https://github.com/oonap0oo/ngspice_analog_circuit_simulation

Files for use with the ngspice circuit simulation software
https://github.com/oonap0oo/ngspice_analog_circuit_simulation

circuit ngspice simulation simulator spice

Last synced: 4 months ago
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Files for use with the ngspice circuit simulation software

• Host: GitHub
• URL: https://github.com/oonap0oo/ngspice_analog_circuit_simulation
• Owner: oonap0oo
• License: gpl-3.0
• Created: 2025-08-14T14:04:52.000Z (10 months ago)
• Default Branch: main
• Last Pushed: 2025-08-14T14:20:37.000Z (10 months ago)
• Last Synced: 2025-08-14T16:07:33.402Z (10 months ago)
• Topics: circuit, ngspice, simulation, simulator, spice
• Homepage:
• Size: 2.59 MB
• Stars: 0
• Watchers: 0
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# ngspice_analog_circuit_simulation

Files for use with the [ngspice](https://ngspice.sourceforge.io/) circuit simulation software

## Chua's circuit

This circuit desciption runs a version of Chua' circuit which shows chaotic behavior.

Circuit description file: [chua_circuit_6.sp](chua_circuit_6.sp)

This plot generated by ngspice shows two voltages in the circuit in a x-y plot.

![ngspice_chua_circuit_screenshot.png](ngspice_chua_circuit_screenshot.png)

The circuit description file was made based on this hand drawn schematic:

![chua_circuit_hand_dranw_schematic.png](chua_circuit_hand_dranw_schematic.png)

The amplifier in the circuit was modelled using a Voltage Dependent Voltage Source (E1), the output voltage is limited as in real world amplifiers using the table option.

The diodes and voltage sources introduce non-linearity which is a essential part of the circuit.

## Ring Modulator

This is a classic ring modulator with 4 diodes. The circuit multiplies two signals creating new sum and difference frequency components at it's output.

![Ring_Modulator.png](Ring_Modulator.png)

Schematic found on wikimedia: [https://commons.wikimedia.org/wiki/File:Ring_Modulator.PNG](https://commons.wikimedia.org/wiki/File:Ring_Modulator.PNG)

License: [https://creativecommons.org/licenses/by-sa/3.0/deed.en](https://creativecommons.org/licenses/by-sa/3.0/deed.en)

Modified by adding node numbers.

Circuit desciption file: [ring_mod.sp](ring_mod.sp)

In this example inputs to the circuit are signals at 1kHz and 1.2kHz, the output includes components at 2.2kHz (sum) and 200Hz (difference).

Output signal:

![ring_mod_screenshot3.png](ring_mod_screenshot3.png)

Frequency spectrum of output signal:

![ring_mod_screenshot1.png](ring_mod_screenshot1.png)

Input signals:

![ring_mod_screenshot2.png](ring_mod_screenshot2.png)