"Steve Kraus" wrote in message
nk.net...
I'm using one with an electric timer, not an electronic one.

But I thought both were either totally off or totally on. I don't see
how they could damage the bulb. The electric one at least just has a
mechanical switch controlled by a moving wheel.

That's fine. What you want to avoid is anything where the power switching
is done electronically like with a triac. Even that would probably be ok
if you could be sure that it passed the full waveform when on but unless
you put a scope on it you may not know. Light dimmers fall into this
category...their dimming action is due to not passing the full waveform.

Some but not all photoelectric switches work this way. I have one like
that and it was notable for turning a lamp (regular incandescant) on and
off gradually--as daylight changed--it dimmed the bulb up or down. I
recently replaced it with one that was full on / full off with an internal
relay. I suppose there may be some electronic timers designed
specifically
for incandescents lights that work the same way. But if the electronics
drives a relay to do the actual switching, or certainly an
electromechanical timer, will be just fine.

That last sentence if dubious, although well intended. Intermatic makes a
digital timer which uses a small relay to actually switch the light. The
package says it's OK to use with compact fluorescent bulbs, but I had 3 of
these timers go bad on me. The company said the relay was just too small for
don't recall this part blah blah blah, and they wouldn't have it modified
and ready for sale until next year. They ended up sending me a different
model whose final switching stage is non-mechanical, and I'm back to using
an incandescent bulb for my porch. If I had the time, I'd run a line to the
cellar and install the old-style timer - the kind in the grey metal box with
a wheel inside.

Anyway, you have to check the instructions that come with a timer, and even
then, it still may not work.