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This is Bugging Me

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jeff_wisnia

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Jan 6, 2011, 11:48:34 AM1/6/11
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About 10 years ago I installed "touch dimmers" inside four metal bodied
table lamps in our home. We really like them because they eliminate
fumbling for a small switch on the lamp base or bulb socket.

The dimmer in the lamp I sit next to while reading died a few months ago
and I replaced it with a new one, a different brand than the originals.

After installing the replacement that lamp would occasionally shut down
or jump to a different intensity level without my touching it. It would
happen perhaps once a week.

I tried tapping the lamp and its shade with a rolled up magazine to see
if I'd messed up an left a "loose disconnection" somewhere when I
installed the replacement touch dimmer, but that didn't have any effect,
the dimmer stayed where it was set.

Thinking the problem might be caused by line spikes I tried reversing
the non polarized line plug to see if that would make the problem go
away. It didn't.

Last night I found out the cause.

There was a small beetle like flying insect buzzing around inside the
lamp shade and when I saw it bump into the metal body of the lamp the
dimmer shut off. It bumped it a second time and the dimmer came on at
its first intensity.

The bug landed on the wall and I quickly sent it to its reward.

What I don't understand is how a tiny bug like that could have enough
body capacitance to activate the dimmer.

Maybe flying around creates enough static charge on its body that when
it touched the lamp there's enough discharge to trip the dimmer.

Has anyone else ever experienced this bugging of a touch dimmer?

Thanks Guys,

Jeff
--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10e12 furlongs per fortnight.

William Sommerwerck

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Jan 6, 2011, 11:52:19 AM1/6/11
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> I tried tapping the lamp ... with a rolled-up magazine...

Naughty lamp. Naughty lamp!


> What I don't understand is how a tiny bug like that could have
> enough body capacitance to activate the dimmer.
> Maybe flying around creates enough static charge on its body
> that when it touched the lamp there's enough discharge to trip
> the dimmer.

That sounds plausible. Helicopters develop a very high static charge.


Michael Kennedy

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Jan 7, 2011, 2:17:34 AM1/7/11
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"jeff_wisnia" <jwisniaDu...@conversent.net> wrote in message
news:ig4rq1$4v4$1...@news.eternal-september.org...

It was a flying capacitor not a beatle.

Jeff Liebermann

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Jan 7, 2011, 11:35:20 PM1/7/11
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On Thu, 06 Jan 2011 11:48:34 -0500, jeff_wisnia
<jwisniaDu...@conversent.net> wrote:

>What I don't understand is how a tiny bug like that could have enough
>body capacitance to activate the dimmer.

It's not capacitance. The dimmer switch acts on changes to the amount
of 60Hz hummmmm that it picks up. Anything that abruptly changes the
amount of hum will cause the switch to trip. The bettle is apparently
slightly conductive (mostly water) and acts as a slightly larger
antenna for the dimmer switch. When you get close to the switch with
your hand, it's the capacitance between your body and the switch which
increases the hum level. When something actually touches the switch,
it's conduction, which has a greater effect than capacitance.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com je...@cruzio.com
# http://www.LearnByDestroying.com AE6KS

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