I have limited electrical experience and would rather ask than to do trial and error. My research identifies PNP and NPN type transistors ...... or maybe I need something else. (?)

Hope I explained this properly.
Thank you.


Joined Apr 5, 2008

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