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Re: [Phys-l] CFL's Read the fine print.



Below reminds me of the oddity -- when I wrote many (would you believe three?) years ago I had replaced all w/ CFLs, they included the refrigerator ones. The temp according to a bio. lab. thermometer (in a plastic bottle of alcohol) is ~ 5 C. The delay is much greater at night. It's hard for me to believe the ambient light help in the ionization, yet I don't think the T is any lower at night *. A science faire project?

Obviously the reason for avoiding high temp. is for the e-ballast. I suspect the lamp itself would enjoy 50 C.

* Anecdotal: other (in rooms) lamps appear to have the same behaviour when very dark and not during summer.

bc, sometime kitchen physicist.

p.s. The one in the soffit above our bed requires a loooong time to come to full intensity. Initially it's insufficient to "read by". Later GK complains she wants to sleep.

William Maddox wrote:

From: WC Maddox

This may explain some of the variation in how long CFL bulbs last: On a piece of cardboard where you would see it if looking at package in store it states " LASTS 5 YEARS" in orange letters about 3/8" high. On the back in black print about 1/8" high it states that the 5 years is based on a average use of only 4 hours per day. You are also warned in small print not to use it in an enclosure and that it is guaranteed to start only down to 5 deg F.

What's with the 50 cent CFL bulbs some have mentioned? Around here they are closer to $5.00. I wonder how long a subsidy like this could last.

Does anyone have experience with using halogen screw in bulbs for home use? I wonder how they fit into question about cost, power use, lifetime, brightness, & color.

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