Abstract: A current director and interface circuit to prevent damage to a transformer relay by the simultaneous activation of a plurality of bidirectional switches. A current director prevents current flow in the secondary winding of the transformer relay in a second direction above a predetermined switching threshold for a predetermined succeeding time period after current has flowed in the secondary winding of the transformer relay in a first direction above a predetermined inhibit threshold during a predetermined preceding time period.

Abstract: A control system adapted to control a plurality of transformer relays. An electrical isolation network is coupled to each of a plurality of transformer relays, having a pair of common control lines and providing electrical isolation for each of the plurality of transformer relays. A switch is coupled to the electrical isolation network and is coupled in parallel to the plurality of transformer relays providing selection of state of all of the plurality of transformer relays. The electrical isolation network may also provide control, as e.g. unidirectional current flow, for selecting a state of each of the plurality of transformer relays. In a preferred embodiment the electrical isolation network includes an array of diodes.

Abstract: A system adapted to remotely control a transformer relay. The load switch of a transformer relay is controlled by controlling the direction of current flow in the secondary winding. A switch module is coupled with two wires to the secondary winding of the transformer relay providing a unidirectional current flow above a predetermined threshold in the secondary winding in response to a control signal. The unidirectional current flow may be selectively controlled in either direction or may be only purely unidirectional. A control module is then coupled to the switch module momentarily producing the control signal in response to an external stimulus. The switch module, the control module, or both draw a quiescent current from the secondary winding of the transformer relay when the switch module is not activated. The quiescent current is of an amount which is less than the predetermined threshold.