[vcf-midatlantic] OT: LED lights

Dave McGuire mcguire at neurotica.com
Fri Mar 11 10:47:06 EST 2016

On 03/10/2016 06:08 PM, Dan Roganti via vcf-midatlantic wrote:
>>> ​From what I've seen
>>> only the 'dimmable' LED bulbs have RF pollution, not plain LED bulbs
>>> ​Dimmers in general create this problem too, even with incandescents.
>>> ​So even if you buy plain LED bulbs and your room is wired with a dimmer,
>>> You still have a problem - even thought the LED bulbs will not dim.
>>   The non-dimmable ones still use high-frequency transformerless power
>> supplies.  I've not measured one myself, but I'd be shocked if they
>> didn't radiate quite a bit of EMI/RFI as well.  Are you certain of this?
> ​oh yea, nothing has zero percent emissions.

  Of course.  But most anything will have more than an incandescent bulb.

> I checked my plain LED bulb again and it only happens if I put it right up
> against the radio.
> And again the radiated energy is minuscule.
> ​But the dimmable LED bulbs have several orders in magnitude of energy.
> They are very distinguishable from a distance.

  My EMI pre-compliance test setup is nearly ready to roll.  I should
get some representative LED bulbs and put them in the test chamber to
see what their emissions profiles look like.

> So much so, you wonder why they don't require a FCC part 15 class B
> Besides, any home micro over there built before the 1979 FCC reg's would
> very likely not pass this either.
> So you can still have a problem.

  I think a great many Chinese companies are skirting past the FCC


Dave McGuire, AK4HZ
New Kensington, PA

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