In message , Richard Clark
writes
On Thu, 9 Dec 2010 19:21:48 -0800 (PST), JIMMIE
wrote:

I built a wattmeter of sorts around a circuit like that. After tuning
up the transmitter to light bulb dummy load I would measure the
resistnace of a photo resistor exposed to the light then see how much
60Hz AC voltage and current took to light the lamps to the same
brillance.

Hi Jimmie,

An excellent example of the concept of a transfer standard. This
method is one of the oldest and most robust methods of accurate
measurement. It removes a lot of variables (by, ironically, not
changing them) that would be exceedingly difficult to determine their
impact upon an accurate measurement.

Do a Google on "Grease Spot Photometer" (back to school physics, over 50
years ago!). Very simple to make, and pretty accurate.
--
Ian