No difference. You can use 'em on DC.

I recently bought a couple of 12V Halogen gooseneck clip-on lamps at my
local supermarket, ditched the "transformer brick" that steps down
household AC to 12VAC, and attached 12V cigarette lighter plugs. They clip
on nicely along the kitchen shelf, or to the edges of the tables.

At 10:06 PM 9/27/2004 -0400, Mike Collum wrote:
>I have some "Under counter" halogen lighting fixtures that are fed through a
>transformer that steps down to 12 volts.  Can these be connected directly to
>12 volt DC for use in the Westy or must I use halogens that are designed for
>DC operation?
>
>Thanks,
>
>Mike