Re: Bending of Ohm's Law was Re: Gap Question

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br> 

Tesla list wrote:

(several comments about how to make constant-temperature measurements
of the v x i characteristic of of a lamp)

It's easy to keep the temperature constant by measuring what happens
with high-frequency AC. Put a small resistor in series with the lamp,
and connect the combination to a low-impedance signal generator
(use an amplifier if necessary). Measure then in an oscilloscope the
voltage over the combination x the voltage over the small resistor,
with the oscilloscope in XY mode. With high enough frequency you see
a straight line, with an inclination that depends on the signal
amplitude, or in the average power dissipated in the lamp.

A simple way to measure the characteristic, with the temperature
effect appearing: Get a 12 V lamp and 8 1.5 V batteries.
Measure then the current with 1, 2, 3, ..., 8 batteries in series
and plot a i x v graph.

Antonio Carlos M. de Queiroz