On Wed, 14 Feb 2007 12:50:18 -0800, "Bob F"
wrote:


"Doug Miller" wrote in message
t...
In article W6HAh.3741$Aa5.925@trnddc01, "Pop`"
wrote:
w_tom wrote:
Light bulbs work at may voltages. For example, a 120 volt
incandescant bulb will work at 60 volts AND last for maybe 100 years
continuous. As voltage drops, bulb life expectancy increases
exponentially (about a factor of 12). As voltage drops, bulb
intensity also decreases exponentially. Sure, the 12 volt bulb will
work at 6 volts. But its light output will be massively diminished
and its efficiency is decreases (less light per amp of electricity).

So yes, a 12 volt lamp will work on 6 volts (if power supply can
provide sufficient current). Just not work very well.

NO, it will not. There will be insufficient heat in the element to
provide
any light or even a glow with a 12V bulb at 6V DC. A 12VDC bulb will
begin
to dim substantially at 9 VDC and may not even be visible in the light of
a
room.

I guess you didn't understand the part where he said "if power supply can
provide sufficient current."


If the voltage is insufficient, no power supply, no matter what current it
can deliver, will light the bulb.


However 6V probably IS sufficient to light a 12V bulb somewhat.
Measuring the voltage while it is actually connected to the bulb could
tell you something. It doesn't STAY at 6V no matter what.


Do not profess knowledge you do not have.

That's good advice, Poop. Maybe you should take it, too.

You say?

Bob

--
Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy