"Magnetic ballasts modulate electrical current at a relatively low
cycle rate, which can cause a noticeable flicker. Magnetic ballasts may
also vibrate at a low frequency. This is the source of the audible
humming sound people associate with fluorescent lamps.
Modern ballast designs use advanced electronics to more precisely
regulate the current flowing through the electrical circuit. Since they
use a higher cycle rate, you don't generally notice a flicker or
humming noise coming from an electronic ballast. Different lamps
require specialized ballasts designed to maintain the specific voltage
and current levels needed for varying tube designs."
more about flourescent lights at:
Like others said, its the ballast
The metal core pieces are vibrating probably due to a loose housing.
Some of the old ones that were held together with a metal piece that
goes around 3 sides can be quieted by squeezing that metal piece.
Otherwise, replace the ballast, but first price a new fixture. Many
times the fixture costs less than a ballast.
On Thu, 16 Feb 2006 02:54:15 -0600, snipped-for-privacy@UNLISTED.com wrote:
One could then donate the old fixture to someone who wouldn't mind the
humming, like a factory or a band without a rhythm section.
Remove NOPSAM to email me. Please let
me know if you have posted also.
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