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Potentiometer to dim 12v bulb?

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New Member
I am going to use automotive, 12v bulbs for a special project of mine and have a couple of questions on how to dim the bulbs with a potentiometer. The bulbs are these: GE Lighting 194NA Automotive Front Sidemarker Light Amber Miniature Bulb (44859) 10 Lamps per Tray

My question is...

1. Seeing that these bulbs are 3.78 watts, do I need to make sure that the potentiometer I use to control the voltage into the bulb is at LEAST a 4 watt potentiometer?

2. How many Ohms should my potentiometer be?

I was looking at these potentiometers: http://www.mouser.com/Search/Refine....355+4294576007 but I cannot figure out which one would do the job for me.

BTW, the bulbs will be assembled parallel to each other.

Thanks for the help!




Here's the simplest PWM circuit I know of, it'll work with the NE555 but it probably won't be as good.


New Member
As an alternative. Dashboard Illumination control rheostat? That's if can find one from a car scrapyard on a car that's old enough.


Active Member
You mention "parallel" - keep in mind that the current for each bulb must be handled - so the number of bulbs will determine the power - if all powered from the same control.
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