At 06:25 PM 7/17/2010 Saturday, Richard Jones wrote:
>Years ago I put a little cube module in the ceiling of my old 911
>that does that.  I assume it has a capacitor in it that just
>stores some juice to keep the light on and as it runs out
>the light dims out.

Hi Richard -- You have no idea what an absolutely enormous capacitor
it would take to do that.  Just as a very rough guess (within two
orders of magnitude, say) it would fill your front seat.  No doubt a
capacitor is involved, but it will be used for timing, not energy storage.

:)
d