# Circuit Idea/Bistable Mode of Current Inversion NIC

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Investigating the Bistable Mode of Negative Impedance Converters with Current Inversion

Circuit idea: Making the positive feedback dominate over the negative one.

INIC operating in bistable mode is a current-driven N-shaped true negative resistor.

## Introduction

### How to investigate the bistable mode of current inversion NIC

Fig. 1a: A hysteresis IV curve of current-driven INIC.

Fig. 1b: An N-shaped IV curve of voltage-driven INIC.

## Investigating the circuit at ideal driving conditions

### Increasing the input current

#### Negative input current, negative output voltage

Fig. 2a: Scanning the left bottom part (0 - 1) of the curve.

Fig. 2b: Sinking a current from INIC.

#### Zero input current, negative output voltage

Fig. 3a: Investigating the point 1 of the curve.

Fig. 3b: Sinking no current from INIC.

#### Positive input current, negative output voltage

Fig. 4a: Scanning the left top part (1 - 2) of the curve.

Fig. 4b: Injecting a current to INIC.

#### Voltage jump upward

##### ...start...

Fig. 5-1a: Investigating the starting point of the voltage jump.

Fig. 5-1b: Making the op-amp "jump" to the positive rail.
##### ...middle...

Fig. 5-2a: Scanning the top jumping path (2 - 3).

Fig. 5-2b: The op-amp "jumps" to the positive rail.
##### ...final

Fig. 5-3a: Investigating the final point of the voltage jump upward.

Fig. 5-3b: The op-amp "calms down" at the positive rail.

#### Positive input current, positive output voltage

Fig. 6a: Scanning the right top part (3 - 4) of the curve.

Fig. 6b: Injecting a big current to INIC.

### Decreasing the input current

#### Positive input current, positive output voltage

Fig. 7a: Scanning the right top part (4 - 5) of the curve.

Fig. 7b: Injecting a current to INIC.

#### Zero input current, positive output voltage

Fig. 8a: Investigating the point 5 of the curve.

Fig. 8b: Injecting no current to VNIC.

#### Negative input current, positive output voltage

Fig. 9a: Scanning the right bottom part (5 - 6) of the curve.

Fig. 9b: Sinking a current from INIC.

#### Voltage jump downward

##### ...start...

Fig. 10-1a: Investigating the starting point of the voltage jump.

Fig. 10-1b: Making the op-amp "jump" to the negative rail.
##### ...middle...

Fig. 10-2a: Scanning the bottom jumping path (6 - 7).

Fig. 10-2b: The op-amp "jumps" to the negative rail.
##### ...final

Fig. 10-3a: Investigating the final point of the voltage jump downward.

Fig. 10-3b: The op-amp "calms down" at the negative rail.

#### Negative input current, negative output voltage

Fig. 11a: Scanning the left bottom part (7 - 0) of the curve.

Fig. 11b: Siniking a big current from INIC.