A guarded circuit for the measurement of dielectric properties at radio frequencies
J. W. Dziminanski, R. K. Witt, J. J. Chapman · 1948
The present method employs the very commonplace phenomenon of timing a parallel combination of inductance and capacitance to resonance. In Fig. 1 a constant voltage E is applied to the L C tuning circuit and C is varied until the current I is a minimum. This residual current is a measure of the total loss of the tank circuit. This loss may be indicated by a figure in mhos conductance, that is the quotient of I/E. When a specimen Cxis placed across condenser C and the circuit retuned a greater residual current results. The change in the setting of C is a measure of the specimen capacitance and the increase in mhos conductance is a measure of the specimen loss.