You can get halogen headlamps in a couple of flavors. There are the
generic issue models made by GE, etc. sold at Target, etc. Then there
are the expensive european models such as Hella, Cibie, etc. The
european headlamps have a removable bulb and they are often called
"quartz halogen" because the glass in the bulb is made out of quartz
to withstand the high heat. There is no comparison between the two
types of headlamps, the european ones put out much more light.
However, they are expensive, most of them are not DOT legal and they
pull a lot of current. The makers of these lamps recommend you install
a relay between the lamps and your headlamp switch to handle this
current. Most people don't and sometimes fry their headlamp switch.
If my memory serves me correctly the european headlamps came in 60 and
100 watt flavors. At 12 volts that would be 5 and 8 1/3 amps per
headlamp. Times 2 that would make either 10 or 16 2/3 amps for both.
This seems like quite a bit of current for the small switches in our
dashboards. Something to think about anyway. I am not sure of the
current draw of the generic halogen headlamps sold at Target, etc. but
I do not think it is much more than that of the original headlamps.
The bulb designation for these European lights is H1, H2, H3, H4. The
number describes the type of bulb it is, and therefore what socket
it will fit in. H1 is used in dedicated high beam headlamps, like
used in the 4 lamp headlamp systems found in American cars in the '60's.
H2 and H3 are used in fog and driving lamps. H4 is used in headlamps
that have both high and low beams. You will find that there are H4
bulbs that are rated "55/60" and "90/100". That is the "output" of the
bulb in low/high beam. Most of the "contoured" headlamps in todays
American and Japanese cars also use H4 bulbs.