Reverse current indicating circuit

Claim 1

IN A SYSTEM FOR MONITORING THE AMPLITUDE OF DIRECT CURRENT FLOWING IN A LINE OF THE TYPE IN WHICH THE SENSING ELEMENT COUPLED TO SAID LINE IS A SATURABLE REACTOR HAVING ONE OR MORE CORES WHEREIN EACH CORE HAS A WINDING, AND INCLUDING A SOURCE OF EXCITATION APPLIED TO SAID SATURABLE REACTOR TO DERIVE AN OUTPUT THEREFROM THAT IS INDICATIVE OF THE CHARACTERISTICS OF SAID DIRECT CURRENT, A CIRCUIT FOR INDICATING THE DIRECTION OF CURRENT FLOW COMPRISING A GATE CIRCUIT, MEANS COUPLED TO SAID SOURCE OF EXCITATION FOR DERIVING SAMPLING PULSES AS A FIRST INPUT TO SAID GATE CIRCUIT, MEANS COUPLING THE VOLTAGE ACROSS ONE WINDING OF SAID SATURABLE REACTOR TO SAID GATE CIRCUIT AS A SECOND INPUT, SAID GATE CIRCUIT INCLUDING MEANS FOR ESTABLISHING A THRESHOLD VOLTAGE FOR SAID SECOND INPUT SO THAT AN OUTPUT INDICATION OF THE DIRECTION OF CURRENT FLOW IS OBTAINED FROM SAID GATE CIRCUIT WHEN A SAMPLING PULSE IS AT SAID FIRST INPUT AND THE VOLTAGE AT SAID SECOND INPUT EXCEEDS SAID THRESHOLD VOLTAGE.