Potentiometer to dim 12v bulb?

[HondaCop]

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: **broken link removed**

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!

Regards,

HondaCop

 

[Nigel Goodwin]

Don't use a crude potentiometer, use PWM to dim it - a crude potentiomer will be expensive, large, and get VERY hot.

 

[Hero999]

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

 

[marcbarker]

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

 

[stevez]

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.