GB661410A - Improvements in and relating to current pulse generating circuit arrangements - Google Patents

Abstract

661,410. Condenser arrangements. MINISTER OF SUPPLY. Jan. 16, 1950 [Jan. 31, 1949]. No. 2675/49. Class 38 (iv). [Also in Group XL (c)] A high voltage pulse generator comprises a capacitor which is charged from a power source and discharged into an inductive load by means of an ionizable switching path, a first rectifier being connected in parallel with the switch and a second rectifier connected in series with the load and an auxiliary inductor connected in parallel with the series circuit of the second rectifier and load, the time constant of the circuit formed by the auxiliary inductor, the capacitor and the second rectifier being long compared with the de-ionization time of the switch. The Figure shows a capacitor C2 which is charged from the D.C. source of voltage V via the resistor R and is periodically discharged into the inductive load L1 and the auxiliary inductor L2 when the ignitron V1 is fired. The pulse of current which flows during the discharge is approximately a half sinusoid and has a duration t determined by the resonant frequency of capacitor C2 and the inductance of the load L1. At the end of time t the voltage across capacitor C2 has reversed but reversal of current through the load L1 is prevented by rectifier D1. Rectifier D2 presents a low resistance path for reverse current flow and thus effectively shorts ignitron V1 when the direction of current flow through capacitor C2 reverses. At the end of interval t therefore current flows through the circuit D2, C2, L2 for a time T which is determined by the resonant frequency of C2 and L2 and which may be made approximately equal to the interval between successive current pulses. The impulse voltage across the ignitron VI can be made such that a voltage which would otherwise result in back-firing is not reached within its de-ionization time.