GB451618A - Improvements in or relating to apparatus responsive to the phase difference between two voltages - Google Patents

Abstract

451,618. Automatic control systems. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London. March 23, 1935, No. 9137. Convention date, March 23, 1934. [Class 38 (iv)] [See also Groups XL and XXXVI] Oscillation frequency; power factor.- In a device responsive to the phase angle between two voltages, one voltage E<1> controls the intensity of a stream 22 of electrified particles in an electric discharge device 13, the other voltage E<2> deflects the stream and plates 20, 21 with overlapping and longitudinally spaced edges as shown intercept the stream on either side of its mean path so that the voltage V<1> between the plates 20, 21 varies with the phase angle between the voltages E\ E<2>. As shown, the stream 22 is a cathode ray passing a focusing electrode 16 and an anode 15 in the form of a coating on the wall of the tube 13 and the ray may be sharply focused or broad or in the form of a flat sheet. The voltage E<1> is applied to the grid 17 and the voltage E<2> to deflecting plates 24, 25. The plates 20, 21 are connected together through a resistance 27 which may be such that the potentials of the plates are time integrals of the ray currents to the plates or such that these charges on the plates leak off rapidly. The overlapping edges of the plates produce the effect of zero transverse displacement so that the ray never passes between the plates. To eliminate errors due to external fields, two tubes 13 may be connected in parallel with opposite deflecting and collector plates connected together, Fig. 4 (not shown). A radio-frequency valve-oscillator is synchronized with a principal oscillator by deriving the voltages E<1>, E<2> from the two oscillators and using the voltage V<1> to control the valve-oscillator as by varying the bias on its grid, Fig. 5 (not shown), and the connections may be such that the voltages E<1>, E<2> are in quadrature, and the voltage V<1> zero, when the oscillators are in phase. A regenerative receiver is kept at maximum regeneration without oscillating by keeping the power-factor of the grid circuit small but not zero, Fig. 6 (not shown), the voltages E<1>, E2 being derived from the voltage and current in the inductance in the grid circuit and the voltage V<1> controlling the degree of coupling of the grid and anode circuits as by varying the grid bias.