Existential Angst wrote:

"Rich Grise" wrote in message
...
Michael A. Terrell wrote:
Josepi wrote:

Yes, having two light bulbs with one as a standard could help your
estimation of brilliance providing you knew the "standard" one was being
powered by exactly the rated voltage. Since power is proportional to the
square of the applied voltage the power and therefore the brilliance
could be somewhat off for the purposes of good measurement.

Lightbulbs are not a linear load. Their resistance goes up as the
voltage increases. You would need to monitor the voltage and the current
to get anything useful.

Just a nitpick, but technically, the resistance goes up as the
_temperature_
increases. :-)

Does anyone know what this curve looks like? I would actually like a V vs.
I curve for a typical incandescant.
Googled some, wiki has an inneresting table on incandescant efficiency
http://en.wikipedia.org/wiki/Incandescent_light_bulb

but I haven't found an actual V vs I graph. I spose I could just take a
bulb and jot down some numbers, using a variac, eh?

Presumably a similar curve would arise from both AC and DC?


That would give you the data for that one bulb. There are
manufacturing variations from lamp to lamp. For instance: HP used a
small lamp in their early audio generators to control the gain. They
had to be hand selected to get the lowest distortion in each generator.


--
You can't fix stupid. You can't even put a Band-Aid™ on it, because it's
Teflon coated.