Gate circuit

942,272. Gating circuits. WESTERN ELECTRIC CO. Inc. Dec. 14, 1960 [Dec. 21, 1959], No. 43013/60. Heading H3B. [Also in Division H1] In a gating circuit comprising gates a, b . . . n, Fig. 1, each having an input transformer T A , and an output transformer T c , there is provided a control circuit 13 for saturating any desired output transformer Tc, and the circuit is such that an input signal applied from a source 1 to a selected gate is gated to an output circuit 11 through the output transformers T c of all gates except the selected gate. Preferably, each gate has a third transformer T B also saturable by the control circuit 13. " OFF " condition.-In the " OFF " condition of a gate, say gate a, windings 9a, 10a are not energized. Input information from source 1 applied to windings 6a, 7a induces E.M.Fs. in windings 3a, 4a arranged so that the E.M.Fs. substantially cancel. Any current Ia in windings 3a, 4a resulting from unbalance of transformers T A , T B flows through the windings 3a, 4a, 5a of gate a and divides and travels down similar windings of the other gates b . . . n. The component currents 16 ... In induce E.M.Fs. in output windings 86 ... Sn of transformers T c . The total current flow in windings 8b . . . 8n is of equal magnitude but of opposite direction to that flowing in output winding 8a and thus no resultant current flows in output circuit 11. " ON " condition,-In the " ON " condition of a gate, say gate a, windings 9a, 10a are energized by a pulse from control circuit 13 to saturate transformers T B , T c . Information from source 1 applied to windings 6a, 7a induces an E.M.F. at winding 3a, 4a, 5a, and the current divides and travels down similar windings of the remaining gates b . . . n. The currents Ib . . . In induce E.M.Fs. in the output windings 8b. . . 8n but since transformer T c of gate a is saturated no E.M.F. is induced in winding 8a. The currents flowing in output windings 8b . . . 8n appear at output circuit 11. Alternative arrangements.-When a saturating pulse is applied to windings 9, 10, Fig. 4, an undesirable E.M.F. may be induced in winding 8 prior to saturation of transformers T B , T c and this may be reduced by a fourth transformer T D arranged such that, when windings 9, 10, 52 are energized, the E.M.Fs. induced in output windings 8, 51 produce equal and opposite current flow. One fourth transformer may be common to all the gates by using a common core on which are wound an output winding and control winding for ea