How to dimm a LED?

[Geroximo]

Hi mates,

How do I dimm a LED?
Not a keyboard LED, but a LED which I want to use for ambient light.

I want to use a single LED diode to ambient light my keyboard drawer and power it through USB.
The light should be very dimm.
How can I achieve that?
Just use a stronger Resistor?

[Tactile]

To reduce the brightness, you're right - a larger resistor value.

To make it variable brightness requires extra circuitry.

[Geroximo]

Thank you very much.

[tp4tissue]

Thank you very much.

It's called PWM

[rowdy]

Thank you very much.

It's called PWM

Thank you for making me finally research how PWM actually works

[noobas4urus]

A simple potentiometer should work. It's a variable resistor, so it will work like a dimmer switch that can change whenever you'd like without changing the circuit.

[Tactile]

A simple potentiometer should work. It's a variable resistor, so it will work like a dimmer switch that can change whenever you'd like without changing the circuit.

Yes, but it should have a resistor in series to ensure that the minimum resistance when the pot is turned down does not go outside the LED specs. I've zapped a few LEDs and I don't like that plastic smell they emit when they fail. 

[notbrain]

If you don't want to go the resistor route, you can also just coat the LED in some transparent black paint. Or a trick from my modeling days is to get some dark nail polish and don't mix it--use the clear dark liquid as paint or mix a small batch of transparent by separating out the color and extra base (clear). You can dim more by adding coats until it's as you like it.