Electromagnetic balance

Claim 1

IN AN ELECTRIC BALANCE HAVING A PIVOTED BEAM, A PAN FOR THE RECEPTION OF THE SUBSTANCE TO BE WEIGHED CONNECTED TO SAID BEAM, A MAGNETIC COUNTERBALANCING DEVICE ASSOCIATED WITH SAID BEAM AND HAVING A CORE PROVIDED WITH AN AIR-GAP, A COIL DISPOSED IN SAID AIR-GAP, SAID COIL AND CORE BEING RELATIVELY MOVABLE, ONE THEREOF BEING FIXED AND THE OTHER BEING MOVABLE WITH SAID BEAM, SAID COUNTERBALANCING DEVICE EXERTING A COUNTERBALANCING FORCE ON SAID BEAM, A SENSING DEVICE COMPRISING A CORE HAVING AN AIR-GAP AND A COIL IN SAID AIR-GAP, ONE THEREOF BEING FIXED AND THE OTHER MOVABLE WITH SAID BEAM, POWER SUPPLY MEANS INCLUDING TWO SOURCES OF DIRECT CURRENT, A COMMON CONDUCTOR CONNECTING THE POSITIVE SIDE OF ONE SOURCE TO THE NEGATIVE SIDE OF THE OTHER SOURCE, AN ELECTRONIC OSCILLATOR HAVING A TUNED RESONANT INPUT CIRCUIT CONNECTED TO SAID POWER SUPPLY MEANS AND AN OUTPUT CIRCUIT, SAID INPUT CIRCUIT INCLUDING THE COIL OF SAID ACTUATING DEVICE, THE COMBINATION OF (A) AN ELECTRONIC COUNTERBALANCING SYSTEM INCLUDING (B) A COMMON CIRCUIT CONNECTED TO THE COMMON CONDUCTOR OF SAID POWER SUPPLY MEANS, (K) BRANCH CIRCUITS CONNECTED TO THE OTHER TERMINALS OF SAID SOURCES OF DIRECT CURRENT, (E) AN NPN TRANSISTOR AND A PNP TRANSISTOR, SAID TRANSISTORS HAVING INPUT AND OUTPUT ELEMENTS, (F) THE OUTPUT ELEMENTS OF SAID NPN TRANSISTOR BEING CONNECTED IN SAID BRANCH CIRCUITS, (H) THE COIL OF SAID COUNTERBALANCING DEVICE BEING ENERGIZED BY THE CURRENT FLOWING IN SAID COMMON CIRCUIT, (I) WEIGHT INDICATING MEANS ENERGIZED BY THE CURRENT FLOWING IN SAID COMMON CIRCUIT, (J) AND MEANS FOR RECTIFYING THE OUTPUT FROM SAID OSCILLATOR AND CONNECTED TO THE INPUT ELEMENTS OF SAID TRANSISTORS.