[ale] OT: Disposal of standard fluorescent lamps?

[Jim Kinney]

Thanks! I haven't disassebled an old school dimmer in a long time. The
physics has changed
Good description of why and how.
On Mar 31, 2011 10:38 PM, "Chris Ness" <luxomni at earthlink.net> wrote:
> On Mon, 2011-03-28 at 16:19 -0400, Jim Kinney wrote:
>
>>
>>
>>
>> On Mon, Mar 28, 2011 at 3:53 PM, Greg Freemyer
>> <greg.freemyer at gmail.com> wrote:
>>
>> dimmer's save electricity too unless you
>> keep them at max. most of the time.
>>
>>
>> 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.
>>
>
> 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)
>
> The new T-8 fluorescents and electronic ballasts have their own problems
> with dimming.
>
>
> --
> mailto:luxomni at earthlink.net All jobs are equally easy to
> http://luxomni.blogspot.com the person not doing the work.
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