RE: LED Lighting

["Rob Mouser" <groups@xxxxxxxxxxxx>]

Ah yes indeed you are correct the pitch changes with the light colour and
dimm level. Which adds to make it all the more annoying!
Really don't fancy re-soldering 30+ iCoves so might need to look at some
sort of enclosure. If I'm clever I can include some sort of reflector which
may help the light disperse.


Many thanks,

Rob

-----Original Message-----
From: Bricknell, Tony [mailto:tony.bricknell@xxxxxxx]
Sent: 31 January 2005 09:03
To: ukha_d@xxxxxxx
Subject: RE: [ukha_d] LED Lighting


The high-pitch whine is due to the way the LED's are dimmed.  Well, they're
not actually dimmed - just turned on and off very quickly, with the on/off
ratio roughly proportional to light output.  Same as a conventional light
dimmer 'buzzing' - only at a higher frequency.  You should hear the whining
change depending on the colour intensity being generated.

How to get rid of it?  I've thought about this and, assuming the noise is
generated by the electrical stresses in the switching transistors (mounted
on the small "control" PCB) and not the LED's themselves, one
could remove
the small "control" PCB from the back of the large LED PCB, and
put the
"control" PCB the other side of a partition wall.  Remembering to
keep the
interconnects as short as possible.  Not actually done it myself yet,
though...  This also assumes you're a dab-hand with a soldering iron.

-----Original Message-----
From: Rob Mouser
Sent: 30 January 2005 21:05
To: ukha_d@xxxxxxx
Subject: LED Lighting


My only current criticism is that the fittings seem to give off a slight
high pitched "whine". I guess its something in the electronics
within
the iCoves themselves? Rather a shame as if you want to "chill
out" it
hardly helps! Anyone got any clues as to what's causing the noise,
anyway to stop it?