D.-c. stabilizing amplifier

Claim 1

IN A D.-C. AMPLIFIER HAVING MEANS DEFINING A POSITIVE DIRECT VOLTAGE SUPPLY TERMINAL AND A NEGATIVE DIRECT VOLTAGE SUPPLY TERMINAL WITH RESPECT TO GROUND POTENTIAL, THE COMBINATION COMPRISING, A DIFFERENTIAL INPUT STAGE OF AMPLIFICATION INCLUDING A PAIR OF TRIODE SECTIONS EACH HAVING AN ANODE, GRID, AND A CATHODE, A FIRST PAIR OF RESISTORS CONNECTING SAID ANODES RESPECTIVELY TO THE POSITIVE SUPPLY TERMINAL, AN OUTPUT TERMINAL FOR SAID STAGE CONNECTED TO THE ANODE OF ONE OF SAID SECTIONS, A CIRCUIT FOR CONNECTING SAID CATHODES TO THE NEGATIVE SUPPLY TERMINAL, MEANS FOR APPLYING AN INPUT POTENTIAL VARIABLE THROUGH A PREDETERMINED POSITIVE AND NEGATIVE RANGE WITH RESPECT TO GROUND POTENTIAL TO THE GRID OF THE OTHER OF SAID SECTIONS, A SECOND PAIR OF RESISTORS CONNECTED IN SERIES CIRCUIT ACROSS THE POSITIVE AND NEGATIVE SUPPLY TERMINALS AND HAVING A COMMON JUNCTION, THE POTENTIAL OF WHICH IS RELATED TO THE VOLTAGE DIFFERENCE OF THE POSITIVE AND NEGATIVE SUPPLY TERMINALS, AND A VOLTAGE REDUCING CIRCUIT COMPRISING A THIRD PAIR OF RESISTORS CONNECTED IN SERIES BETWEEN SAID GRID OF SAID ONE SECTION AND GROUND AND A RESISTOR CONNECTING THE COMMON FUNCTION OF SAID THIRD PAIR WITH SAID COMMON JUNCTION OF SAID SECOND PAIR FOR APPLYING A POTENTIAL TO THE GRID OF SAID ONE SECTION PROPORTIONAL TO THE DIFFERENCE BETWEEN THE VOLTAGES OF THE POSITIVE AND NEGATIVE SUPPLY TERMINALS TO COMPENSATE THE OUTPUT POTENTIAL AT SAID OUTPUT TERMINAL FOR VARIATIONS IN VOLTAGE OF THE POSITIVE AND NEGATIVE SUPPLY TERMINALS.