Ohmmeter with power-source-isolating transducers for testing hazardous or sensitive circuits

Claim 1

AN ELECTRICAL IMPEDANCE MEASURING DEVICE, COMPRISING, ALTERNATING CURRENT GENERATING MEANS INCLUDING A MULTI-VIBRATOR, A PAIR OF TRANSDUCERS CONNECTED TO SAID MULTI-VIBRATOR, EACH OF SAID TRANSDUCERS BEING ALTERNATELY ENERGIZED THEREBY, A SECOND PAIR OF TRANSDUCERS POSITIONED IN SPACED RELATIONSHIP TO SAID FIRST PAIR AND IN ELECTRICAL ISOLATION THEREFROM, SAID SECOND PAIR OF TRANSDUCERS BEING RESPONSIVE ONLY TO SAID FIRST PAIR OF TRANSDUCERS, A TRANSFORMER HAVING A PRIMARY AND A SECONDARY WINDING, SAID SECOND PAIR OF TRANSDUCERS BEING COUPLED TO SAID PRIMARY WINDING AND INDUCING AN ALTERNATING CURRENT TO FLOW THEREIN, SAID ALTERNATING CURRENT INDUCING AN OUTPUT IN SAID SECONDARY WINDING, VOLTAGE DROP INDICATING MEANS COUPLED TO SAID PRIMARY WINDING, AND TEST LEADS COUPLED TO SAID SECONDARY WINDING WHEREBY ELECTRICAL IMPEDANCE MEASURING MEANS IS PROVIDED WHEREIN SAID OUTPUT IS OF SUCH LOW LEVEL AS TO PERMIT THE CHECKING OF HAZARDOUS OR SENSITIVE CIRCUITS WITHOUT DETONATION OR INJURY THEREOF, AND WHEREBY AN IMPEDANCE LOAD CONNECTED ACROSS SAID TEST LEADS CAUSES A CHANGE IN LOADING ACROSS SAID SECONDARY WINDING WHICH IS REFLECTED BACK INTO SAID PRIMARY WINDING AND INDICATED ON SAID VOLTMETER AS A CHANGE IN VOLTAGE DROP THEREACROSS, SAID VOLTMETER BEING CALIBRATED IN OHMS TO PROVIDE A VALUE OF THE IMPEDANCE LOAD ACROSS SAID TEST LOADS.