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Potentiometer
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cholin:
This is a quick question answer situation.
ChadTower:
Any pot that can handle 5v or greater will work.  If you go a ton higher than that, you'll simply see the max brightness be farther and farther from the end of the range.
BobA:
The proper way to configure your LED for dimming is to put the proper resistor in series with the LED and POT.  That way the minimum resistance when your POT is at 0 Ohms is the resistor.  The value of the pot should be about double the value of the resistor to give you a range of dimming.   If your 5V led is made to work with 5V without a series resistor then you might have to experiment with a 100 or 200 Ohm pot.  Remember if you need a limiting resistor and you use only a pot you can fry the LED.  At minimum resistance the pot will allow more than max current to flow and you LED will pop.

BobA
cholin:
I will have a resistor, heres a picture of what I want, this way I just want to know which potentiometer can output 5v MAX, 0v MIN when 5v is supplied.
BobA:
Any pot can do that because it goes from 0 ohms to max res of the pot.  If you size it at 50 ohms then the max resistance of you circuit will be 100 ohms and the min resistance will be 50 ohms.   When the pot is at 0 ohms it has a OV drop and thus your circuit gets the full 5 V.   

If 50 ohms resistor will allow your LED to have max current then a 50 ohm pot will cut that in half.  A 100 ohm pot will give you about a third.  However since light output is not proportional to current you will have to try one to see if it give you what you want.  A 1000 ohm pot will for sure make sure your LED does not have any light output for about 3/4 of its range and thus the pot will probably only work in about 1/4 of its rotation. From No LED to Full Brightness in less then 1/4 of a turn.

BobA

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