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GP-EC-0MBTTEDElectronicsReady

ngspice analog circuit simulation

An ngspice 47 study of a common-emitter transistor amplifier covering bias, gain, bandwidth, transient response, noise, distortion, temperature, supply variation, and component tolerance.

ngspice analog circuit simulation project visual
GP-EC-0MBTTED · Electronics
  • ngspice 47
  • Python
  • NumPy
  • Matplotlib
  • Jupyter

Software compatibility

ngspice 47 only

The netlists, models, controls, and result scripts are prepared for ngspice 47. LTspice, PSpice, Multisim, and Cadence schematic project files are not included.

Project definition

Problem statement

Analogue-circuit behaviour changes with bias, device model, source and load impedance, frequency, signal level, temperature, and component tolerance.

Project objectives

  • Model a 12 V common-emitter NPN amplifier in native ngspice 47.
  • Verify the operating point and midband gain against hand calculations.
  • Measure AC bandwidth, transient response, noise, and harmonic distortion.
  • Study input amplitude, temperature, supply voltage, and component tolerance.
  • Produce reproducible raw data, summary tables, plots, and verification evidence.

Project structure

Project components

01

Circuit model

Defines the divider-biased common-emitter stage, source, load, coupling capacitors, split emitter resistance, and documented educational transistor model.

02

Netlist generator

Creates consistent ngspice cases from the versioned study configuration.

03

Simulation runner

Executes operating-point, AC, transient, noise, amplitude, temperature, supply, and tolerance studies.

04

Result analyser

Calculates bias, gain, phase, cut-off frequencies, distortion, noise, sensitivity, and statistical ranges.

05

Verification suite

Checks analytical values, netlist contents, result counts, repository completeness, and reproducibility.

Methodology

Project workflow

  1. 01
    Generate

    The Python generator writes the baseline and parameter-study netlists.

  2. 02
    Simulate

    The pinned ngspice 47 container runs 214 cases and exports 226 raw data files.

  3. 03
    Analyse

    Python calculates performance metrics and builds tables and plots.

  4. 04
    Compare

    Operating point and gain are checked against independent hand calculations.

  5. 05
    Verify

    Unit tests, document audits, smoke tests, and repository validation confirm the delivery.

Demonstration scenario

The amplifier is checked at its 12 V baseline, where it produces 27.50 dB gain at 1 kHz with lower and upper cut-offs of 7.59 Hz and 3.71 MHz. The study then measures distortion, noise, three temperatures, three supplies, and 200 fixed-seed tolerance samples.

Engineering

Tools and method

Tools
The project uses ngspice 47, Python, NumPy, Matplotlib, Jupyter for subject analysis, simulation, and results.
Environment
ngspice 47 is built from its verified official source archive in a pinned Ubuntu 26.04 Docker image.
Circuit
A 12 V divider-biased common-emitter amplifier uses a documented generic NPN educational model, 600 ohm source, and 10 kohm load.
Automation
Python generates cases, runs ngspice in batch mode, parses outputs, calculates metrics, and produces plots.
Verification
Hand calculations, fixed-seed tolerance sampling, unit tests, file-count checks, and a complete smoke test are included.

Testing

Evaluation

Evaluation measures

  • Collector bias voltage and current
  • Midband gain and phase at 1 kHz
  • Lower and upper cut-off frequencies
  • Transient waveform and total harmonic distortion across seven input amplitudes
  • Integrated output and input-referred noise
  • Temperature, supply, and 200-sample component-tolerance sensitivity

Project boundaries

  • Only ngspice 47 netlists and result files are delivered.
  • The generic transistor model supports reproducible education and is not a claim about a particular manufactured device.
  • Layout parasitics, ageing, thermal coupling, manufacturing variation beyond the defined tolerance model, and hardware measurement are outside the completed scope.
  • Physical construction requires component ratings, electrical safety, measurement, and qualified review.

Included

  1. 01Native ngspice 47 common-emitter amplifier netlist
  2. 02Operating-point, AC, transient, noise, distortion, temperature, supply, and tolerance analyses
  3. 03214 completed simulation cases and 226 raw result files
  4. 04Gain, bandwidth, waveform, noise, distortion, sensitivity, and tolerance plots
  5. 05Complete project files, models, calculations, and analysis material in a private GitHub repository
  6. 0674-page project documentation in PDF and editable Word formats
  7. 0716-page setup and usage guide

Project record

No information is collected on this page.

Permanent project ID
GP-EC-0MBTTED
Catalogued
22 Aug 2026
Completed
22 Aug 2026
Verified
22 Aug 2026
Demonstration
Included in repository

Handover

After purchase

  1. 01
    Payment is confirmed

    The project is marked unavailable and cannot be purchased again.

  2. 02
    Repository access is granted

    The buyer's submitted GitHub account receives access to the private repository.

  3. 03
    The purchase record is delivered

    The certification sheet is prepared from the reviewed buyer details and sent privately by email.