GB654394A - Improvements in methods of and means for comparing or measuring the constants of electric circuit elements - Google Patents

Abstract

654,394. Inductance, capacitance and Q-value measuring. MERCIER, M. A. Dec. 30, 1947, No. 34780. Convention date, Jan. 9, 1942. [Class 37] A variable oscillator feeds a tuned circuit which includes the element to be measured, the output being applied to a detector adapted to indicate the maximum value of output, the tuned circuit comprising a fixed component, an adjusting component and a vernier adjusting component. A. variable oscillator 0 modulated by a tone frequency from H supplies a circuit formed by an unknown inductance Lx in parallel with a condenser C, a variable condenser C1 and a vernier condenser C2, and the oscillator is varied until it supplies oscillations of the frequency to which the circuit Lx, C, C1 and C2 is resonant, as shown by maximum response at T or E; the value of the inductance is then read from the dial of the oscillator M. To measure variations of further inductances, they are each inserted in place of Lx and the oscillator M maintained constant while C2 is varied to produce maximum response, C2 being calibrated to indicate percentage variation. The inductance may be replaced by an unknown condenser, and the condensers by suitable inductances, Fig. 2, not shown. The circuits for measuring inductance or capacity may be connected at will to the oscillators and detector circuits, Fig. 3, not shown. If the power of the oscillator is maintained constant, inductances and capacities of similar value may be tested for their quality, i.e. their resistance, by comparison of the value of the maxima indicated at T or E. The oscillator M preferably has a series of adjacent ranges, Fig. 4, not shown.