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Hey Guys.

I tried to install an LED lamp on my panel to let me know when I'm transmitting on my comm radio but it's not working. I have a Trig comm and it already has a little "T" that lights up when I push the PTT button on my stick so I know I wired that correctly. I'm one of those guys that had an embarrassing situation with a student when my PTT switch got stuck on early in a lesson. The guys in the tower where not pleased after I landed and I'm sure a lot of other flyers weren't either! Of course I never want it to happen again! That little "T" on the Trig doesn't stand out nearly as well as an LED lamp.

I think I wired the lamp correctly in parallel. I've tested the lamp separately and it works. Maybe it doesn't draw enough juice to light? The "T" light seems to have a short delay where I think it should be instantaneous. I'm not an electrician so let me stop here.

My questions are 1: Can I wire an indicator light and 2: If so how is it done?

A simple way would be to use a double pole PTT. Power the LED via the second pole.

Peter

peter anson wrote:A simple way would be to use a double pole PTT. Power the LED via the second pole.

Peter

With one in each stick, so they can power the LED in parallel.

John

Generally PTT switches provide a path to ground for an internal switch in the radio for transmit. You should be able to use your existing switch and wire an indicator. I've attached a drawing. If your indicator is an individual led, then you would need a current limiting resistor to keep the current to around 20 milliAmps. Assuming 13.8 volt aircraft power, a 680 ohm resistor would do the job. If your Led indicator is a self contained unit in a housing that can be hooked to 12 volts, then the current limiting resistor is not needed. If you are using an incandecent bulb, then make sure it is rated for 12v dc power. No resistor needed for that application. Its important to know that Leds have a plus and minus side (Anode and cathode). The minus side must be the side attached to the switch and plus side attached to power.

Thanks Gregg!!!