Re: LED Lighting?

["Simon Coates" <simon@xxxxxxxxxxxxxxxxx>]

Yes it's true - but might be more of an issue commercially rather than
on domestic installations.
More of a problem when there are a lot of power supplies.
I've done some jobs in the past where the electronic transformer
individually passed EMI regs but when hundreds were in the same location
the installation as a whole caused problems - both line-borne and
air-borne.
Also done some jobs where lighting power supplies like this are not allowed
- eg. operating theatres and radio studios. They're not allowed for the
very reason you asked.

Regards,

Simon


----- Original Message -----
From: Tracey Gardner
To: ukha_d@xxxxxxx
Sent: 08 March 2009 22:22
Subject: [ukha_d] LED Lighting?



A remark on LED lighting was made on another list that I am a member of.

The remark was as follows,

"One thinks of LEDs as being innocent DC devices fed via a resistor.
But
modern designs often turn them on and off at frequencies in the kHz range,
generating harmonics going into the lower radio bands"

I also imagined that LED lighting was purely DC driven and I'd be
interested
to know if this statement is correct?
If it is correct does anybody have any idea of the frequencies invloved?

Thanks

Tracey





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