GB655295A - Improvements in or relating to high frequency electron discharge tube circuit arrangements - Google Patents

Abstract

655,295. Valve amplifying circuits. RADIO CORPORATION OF AMERICA. Oct. 14, 1946, No. 5642/50. Convention date, Oct. 16, 1945. Divided out of 655,247. [Class 40 (vi)] [Also in Groups XL (a), and XL (b)] A grounded grid amplifier comprises a valve having a coaxial line resonator connected to the anode and having a bifilar cathode, the-leads to which are surrounded by a metal tube which is connected to the leads at the far end and to which the input is applied. As shown, highpower amplifier for a frequency-modulated transmitter uses two similar grounded grid stages fed from a driver stage of the type described in Specification 655,247, through an input-coupling circuit 120 -and supplying an aerial through an output Biter 126. The grid 132 which is capacitively grounded around the periphery of its connecting disc (not shown) encloses a bifilar cathode 134 shielding it from a closed-off cylindrical anode 130. The cathode leads are connected by capacitors 139, 141 to the centre point of the cathode and pass through a metal cylinder 140 to the filament transformer where they are byepassed to the end of the tube and earthed. The cylinder is tuned by a capacitor 150 so that the effective length to the top of the cathode is ¥ #. The anode is connected to a surrounding metal cylinder 154 which with an earthed cylinder 156 forms the anode timed circuit. These two cylinders are connected at the “ # point by a capacitor comprising two insulating discs whose upper metallized surfaces are interconnected by bolts 174 and are in electrical contact with the outside cylinder through fingers 180 and whose lower metallized surfaces are inter-connected by bolts 182 and are in electrical contact with the inner cylinder through fingers 184.