GB948020A - Improvements relating to protective apparatus for pulse electrical discharge devices - Google Patents

Abstract

948,020. Pulse generating circuits. ASSOCIATED ELECTRICAL INDUSTRIES Ltd. Oct. 23, 1962 [Oct. 24, 1961], No. 38069/61. Heading H3P. In a protective arrangement for a pulse generator, pulses representing the current and voltage of the main output are applied to an electronic comparator which is arranged to give an output in the event of a variation from the normal relative values of current and voltage. Fig. 3 shows a pulse generator in which a pulse forming network PFN is charged via inductor 1 and diode D1 and discharged into a load under control of a thyratron S triggered by pulses from a source T. Pulses representing the waveforms of current and voltage in the load are respectively provided by a current transformer and capacitive divider and fed to a comparator C which provides an output only if the voltage/ current ratio is incorrect, e.g. due to flashover in the load. The output from comparator C opens a gate G which cuts off the trigger pulses to the thyratron S or reduces the excitation voltage. Fig. 2 shows a suitable comparator comprising valves V1, V2 arranged as a differential amplifier. The current and voltage pulses are fed in via terminals A, B and capacitive dividers C1 . . . C4. Capacitor C2 is adjusted so that the output is zero under normal conditions. The output of the circuit shown in Fig. 2 may be fed to a counting circuit which provides an inhibiting pulse only after a predetermined number of flashovers. The load in Fig. 3 may consist of a klystron, magnetron or valve oscillator.