Microwave Apparatus

Abstract

Abstract 1,156,893. Protective systems. VARIAN ASSOCIATES. 16 Jan., 1968 [16 Jan., 1967; 24 Nov., 1967], No. 2382/68. Heading H2K. [Also in Divisions H3 and G3] A microwave oscillator (see Division H3) comprises an amplifier, e.g. klystron 2 with a feedback path feeding power amplified by the amplifier to the input, to sustain oscillation and including an attenuator 5b, e.g. a PIN diode. An arc protector is incorporated for sensing an arc in the output waveguide, comprising a photo-cell 10 disposed in the waveguide, any output from which is fed via an amplifier to control attenuator 5b so as to reduce the power level of the oscillator until the arc is extinguished. Alternatively (Fig. 6, not shown), the photo-cell output is fed via an amplifier to the gate of a S.C.R. connected in series between a power supply and the variable attenuator, so as to cause the former to deliver a voltage to the attenuator reducing the attenuator loop gain below unity, stopping oscillation. When the arc is extinguished the S.C.R. is returned to its "off" state by opening a switch in the power supply lead, thereby removing the drive to the attenuator and allowing normal operation to be resumed.

Inventors

• 👤 Norman Harwood Williams

Bibliographic Details