"Roger Mills" wrote in message
...

"Andrew Gabriel" wrote in message
...

I described this effect in more detail in article:


http://groups.google.com/groups?selm...net.uk.sun.com

--
Andrew Gabriel

Could you re-check the above link URL please - I can't make it work!

Roger



Hi Andrew,

Having now read your article which you kindly emailed to me, I think that we
are more or less in violent agreement!

We are both saying that - by and large - low voltage lamps are more
efficient than high voltage lamps with the same power consumption because
they run at a higher temperature - which is possible, or even inherent, as a
result of the different filament profile.

You explain *why* they run hotter - which I didn't in my previous post, but
you don't really explain why hotter means more efficient - which I did in
terms of the colour temperature and wavelength of the emitted radiation.

I accept that there are limits as to how low you can go in voltage because
of other factors like the resistance of the filament carriers etc. I would
be interested in your view concerning the optimun voltage for a 50w - or
even 35w - as opposed to 100w lamp. [We have LV 50w lamps in one room and
35w lamps in another - and I'm not sure there's all that much difference in
the light output!]

Roger