Simple constant current source (CCS) to drive one ore more LEDs
This circuit is a simple constant current source to drive one or more LEDs based on a LM317 and some additional components.
I´m using this circuit on my Mikrokopter to drive 4 Rebel LEDs with a total current of 400mA .
Dependent on the current drawn by the load it is highly recommended to use a heatsink for the MJE15030 or fix the whole PCB to a heatsink. An alloy based PCB would be even better.
Electronic circuit (Click for better resolution)
Components (Click for better resolution)
Layout (Click for better resolution)