On 12/11/2009 01:24 PM, Lew Hodgett wrote:

For a given wattage of lamp, the total lamp resistance of the lamp
increases in direct proportion to the rated voltage.

I don't think this is correct.

Power = V^2/R

Based on that, to keep wattage constant resistance must increase as the
square of the voltage. Double the voltage and the resistance has to
increase by a factor of four.

Chris