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Re: [APD] Fw: DIY reflector?

On Thu, 20 Jul 2006 12:22:12 -0700 (PDT), "S. Hieber"
<shieber at yahoo_com> wrote:

>An advantage of an electronic ballast operating at 15k-80kHz is that the on/off cycling is in no way perceptible. Also, any man over 40 would be lucky to be able to hear a hum in that frequency range.  ;-)

Unfortunately, I hear the high frequencies too well.
Odd, but true. With hearing aids, though, I wouldn't
notice something that high since I would hear the lower
frequencies much louder. 

Television picture tube scanning guns (somewhere in the
15 khz range) used to drive me nuts. I could hear them
through windows and tell that a TV was on even if the
sound was muted. Now I'd have to be a lot closer to the
TV to hear it. 

With those electronic ballasts, it would be very easy
to stabilize them mechanically, which is the problem
with the 60 cycle ballasts. If the laminations of the
ballast transformer get loose from the iron core, they
buzz like crazy. You can sometimes fix this, but it's
not worth the trouble in most cases.

Imagination is more important than knowledge.
   -Albert Einstein

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