Dimmer Control

[s24789]

I have changed plans yet again on panel lighting. Looking for guidance on a dimmer. I already have a 50K 2W pot I was going to use for another option. I am switching to an under the glareshield LED option. The LED lights only draw 83ma at 12V. Is this pot useable or do I need a dedicated dimmer system. Thank
Kevin

[cfiidon]

LEDs need a threshold voltage to operate, so unlike incandescent bulbs you need to control the light intensity by controlling the duty cycle of the power. This is done with pulse width modulation, basically switching off and on and controlling how long it's on by how long its off.

I'm using a four channel controller (http://www.aircraftspruce.com/catalog/elpages/lc40.php), but you can find less expensive ones by searching the web.

Don

[prkaye]

I'm pretty sure my cabin lights from Stein are LED and I used Vans' cheap dimmer circuit and it seems to work fine
http://www.vansaircraft.com/cgi-bin/...product=dimmer

[elippse]

Originally Posted by s24789

I have changed plans yet again on panel lighting. Looking for guidance on a dimmer. I already have a 50K 2W pot I was going to use for another option. I am switching to an under the glareshield LED option. The LED lights only draw 83ma at 12V. Is this pot useable or do I need a dedicated dimmer system. Thank
Kevin

Several years ago I designed a PWM dimmer circuit for someone, and if you're interested I could dig it out. One of the considerations you should make about your lighting is this, are you going to make the positive or the negative voltage source common to the lights and control the other source. I recommend that you make the negative source common and control the positive. That way if the common lead gets shorted to the airframe there is no problem, and if the positive lead is shorted it will pop the breaker.