Gib Bogle wrote:
On 29/10/2010 8:46 p.m., Tabby wrote:
On Oct 29, 6:17 am, Gib wrote:
On 29/10/2010 2:12 p.m., Tabby wrote:

What's the diameter of the thread on the bulbs concerned? 7.5w
suggests candelabra base (12mm) lamps, often used to illuminate the
translucent base of table lamps in the US. Give us an idea of the
overall shape and dimensions and the base dimensions. If my guess is
right, then if you've any problems ordering from the USA, an E11 base
with a 230 volt 15 watt rating will probably fit OK and be available
here and give the same sort of illumination level. Also last forever
at that sort of downrating.

It would be way too dim.

Right, he wants 230v 30w.

Any 230/240v filament bulb on 110v would be way way down on efficacy,
and be no use.

I'm assuming that the filament resistance is constant, in which case the
power draw for a 230v 30w bulb on 120v would be about 7.5w. Am I
missing something?


yes. Thermal coefficient of resistivity.

Current will in fact be a lot higher.