GB789348A - Improvements in or relating to apparatus for producing electrical impulses - Google Patents

Abstract

789,348. Spark gaps. MICAFIL, Ltd. Jan. 24, 1956 [Jan. 25, 1955], No. 2292/56. Class 39(1). [Also in Group XL(c)] A pulse generator comprising a spark gap is controlled by insulating one of the spark gap electrodes on the low potential side from earth and deriving an oscillatory voltage from the generator which controls the potential of this electrode so that the spark gap flashes over during the steep front of the first transition of the control voltage through zero. The figure shows a pulse generator SG comprising a number of auxiliary spark gaps and a main discharging spark gap SF, the low voltage electrode of which is connected to earth through an auxiliary pulse generator comprising a tuned circuit LCR across which an auxiliary spark gap HF is connected. When the main pulse generator generates a pulse of voltage the tuned circuit LCR is shock excited to generate a damped oscillation the circuit constants being arranged so that when the voltage passes through zero level the spark gap SF has a voltage across it sufficient to cause it to fire and a high voltage pulse is generated across the output terminals. The position of the firing may be regulated by altering the values of either L or C. The sparking points of the main gap SF are preferably provided with a radio active substance on both spheres near the vicinity of the ignition point. Fig. 3 shows the construction of the control pulse generator the coupling capacitor being located inside an insulating tube 1 which is mounted on metal stand 2, the fitting 4, which is connected to the insulating sphere of the spark gap on the earth side, also supports the auxiliary gap 5 and a parallel interchangeable inductance 6. The natural frequency of the oscillating circuit can be regulated by means of taps on the coupling capacitor inside tube 1 or by changing the inductance 6.