Current Steering in Magnetic Circuits

Magnetic switches are described in which the current from an energizing source is guided or steered through one out of many possible parallel branches, the conducting branch being selected by the presetting of appropriate magnetic elements. Only a few tubes are required for energization, and the outputs, obtained with reasonable efficiency, are substantially independent of exact circuit parameters. Current steering is achieved either by core-diode combinations or by transfluxors. Decoding switches, of both types, for the selection of one out-of-many outputs according to an input code are described in detail. A current of precise amplitude of the order of amperes is switched to a selected path in microseconds. Steered decoders are ideal for addressing core memories. A commutator switch for delivering sequentially a given current to a number of loads is described. Current steering makes possible simple magnetic counters and universal code converters. Experimental results of laboratory models of decoders and commutators are given. The principle of current steering broadens greatly the usefulness of magnetic switches by providing economy of associated electronic drivers and accuracy of switched currents.