In article ,
R D S wrote:
I use 6v bulbs, 15 Watt.

I struggle to get hold of them locally, could I use a 12v bulb? And if
so what wattage would be best?

My understanding of bulbs is that electricity passes through the
filament, it gets hot and glows, so there would surely be
interchangeability, is this about right?

To make an efficient bulb the filament has to glow at a specific
temperature - and this is achieved by the design of the filament. And the
resistance changes dramatically from cold to hot. Two lamps with the same
nominal resistance when hot will have very different filaments according
to the voltage.

--
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Dave Plowman London SW
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