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On Mon, 2011-03-28 at 16:19 -0400, Jim Kinney wrote:<BR>
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On Mon, Mar 28, 2011 at 3:53 PM, Greg Freemyer <<A HREF="mailto:greg.freemyer@gmail.com">greg.freemyer@gmail.com</A>> wrote:<BR>
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dimmer's save electricity too unless you<BR>
keep them at max. most of the time.<BR>
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Not sure on that. Most dimmers are just a simple rheostat device (voltage divider). They get pretty warm in use. Some are switches that vary the "on" time to keep the lamp lit. Those will save power. But those also hum badly and provide some nasty noise back into the AC line. Run a speaker cord near a dimmer and listen for the fun.<BR>
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NO! Most dimmers are not simple rheostat devices! They work on an entirely different principle, which is why they do not generally work with traditional (magnetic ballasted T-12) fluorescents. The dimmers work with a diac/triac type device and a toroidal coil to distort the wave form of the AC current. Effectively, the voltage peak the same positive and negative cycles as before, but for a shorter period of time during the 1/120th of a second that each half of the cycle is active. With an incandescent, the filament does not heat as much due to the shorter time and hence less light. On the other hand, a fluorescent tube is 120 ≅200vac lightning bolts a second through a gas comprised of a mercury salt which is gaseous at room temperature (hence the 4vac heaters at each end). Dimming by reducing the duty cycle of the AC allows the mercury to precipitate out of the gas after a short period of time and not conduct the electricity. (which will also happen if you do not make good connections with both pins)<BR>
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The new T-8 fluorescents and electronic ballasts have their own problems with dimming.<BR>
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