I have been experimenting with the white LEDs for exactly this purpose.
They produce a very nice, white light and run extremely cool. They are a
little expensive but the prices are coming down gradually.
Here's a link to a good supplier that I've purchased the LEDs from in the
past:
www.allelectronics.com
and specifically a white LED:
http://www.allelectronics.com/cgi-bin/category.cgi?category=340&item=LED-75&type=store
This one is a 3000 mcd (milli-candle) with about a 15 deg view angle and
sells for $2.00 each
The biggest problem is that they are fairly directional as opposed to a
normal incandescent bulb. This means that the LED placement has a
considerable effect on where the light goes within the gauge. I was hoping
to bundle a couple or 3 LEDs together in a screw-in base along with the
required resistor to make a direct replacement "bulb" similar to the ones
found at this commercials site:
http://www.theledlight.com/dcbulbs.html
I've tried it with a single LED only to keep the cost down and was a bit
disappointed in the amount of light actually reaching the front of the
gauge.
The other thing I've played-around with is positioning the LEDs under the
front 1/2 bezel on the small gauges and thus illuminating the gauge face
and needle. This seems to work well but the large gauges will need some
more thought for an approach like this.
Joe Parlanti
B382000026
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