Hello: These are waveforms that I measured from a 12VDC LED light! I would suspect that there is a FCC Part 15 issue here. All 3 LEDs in the package exhibited the same issue. Another brand just turned on without oscillation as you would expect.

 

How do you want to treat this problem?

Is the noise causing any problems?

 

These were not cheap led lights I bought them from Ace Hardware.
I powered them with a good quality bench power supply, and used a good quality digital scope.

The bulbs are generating a waveform that is approx 1.6Mhz at nearly 6vPk-Pk. I powered them with my bench PS set to 12VDC and current limited to 2Amps. The bulbs are rated for 12Volts AC Or DC and draw 0.400ma.

The package has the FCC pt 15 notice printed on it. I do not have the equipment to verify if they conform to Pt 15, but I would not be surprised if they do not.

These lights seem to be the only brand that exhibit this. I have tested 2 other brands both dimmable and non dimmable and they all power up a you would expect them to. When they are off the voltage across them is 0V and when they are on the voltage across them is a straight line 12V.

I can't say that they are causing ME. any problems, but there are several reports...
Are LED Lights Causing VHF Radio Interference - BoatUSBoatUShttps://www.boatus.com › expert-advice › february › are...

 

Certainly the power supply portion s of LED lights can be a problem, and have resulted in a lot of legal actions. So you are not alone in the situation. Has the noise caused you any problems yet?
Adding external filtering components can reduce the conducted noise quite a bit, but it does not stop the radiated noise.
Have you gone back to the hardware store and let them know?

 

I returned them but I do not think the person at the cash register comprehended the issue.

I suppose that I should try and contact someone who cares.

The EMI has not caused ME any problems as I bought (amazon) some lights that did not have this issue.

 

You could notify the manufacturer. I might have been helpful if you had kept an offending lamp for them to inspect.

 

These were not cheap led lights I bought them from Ace Hardware.
I powered them with a good quality bench power supply, and used a good quality digital scope.

The bulbs are generating a waveform that is approx 1.6Mhz at nearly 6vPk-Pk. I powered them with my bench PS set to 12VDC and current limited to 2Amps. The bulbs are rated for 12Volts AC Or DC and draw 0.400ma.

The package has the FCC pt 15 notice printed on it. I do not have the equipment to verify if they conform to Pt 15, but I would not be surprised if they do not.

These lights seem to be the only brand that exhibit this. I have tested 2 other brands both dimmable and non dimmable and they all power up a you would expect them to. When they are off the voltage across them is 0V and when they are on the voltage across them is a straight line 12V.

I can't say that they are causing ME. any problems, but there are several reports...
Are LED Lights Causing VHF Radio Interference - BoatUSBoatUShttps://www.boatus.com › expert-advice › february › are...

First, FEIT lamps may not be priced cheaply but they are definitely manufactured cheaply. They lie between good lamps and junk ones on the spectrum.

Second, an AM broadcast radio should receive the signal you believe may be problematic. You should try that.

 

If I still owned a AM radio, I would try it. I haven't used a AM / FM radio in the house (except for FM in the car) in years. I will see if I can borrow one somewhere. I am kinda surprised that ACE hardware carries them. I left a complaint with the manager... Will see if anything comes of it.

Would it do any good to contact the FCC? I would think that the fact that FEIT prints the FCC pt 15 statement on the package would prevent this.

 

How did you measure this noise? what was the setup?

I'll bet you could get the same results with many types of modern LED lights that actually pass EMI tests.

 

Would it do any good to contact the FCC? I would think that the fact that FEIT prints the FCC pt 15 statement on the package would prevent this.

If this is just a few lamps from a single batch neither the FCC nor the manufacturer will get very excited over it. If this is a widespread problem, mentioning it to the FCC and letting many others mention it should bring the problem to resolution. You no longer have the lamps, and you don't have a responsibility to society to remedy this beyond, if you are willing, to bringing it to the manufacturer's attention.

 

I guess that I will leave this to others.

 

Since it is a 12 volt DC bulb replacement, it may be that it is intended for automotive application. Those devices have a different set of standards, at least they used to.

 

Sorry I thought that I specified them.
https://www.acehardware.com/departm...VsQx9Ch3IVAiPEAQYAiABEgJKfPD_BwE&gclsrc=aw.ds

 

OK, my error. Not automotive lights. Or maybe they are. Certainly not the ones I expected.

 

Not automative.

These are the kind of lights one would use in tract lighting.

Please understand that I am NOT claiming that there is anything wrong with them, only the waveforms that I observed on my scope were not what one would expect. Also I tried 3 others of the same make from a different package and they exhibited the same weird waveform. Not what one would expect from a light bulb.

Also as I also stated the same type of lights of another brand did not exhibit these waveforms, they just went form 0v to 12v as you would expect a light bulb would do.

As these bulbs are also rated for AC operation and they exhibit the same RFI like characteristics when powered with 12VAC 60Hz

As you would expect in verifying any such observation, an independent verification would be good.

For this reason, I have returned the product and am not really interested in making any more observations.

I do know that I will no longer purchase this product.

 

These were not cheap led lights I bought them from Ace Hardware.
I powered them with a good quality bench power supply, and used a good quality digital scope.

The bulbs are generating a waveform that is approx 1.6Mhz at nearly 6vPk-Pk. I powered them with my bench PS set to 12VDC and current limited to 2Amps. The bulbs are rated for 12Volts AC Or DC and draw 0.400ma.

The package has the FCC pt 15 notice printed on it. I do not have the equipment to verify if they conform to Pt 15, but I would not be surprised if they do not.

These lights seem to be the only brand that exhibit this. I have tested 2 other brands both dimmable and non dimmable and they all power up a you would expect them to. When they are off the voltage across them is 0V and when they are on the voltage across them is a straight line 12V.

I can't say that they are causing ME. any problems, but there are several reports...
Are LED Lights Causing VHF Radio Interference - BoatUSBoatUShttps://www.boatus.com › expert-advice › february › are...

Hi,

Yes I have read about some of these now. In some ads they make the distinction that they do not cause any RFI for radios and stuff like that. They obviously use PWM drivers.
A neighbor bought new LED headlights and they caused the radio to go bonkers.
The LED headlamps I purchased did not bother the radio at all, so I was lucky because I didn't think of that at the time I got them.

 

Consider this analysis: The power supply that you used is probably less than perfectly regulated, and so as the current varies rapidly the voltage also varies a bit. In addition, the connections to the bub may have a bit of resistance. And the picture of the scope trace does not indicate much at all, as we have no hint about the actual test setup, nor the actual magnitude of the waveform. And published ratings are not to be taken as true unless verified.
So I am guessing that what you are seeing is the effect of the current variations on the terminal voltage.
What we do not have is any statement of the measured terminal voltages on the bulb terminals, any hint as to the actual supply current, nor any indication of the noise contributed by the power supply. What does the voltage across a 27 ohm resistor look like? It might be a noisy supply, very stable but noisy. Or there might be an excessive voltage drop in the connection leads.
Without an adequate knowledge of the test setup the results may not be what we think they are.

 

I am away from my bench right now. Give a day or two to respond.

 

My point ultimately being that it is most likely the current variations of a switching power supply. And by the way,switcher supplies do generate more noise on the input connections.

 

I returned them but I do not think the person at the cash register comprehended the issue.

I'm quite certain the clerk did not "comprehend" the issue. If they did - that would be a rare occurrence and one would have to wonder what they're doing working in a store instead of an electronics company. We understand it because we've been in the industry for many years. Even still, some here actually don't understand (comprehend) the issue.

I'm surprised at MrAl's comment about LED headlights causing AM interference. I never heard of that before. And would not have expected that.