> If two 120V bulbs in series works well, then why don't the manufacturers
put
> two 120V filaments in series in one envelope?
>
> Or just create one filament, with the same wire, but twice as long?

First, I said this mostly to point out the absurdity of the situation.  But
to answer your question, you would end up with a bulb that is twice the
wattage.  That's fine if you want that much light in one place.  In other
words, a 200W 240V bulb should be able to last as long as a 100W 120V bulb.
But, if you want 100W of light, then a 100W 120V bulb is going to last
longer than a 100W 240V bulb.  If you are lighting an area with multiple
bulbs already, then using 120V bulbs wired in series in pairs should, in
theory, increase life.  In practise???

Personally, I use compact flourescents except where the bulb is turned on
and off frequently or is only on rarely.  Despite their higher purchase
price, compact flourscents are cheaper in the end because they use less
electricity.


********************************************************************
Olin Lathrop, embedded systems consultant in Littleton Massachusetts
(978) 742-9014, olin@embedinc.com, http://www.embedinc.com

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