Circuits having negative resistance characteristics

Claim 1

A CIRCUIT FOR PROVIDING A CRRENT-VOLTAGE CHARACTERISTIC HAVING A LINEAR NEGATIVE RESISTANCE PORTION OF PRESELECTED MAGNITDE BETWEEN FIRST AND SECOND POSITIVE RESISTANCE PORTIONS COMPRISING: FIRST AND SECOND TERMINALS BETWEEN WHICH SAID CURRENT-VOLTAGE CHARACTERISTIC IS PROVIDED; A SORCE OF POTENTIAL HAVING ONE OF ITS TERMINALS CONNECTED TO SAID SECOND TERMINAL; FIRST AND SECOND TRANSISTORS OF OPPOSITE CONDCTIVITY TYPES EACH HAVING AN EMITTER, A COLLECTOR AND A BASE; THE COLLECTOR AND BASE OF SAID FIRST TRANSISTOR BEING DIRECTLY CONNECTED TO SAID FIRST AND SECOND TERMINALS, RESPECTIVELY; THE EMITTER OF SAID FIRST TRANSISTOR BEING DIRECTLY CONNECTED TO THE EMITTER OF SAID SECOND TRANSISTOR; THE COLLECTOR OF SAID SECOND TRANSISTOR BEING DIRECTLY CONNECTED TO THE OTHER TERMINAL OF SAID SOURCE OF POTENTIAL; RESISTANCE MEANS CONNECTED BETWEEN THE BASE OF SAID SECOND TRANSISTOR AND SAID OTHER TERMINAL OF SAID SOURCE OF POTENTIAL FOR PROVIDING A SUBSTANTIALLY CONSTANT CURRENT FLOW THEREBETWEEN; AND A FEEDBACK RESISTOR CONNECTED BETWEEN THE COLLECTOR OF SAID FIRST TRANSISTOR AND THE BASE OF SAID SECOND TRANSISTOR FOR DECREASING THE BASE CURRENT OF SAID SECOND TRANSISTOR IN RESPONSE TO AN INCREASE IN VOLTAGE BETWEEN SAID FIRST AND SECOND TERMINALS; SAID FEEDBACK RESISTOR HAVING A RESISTANCE VALUE EQUAL IN MAGNITUDE TO THE COMMON EMITTER CURRENT GAIN OF SAID SECOND TRANSISTOR TIMES SAID PRESELECTED MAGNITUDE OF SAID LINEAR NEGATIVE RESISTANCE.