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From: random@cbnewse.att.com (David L. Pope)
Newsgroups: sci.electronics
Subject: Re: light bulbs buzz when dimmed
Message-ID: <1991Apr3.223655.18202@cbnewse.att.com>
Date: 3 Apr 91 22:36:55 GMT
References: <1991Apr2.162037@maximo.enet.dec.com>
Organization: AT&T Bell Laboratories
Lines: 15

> an annoying buzz when dimed.  Is there a better circuit for dimming
> the bulbs that will prevent that !@#$%^&*&^%$# buzz?

Yes, but since the buzz is being caused by the fillament vibrating
at line-current frequency, it would involve a d.c. supply which
would require a little engineering (to determine d.c. power max
and min for the bulbs you are using). The actual cause of the buzz
is the length of the fillament in the bulbs, so maybe you could
find large diameter bulbs designed for dimming (that is, with short
fillaments).

	Good Luck,
	
		Random