[thechat] Global lightbulbs

[Tony Crockford]

> What would happen if you took a light bulb from North America
> and screwed it
> into a British fixture and turned it on?

seriously?

Britain has a 240v electricity supply US has a 110v supply.

If you could actually screw it in (and I guess if you had an edison
screw type fitting instead of the more usual UK bayonet type you could)
then some simple maths will tell us.

Power = Current x Voltage (approximate in AC situation)

Current= Power/voltage

Resistance = Voltage/Current

All these are approx figures because we're dealing with alternating
current so a 100w US bulb has a resistance of: 122 ohm a 100w UK bulb
has a resistance of 600 ohm

so a 100w US bulb plugged into a 240v supply would draw 1.96 amps, not
enough to blow the fuse, but enough to make the bulb shine with 470w of
power.


So your US bulb would glow about 4 times as brightly, in a UK holder and
would probably get very hot before burning out.

it might explode too, so stand well back!


If my calculations are wrong then I'm sure some one will tell us!

hth

Tony