Blue wrote:

I talked with a guy in a large department store replacing flourescent bulbs
about the 1-2 problem. He said a failing bulb also extinguished the good
bulb but his procedure was to rather than try to find the bad bulb to simply
replace them both as they are cheap and aged at the same rate so that the
"good" bulb was nearly aged out anyway.



Apples and oranges....

That guy was probably referring to lamps in fixtures where two bulbs are
fed by one ballast. That's not the case with the kind of CFs you describe.

There is no technical reason I can think of relating to the bulbs
themselves which would explain why two CFs fail "about the same time"
other than excellent design life calculations and manufacture with
identical molecules in the same places in all the components of the
bulbs. G

But, possibly the second CF in the event you described was damaged by an
inductive spike caused by the first bulb arcing across the line. That's
more of a cause and effect relating to the type of failure of the first
bulb than it would be a design life factor.

Your "short life" problems are likely due to poor quality bulbs or
something strange about your home's power, like frequent spikes and
surges. I've been using about 15 CFs for over 5 years in various spots
in our home, including in the outside lamps straddling our front door,
and haven't lost one yet.

Jeff


--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."