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LEDs can be dimmed. It is not as simple as a lamp. I found that if you put a larger than normal current limiting resistor in the circuit, the LED will be dimmed.

I used a DCC function decoder to dim the headlight on a locomotive. It worked just fine.
 

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Yes it seems because LEDs are very directional and looking into the lens it doesn't seem to change that much - but if you look at the beam shining on something it is easier to see the intesity of the light change. If you use a 1K pot and 3.6v and experiment...
 

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Dan - I find that the best way to dim LEDs is with a pulsed DC voltage sometimes called PWM or PWC - I wrote an article about dimming and brightening ditch lights that goes into quite a bit of detail about how this can be done.

You may want to have a look:

http://www.trainelectronics.com/artcles/ditch_lights/index.htm




dave
 

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I had 2 white LEDs in series on a 14.4v battery powered locomotive and wanted them quite dim. I put a 10K resistor for current limiting. They WERE dim. A 1K resistor on 14.4v will dim them but not drastically.
 

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The usual way is to pulse them, as Dave suggests.

The light of an LED is related to the current, not the voltage as the LED will strive to draw as much current as needed to keep the voltage constant.
 
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