This interesting.
I've been switching o LED Christmas lights and was originally worried
about RFI. I"m not certain how these work: Some provide FWB
rectification while others provide only have-wave rectification. But,
it's obvious that these don;t have a built-in PS. As far as I can tell,
these things are RF-silent. I hear no change at all when I turn them on.
LED light bulbs are different because they have their own switching PS
inside. I've used mainly Phillips, a few Cree and couple of no-names
and, so far, haven't heard a thing form them. I've also replaced
fluorescent tubes with LED equivalents and they're also quiet (both the
kind that requires wiring around the ballast and the kind that will use
a SS ballast). The same goes with CFLs. Sounds like I should thank my
lucky stars!
Kim N5OP
On 8/15/2017 6:25 PM, Jim Brown wrote:
I suspect the RFI problem is caused by a poor quality power supply, or
the use of AC to drive the LED directly. I've used a lot of the LED
strips that Wired Communications sells at hamfests, mostly in the
western US. I use five of them to light my shack, powering them from
the 12V battery that is float-charged from a linearly supply.
Last month, I mounted two strips on a shelf to light the area around
my computer desk, and, by accident, grabbed a 12VAC wall wart (in
other words, just a transformer) to power them. The RF noise was VERY
strong. Replaced the transformer with a 12VDC linear supply and the
noise went away.
Of course, a switch-mode power supply would also generate noise.
73, Jim K9YC
On 8/15/2017 4:08 PM, Ken Winterling wrote:
I have also heard some reports that the fluorescent or LED bulbs in an
opener can cause trouble with electric car door locks. Some folks had
difficulty locking/unlocking their car doors while the opener lights
were
lit.
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--
Kim Elmore, Ph.D. (Adj. Assoc. Prof., OU School of Meteorology, CCM, PP
SEL/MEL/Glider, N5OP, 2nd Class Radiotelegraph, GROL)
/"In theory there is no difference between theory and practice. But, in
practice, there is." //– Attributed to many people; it’s so true that it
doesn’t matter who said it./
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