GB660490A - Improvements in or relating to phase-shift circuits for grid-controlled gas discharge tubes - Google Patents

Abstract

660,490. Phase shifting. MULLARD RADIO VALVE CO., Ltd., and LUCAS, J. H. May 20, 1949,No. 13532/49. Class 38 (ii). A phase shifting circuit for the grid control of a pair of discharge tubes 13, 13<SP>1</SP> operating in phase opposition from a single-phase supply 3 has a transformer 1 having a single-phase primary winding 2, a first secondary winding 14 supplying phase-opposed voltages to the anodes of the discharge tubes, a second secondary winding 4 providing phase-opposed voltages and a pair of saturable reactors 7, 7<SP>1</SP> connected each in series with a resistor 8, 8<SP>1</SP> to form a closed four - element network having two opposite junctions connected across the second secondary winding 4 and the other two opposite junctions 9, 9<SP>1</SP> connected to supply grid potentials to the pair of discharge tubes, the pair of saturable reactors having direct current windings 10, 10<SP>1</SP> connected in series with each other across a variable direct current supply 11. The inductance 12 is provided to prevent an alternating potential from appearing across the direct current supply and, since the windings 10, 101 are so connected that the alternating potential in them largely cancels out, the inductance 12 may be smaller than is the normal practice. If the direct current supply has a very high internal impedance the inductance 12 may be omitted. The waveform of the voltages appearing at the grids of the discharge tubes exhibit very rapid changes, thus ensuring very precise control of these tubes. The arrangement may be used on a multi-phase supply if more than one pair of tubes are required.