A useful circuit for dielectric constant, power factor, and conductivity measurements at high frequencies
P A Cooper · Journal of Scientific Instruments · 1925
The standard method of measuring power factor at radio frequencies is described and its limitations discussed. In the new circuit greater sensitivity and quickness of manipulation are obtained by using valve rectification, instead of a heating effect, to indicate resonance between tuned circuits. The working circuit, which is often of high decrement, forms an integral part of the oscillator and the sharpness of tuning is then determined mainly by the wavemeter circuit which may have quite a low decrement since a wavemeter detector is not required. Expressions are developed which can be applied to the measurement of power factor, dielectric constant, and conductivity.