LED Noise

[Norman CYYJ]

Have any of you figured out how to get rid of the high frequency noise generated by the current generators in the MR-16 LED lamp? I am using them for landing/taxi lights and they wipe out the comms.

[elippse]

What kind of wire are you using to sevice them? Is it a single wire with return through the wing and fuselage, or shielded-twisted pair. If it's the former, I would recommend replacing it with the latter. These LEDS use a pulse width modulator/inductor voltage converter which generates lots of harmonics. When unbalanced conductors are used on the pulsating power lines they will radiate. Usually if the circuit has sufficient capacitance on the power input there will not be transients flowing on the power wires. But if the circuit doesn't have good filtering on the power leads, the next best bet is to use the STW. Twisted pair wires carrying equal and opposite pulsating currents which generate opposing magnetic fields which will essentially null out any radiated fields. Having them contained in an overall shield grounded at the power source adds additional isolation.

[CharlieWaffles]

Ever find a solution to the noise issue?

[Dean_aeroleds]

I recommend that you put a PI filter in line with the power line that runs to the lights. A PI filter is made up of an inductor (also called a choke) with capacitors to ground on both sides of the inductor. The PI filter should go as close to the light as possible.

I would suggest you consider putting a 100uH choke (inductor) inline with at a 1uF ceramic capacitor from the power line to ground on each side of the choke. That will eliminate the high frequency conducted component. Make sure the current rating of the inductor is high enough for the load.

For low frequency audio noise, a 100uF to 1000uF electrolytic capacitor does a good job of filtering conducted noise.

Dean Wilkinson
CTO, AeroLEDs LLC

[Brantel]

The filter Dean mentions above is similar to the one that I worked with Aeroelectric Bob on to develop. He now sells them as a commercial product.

Schematic at the end of this document:

https://matronics.com/aeroelectric/C.../9051-700A.pdf

This totally rid my system of noise produced by the constant current driver used on my home built Nav lights.

[glenn654]

Is anyone using the LEDs made for replacing the incandesant bulb in nav lights?

Do these make RMI noise?

I just installed a set of these during my annual and haven't tested them yet.


Glenn Wilkinson

[lmuelly]

I just changed my wing tip lights over and the noise is terrible! Drives the squelch crazy.

[Canadian_JOY]

In this case, the SEARCH feature is your friend. There have been multiple threads discussing LED lights and much discussion about taming their power supply noise. Grab a cup of coffee, enter the search terms "LED noise", put your feet up and read awhile!