Using the cRIO to control custom lights

[Russ Beavis]

The R and C on your schematic aren't doing anything really useful. You need to add a resistor between SIGNAL and the Base of your transistor.

You'll also need to triple check the specs for the transistor that you've selected and ensure a sufficiently high current-transfer ratio. For example, the transistor has a beta of 100 and you're trying to deliver 1A of current to the LEDs, you'll want to put at least 10 mA (1A/100) into the base of the transistor (by selecting the base resistor accordingly).

You'll probably also need to place a series resistor in your string of LEDs but it's possibly to let the transistor do that "work" for you.

You'll also need to consider heat dissipation. For example, with 1A in the LEDs and 2V LEDs, you'll have 4V across the transistor and/or current-limiting resistor. 4V * 1A = 4W!!! That's a lot of heat to remove (if you're using really strong LEDs, but you may not be dumping 4W continuously).

You could also consider using a FET instead of a BJT. In that case, you'll want a resistor to ground at the gate input to the FET (and maybe a small resistor into the gate).

Russ