GB697879A - Improvements relating to electric peak voltage measuring circuits - Google Patents

Abstract

697,879. Voltage measurements. METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. June 17, 1952 [June 18, 1951], No. 14448/51. Class 37. A circuit for measuring the peak value of a varying voltage includes a cathode follower valve, the cathode of which is connected through a rectifier to a peak voltage condenser, together with means for measuring the voltage across the condenser and means for discharging the condenser. A transient voltage, the peak value of which is to be measured, is applied to the grid of a cathode follower valve VI, Fig. 2, the cathode circuit of which includes a condenser C1 in parallel with a resistance R1. The peak values of the voltage across the condenser C1 are applied through a diode V2 to charge a peak voltage condenser C2 to the same voltage, so that when the condenser Cl discharges through the resistance R1 the condenser C2 remains charged to the peak voltage until a short-circuiting switch S is closed. The peak value is measured by an instrument M in the cathode circuit of a valve V3. In a modification, Fig. 3, suitable for measuring recurring voltages, the switch S is replaced by a valve V4 which is normally non-conducting. Positivegoing pulses applied to its grid cause it to conduct and partially discharge the condenser C2. In a modification, Fig. 4, the cathode circuit of the valve V3 includes a condenser C3 in parallel with the cathode resistance R2. Peak voltages generated across the condenser C3 are passed through a second diode V5 to charge a second peak voltage condenser C4 which is partially discharged when pulses are applied to the grid of a valve V6. The voltage across the condenser C4t is applied to the grid of a valve V7, in the cathode circuit of which is the measuring instrument M. The discharge circuits for the two peak voltage condensers C2, C4 are made conductive alternately so that the output voltage remains steady except when the peak voltage varies in amplitude.