Created by
Created October 20, 2012
Last modified December 19, 2012
Tags negative-resistance   oscillator  


Op Amp as a two-terminal Negative Resistance Circuit.
Linear slope should produce low distortion.


An op-amp implementation of an "absolute" negative resistor with N-shape IV curve.
The two resistors R1 & R2, and the op amp constitute a non-inverting amplifier with gain A = 2
that serves as the dynamic voltage source needed.

It amplifies the input voltage across the two input circuit terminals and applies it through the resistance R3 back to the input. For a positive input voltage, the current I = V/R3 is reversed and "pushed" back into the input source instead to be drawn from it as in the case of positive resistance R3.

The circuit as though converts the "positive resistance" R into negative one by inverting the current direction; thus the name negative impedance converter with current inversion (INIC).

The input port of the circuit can be connected into another network as if it was a negative resistance component.

Select an Op-Amp that operates in the frequency range you want, a few resistors, & tank circuit.

This should still work with V1 output Grounded.


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