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?
Cheers, Rick
Not really. Although a 12volt bulb is unlikely to be damaged by having
6 volts across it, 6 volts will not get the filament hot enough to give much light. I'm assuming this is an incandescent bulb.To get advice on sources for your bulb, you'd need to say what kind of fitting it is, or, better, post a picture.
R.
At a very rough approximation, if you feed a 60w 12v bulb with 6v it will consume about 15 watts.
However, this is pretty crude because the filament will not get as hot as it's supposed to - and its resistance changes quite a lot with temperature - so God knows what you'll *actually* get.
In any case, the chances of getting much useful light out of it are slim because, at a lower temperature, most of the output will be in the form of infra-red rather than visible light.
Mail order?
No. 6 volts is only half the 'pressure' of 12 volts, so only half as much current flows. You'll only be putting a quarter of the power into the bulb.
Tell us more about these bulbs you can't get; perhaps post a picture, and what's written on them.
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.
Try a motor cycle dealer. You certainly *used* to get 'bikes with 6v electrics. a 12V bulb will do nothing useful.
Andy
What lamp base?
CPC have an H3 one:
Here's a picture of an H3 bulb (albeit not the one above)
These any good?
cheers, Pete.
As everyone else has said, "no", and "what type of cap?".
A pleasant enough firm to deal with, too.
Thanks all, I got them from a bike dealer last time but they were the wrong wattage and were a bit dim (i'll do the jokes).
I have some on order and will get the details from the bulb when they come in.
It is a bayonet type with one terminal on the base.
Cheers.
In message , Sparks writes
IIRC he's in Lancs - prolly not too far from Preston
In message , R D S writes
a 12v one might glow weakly ...
look on the RS or CPC website
One point not taken into account so far. A tungsten filament has a +ve temp coefficient and the resistance will be far too low if it is on a lower than design supply. This makes it difficult to estimate how a
12v bulb will work on 6v.
John, it's really of bugger all consequence
As I wrote above ...
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.