Over the past few days I've been wiring the EFIS CAS warning & caution LEDs. I elected to power them from the GEA24 J244 connector - pin 50. That's a general purpose, regulated, 12volt supply that is limited to 50mA current. In order to remain well & truly below that limit with both circuits activated, I installed a 1.2kΩ resistor in series with the 2 LEDs on each circuit. The current of each activated circuit is shown below (slight difference in value due to differing forward voltages of the LEDs) so with the total being less than 20mA, I'm satisfied that power supply can handle the load. 10mA is also a conservative current for these particular LEDs.
I've also wired the TCU isolation switch along with the TCU warning & caution LEDs. As these lamps are powered from the TCU and subject to main bus voltage, I've sized the resistors to limit the current to 10mA per LED at 14.8V. The forward voltages of the red & amber LEDs are slightly different so I have used a 900Ω resistor on the red warning LED & a 820Ω on the amber caution LED. The amber LED is very slightly dim at 12V but bright enough at 14V, the brightness of the red LED is fine at the lower voltage.
