[VAC] Re: More on lamps

["Dr. Gerald N. Johnson, electrical engineer" <geraldj@xxxxxxxx>]

A lamp industry rule of thumb about tungsten filament lamp life versus
voltage:

A 5% reduction in voltage will result in a 10% reduction in light output
and a doubling of lamp life. Conversely, a 5% increase in voltage will
result in a 10% increase in light output and will cut the lamp life in
half.

Incidentally, SAE lamp life tests include shock and vibration.

Gerald J.