Here are NPN bipolar and N channel MOSFET LED drivers. To choose the LED current limit resistor (R4, R5) the formula is: R = (Vsupply - LED Vf) / desired LED current. Vf is the forward current from the data sheet (1.5V). The max current for the 2N7000 is 200mA, 600 mA for the 2N2222.
