Transistorized low noise preamplifier having high resistive input impedance and low input capacity

Claim 1

A PREAMPLIFIER CIRCUIT FOR AMPLIFYING SIGNALS FROM A TRANSDUCER COMPRISING A FIRST TRANSISTOR HAVING EMITTER, BASE, AND COLLECTOR, MEANS COUPLING THE BASE OF SAID FIRST TRANSISTOR TO SAID TRANSDUCER, A SECOND TRANSISTOR COUPLED IN GROUNDED BASE CONFIGURATION AND HAVING EMITTER, BASE, AND COLLECTOR, THE EMITTER OF THE SECOND TRANSISTOR BEING DIRECTLY COUPLED TO THE COLLECTOR OF THE FIRST TRANSISTOR, A THIRD TRANSISTOR HAVING EMITTER, BASE, AND COLLECTOR, THE BASE OF THE THIRD TRANSISTOR BEING DIRECTLY COUPLED TO THE COLLECTOR OF THE SECOND TRANSISTOR, A FEEDBACK LOOP COUPLING THE COLLECTOR OF THE THIRD TRANSISTOR TO THE EMITTER OF THE FIRST TRANSISTOR, AN OUTPUT TERMINAL COUPLED TO THE COLLECTOR OF THE THIRD TRANSISTOR, AND BIAS MEANS COUPLED TO THE COLLECTOR AND BASE OF SAID FIRST TRANSISTOR, THE BASE OF SAID SECOND TRANSISTOR, AND THE EMITTER OF SAID THIRD TRANSISTOR TO FORWARD BIAS SAME.