I would like to create a circuit that I can dim an LED with a potentiometer. Here's the circuit: The problem is I don't know what values to use for the components. I'm not sure how much voltage and current I need to supply to the transistor. I am familiar with Ohm's law, but I don't' understand the current gain(hfe) or the saturation voltage on transistors. The reason I'm using a transistor in the circuit is because the one LED shown will actually be some arrays of LEDs with a power draw of around 2W. If somebody could explain to me how to figure out the correct component values, I would really appreciate it!