4/20/17 LED Driver Cards

Quick design note: I’m using 2N2222 transistors (leftover from previous projects) to switch on the LEDs and Annunciator lights. The transistors are on the LED Driver cards. When used with LEDs, there are current limiting resistors in the Collector Emitter junction. These resistors are not used when driving the incandescent bulbs in the Annunciator panel. For the picture below, notice the jumpers on the Collector side. No current limiting needed for the incandescent bulbs.


For some reason the plastic case transistors worked better with the Annunciators and the metal can ones worked better with the LEDs. Also, for the LEDs, I used different current limiting resistors so the red and green LEDs had the same brightness. Base resistor was 10K for the metal can transistors and 1K for the plastic transistors.

Parts for my Dremel tool should arrive tomorrow. Once installed, I’ll start drilling holes for LED holds, switches and Pots.

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