Relay I/O Current

[Al Skierkiewicz]

Mike,
R39 F relates to powered devices, which in the case of the DSC is the servo outputs with the jumper in place to feed 6 volts to those outputs. The digital I/O and relay outputs cannot sink or source enough current to feed LEDs without a driver of some sort. If you look at the schematic for the DSC, you will see that the relay outputs feed a small LED in parallel with the relay output. The output current on that LED and the relay drive about max out the chip capability of 16 ma per output. The LEDs on the board are low current devices speced at 5 ma each.