[Elecraft] CFL

[Stephen Prior]

Jack,

I believe some (not all!) Chinese companies might think that CE means
Chinese Export!

73 Stephen G4SJP




On 18 November 2012 20:54, Jack Smith <jack.smith at cliftonlaboratories.com>wrote:

> The CFL's I've analyzed and disassembled have small switching power
> supplies, usually running around 40-50 KHz.
>
> If you are a VLF/LF listener, you can see the emitted signals up through
> several hundred KHz. Many sidebands can be observed, at multiples of 60
> Hz from the central frequency (which is unstable).
>
> Usually, though, not much can be heard about 1 or 2 MHz if your antenna
> is separated by a few tens of feet from the lamp.
>
> If you have a defective CFL, disassembling it can be educational. First,
> you will see many components stressed at or above their maximum ratings.
> I've seen some with the filter caps operated with voltage above the
> maximum rating.
>
> Second, it's not uncommon to see the PCB with holes and traces for EMI
> filtering, but the parts are not installed. I assume that the parts are
> installed in some prototypes to meet EMI specifications and then are
> omitted to save money.  I don't believe the CE approval markings mean
> anything to the Chinese manufacturers.
>
> I've written a bit about CFLs at
> http://www.cliftonlaboratories.com/compact_fl.htm
>
> Jack K8ZOA
>
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