Car Headlights

[Haynes David]

Sam L. Smith wrote :

> Question: On high-beam, do both the low-beam and high-beam filaments
> light simultaneously, or only the high-beam filament?

Here in the UK, all cars with combination headlights I have seen use high or
dip beam, not both at once. Most twin headlight cars (ie four lamp units)
light both on high beam. I would beware lighting both filaments in a 
combination
bulb due to excess heating of the lamp, especially if you like high wattage 
bulbs
such as 80W or 100W high beams.

Dave H.