GB431630A - Improvements in or relating to the utilization of a gaseous conductor or discharge tube for controlling the operation of an electromagnetic device - Google Patents

Abstract

431,630. Automatic exchange systems. STANDARD TELEPHONES & CABLES, Ltd., 63, Aldwych, London.-(Assignees of Anderson, L. T. ; 96, North 18th Street, East Orange, New Jersey, and Low, F. K.; 179, Columbia Heights, Brooklyn, New York, both in U.S.A.) Feb. 8, 1935, No. 4104. Convention date, Sept. 7, 1934. [Class 40 (iv)] [See also Group XL] An impulse receiving circuit comprises a gas discharge tube, a two-winding relay in the anode-cathode path and a condenser connected between the cathode and the relay so that for one condition of the impulsing circuit (make or break), the tube intermittently ionizes and de-ionizes, and the condenser charges and discharges through the relay windings in such a manner as to hold the relay operated. The circuit may be applied to the direct setting of selectors in automatic telephony, to setting register-controllers or for impulse repetition. As shown, the grid of the tube 104 is connected to the negative leg of a calling loop ; the cathode is a few volts less negative than the exchange battery voltage as determined by a potentiometer 106, 107 including the heater of the tube, anode potential being provided by the exchange battery. The junction of the two windings L, H of relay 110 is connected by condenser 111 to the cathode. Normally the grid potential is sufficiently negative to block the tube, but when the calling loop is completed, the negative bias decreases and condenser 111 discharges over the low resistance winding L and the tube to operate the relay 110. As the condenser discharges, the anode potential falls until the tube ceases to conduct and the condenser charges again over the high resistance winding H which holds the relay. The relay may have a short-circuited third winding, or other device to make it slow.