impulso-mna 2.1.0

A package for the simulation of analog electronic circuits using Modified Nodal Analysis

impulso-mna

impulso-mna is a Python package for circuit simulation based on Modified Nodal Analysis (MNA). It provides a flexible and extensible framework for DC, AC, and transient analysis of electrical circuits, with a strong focus on clarity, composability, and performance.

The package is now in version 2.0.1.

The package is installed as impulso-mna but imported as:

import impulso

---

✨ Features

• Modified Nodal Analysis (MNA) core

• Unified framework for:

  • DC operating point analysis
  • AC small-signal analysis
  • Transient simulation

• Support for:

  • Resistors, capacitors, inductors
  • Independent voltage and current sources
  • Nonlinear components (e.g. diodes, BJTs)

• Companion models for transient analysis

• Extensible component API for custom devices

• Designed for readability and experimentation

---

💡 Motivation

impulso-mna was created to provide a fully Python-native alternative to existing (semi-)advanced circuit simulation tools.

Many available Python-based circuit simulators rely on external backends (such as SPICE engines). While powerful, these approaches often introduce:

• Additional installation complexity
• Platform-specific issues
• Indirect workflows (Python → external simulator → results back to Python)

This can make them harder to use, especially in iterative or programmatic contexts.

---

🐍 A pure Python approach

impulso-mna is implemented entirely in Python and depends only on numpy for numerical computations.

This design choice provides:

• Simple installation and portability
• Full transparency of the simulation process
• Direct access to all internal data structures

---

🔄 Tight integration with Python workflows

A key goal of this package is to make circuit simulation a first-class part of Python code, rather than an external tool.

Simulation results are directly available as Python objects, which makes it straightforward to:

• Integrate simulations into optimization loops
• Perform parameter sweeps programmatically
• Couple circuit models with other numerical or scientific workflows
• Build custom analysis pipelines

These workflows are often cumbersome or inefficient when using traditional simulator integrations.

---

🎯 Positioning

• Use impulso-mna for a minimal, stable foundation
• Use impulsox-mna when you need more control, flexibility, or want to experiment with advanced techniques

Together, they aim to provide a clean, Python-first ecosystem for circuit simulation without external dependencies.

---

📦 Installation

pip install impulso-mna

For development (editable install):

git clone https://github.com/<your-username>/impulso-mna.git
cd impulso-mna
pip install -e .

---

🚀 Quick Example

import impulso as imp

# Create a circuit
ckt = imp.Circuit()

# Add components
ckt.add(imp.Resistor("R1", n1=1, n2=0, value=1e3))
ckt.add(imp.VoltageSource("V1", n_plus=1, n_minus=0, value=5.0))

# Solve DC operating point
solution = ckt.solve_dc()

print(solution.node_voltages)

---

📊 Example Simulations

The repository includes several example simulations demonstrating the capabilities of the library.

1. Diode I–V Curve

Simulates the nonlinear current–voltage characteristic of a diode using DC sweep.

• Demonstrates:

  • Nonlinear solving
  • Operating point convergence

• Output: exponential I–V curve

---

2. NPN Transistor Output Characteristics

Generates a family of curves (Ic vs Vce) for different base currents.

• Demonstrates:

  • BJT modeling (e.g. Ebers–Moll)
  • Parameter sweeps

• Output: characteristic transistor curves including saturation behavior and output resistance (Early voltage).

---

3. Pulse Counting FM Detector

Implements a simple frequency-modulation detector based on pulse counting.

• Demonstrates:

  • Transient simulation
  • Time-domain signal processing

• Output: recovered modulation signal from pulse frequency

---

4. Dirac Pulse Driving an RC Network

Applies a Dirac-like pulse to an RC circuit and observes the response.

• Demonstrates:

  • Impulse-like excitation
  • Transient response of linear systems

• Output: exponential decay consistent with RC time constant

---

5 Relaxation oscillator

This is a relaxation oscillator as described in https://youtu.be/2a1I1X3RV0g. This is a hard circuit to simulate and takes more than than the other typical example scripts.

---

🧠 Design Philosophy

• Minimal but powerful: Focus on essential abstractions
• Explicit stamping: Components directly contribute to MNA matrices
• Unified API: Same interface across DC / AC / transient
• Extensibility first: Easy to implement custom components

---

🧩 Component Model

Each component contributes to the system via:

• Admittance / conductance
• Current injections
• Additional equations (for voltage sources, inductors, etc.)

Nonlinear components are handled through iterative solving (e.g. Newton-Raphson), with operating point linearization for AC analysis.

---

🔧 Development Workflow

Recommended setup:

pip install -e .[dev]

Typical structure:

.
├── impulso/
├── examples/
├── tests/
└── pyproject.toml

Run examples:

python examples/diode_curve.py

---

📈 Performance Notes

• Uses NumPy for linear algebra
• Designed to be efficient but still readable
• Profiling suggests convergence checks can be a bottleneck — optimizations welcome

---

🤝 Contributing

Contributions are welcome. Areas of interest include:

• Performance improvements
• Additional device models
• Better convergence strategies
• Documentation and examples

---

📄 License

MIT License (or your chosen license)

---

🏁 Roadmap

Here’s a revised Roadmap section that reflects a stable, maintenance-focused direction:

---

🎯 Scope & Philosophy

impulso-mna is intentionally designed as a minimal, foundational implementation of Modified Nodal Analysis (MNA).

Its purpose is to provide:

• A clear and correct reference implementation of MNA
• A lightweight engine for DC, AC, and transient simulation
• A clean and predictable API for circuit construction and analysis

The package prioritizes clarity, stability, and simplicity over feature breadth. It is deliberately kept:

• Easy to read and reason about
• Easy to extend for custom components and experiments
• Free from heavy abstractions, dependency injection, or complex infrastructure

This makes impulso-mna suitable both as a practical simulation tool and as a foundation for understanding and developing circuit solvers.

---

🚧 Advanced Features

Advanced functionality is provided in a separate package:

impulsox-mna (planned)

This package targets more demanding simulation scenarios and may include:

• More sophisticated semiconductor device models (e.g. advanced BJT/MOSFET models)
• Enhanced nonlinear convergence strategies
• Sparse and high-performance numerical backends
• RF and high-frequency analysis tools
• Noise analysis
• Extended simulation workflows and tooling

---

🔗 Relationship Between Packages

The two packages are intentionally independent and self-contained:

impulso-mna   → minimal, stable, and dependency-light MNA implementation
impulsox-mna  → advanced, feature-rich, fully independent simulator

Key design principles:

• No dependency relationship: impulsox-mna does not depend on impulso-mna
• Parallel design: both packages follow a similar structure and philosophy
• Full autonomy: each package is complete and usable on its own

This separation ensures that:

• impulso-mna remains compact, transparent, and stable
• impulsox-mna can evolve freely without introducing complexity into the core
• The base package avoids architectural overhead such as dependency injection or layered abstractions

---

🏁 Roadmap

impulso-mna is intended to remain a stable and minimal core package. Its functionality is largely complete and will not significantly expand over time.

Future development will focus on:

• Bug fixes and correctness improvements
• Code quality, readability, and maintainability
• Minor usability enhancements where appropriate

No major new features or architectural changes are planned for this package.

More advanced functionality and experimental features will be developed separately in impulsox-mna.

---

📦 Requirements

▶️ Core (runtime)

The core of impulso-mna is intentionally lightweight and depends only on a small set of packages:

• numpy — numerical computations and matrix operations

These are the only dependencies required to use the simulator itself.

---

📊 Optional (examples & visualization)

The following packages are used for running examples and visualizing results:

• matplotlib — plotting simulation results
• quantiphy — formatted physical quantities

matplotlib brings in several supporting dependencies (e.g. cycler, kiwisolver, pillow, etc.).

---

🧪 Development & testing

For development, testing, and contributing:

• pytest — test framework
• pluggy, iniconfig, Pygments — pytest dependencies

---

🛠 Build system

• setuptools
• wheel

---

🔗 Development note on impulso-mna

During development, you may encounter setups that include:

-e git+https://github.com/kvdijken/impulso-mna.git@<commit>#egg=impulso

This is only for development and comparison purposes.

• impulsox-mna does not depend on impulso-mna
• Both packages are fully independent implementations

---

⚙️ Installation

Minimal installation

pip install impulso-mna

---

Development environment

To reproduce the full development setup:

pip install -r requirements.txt

---

📝 Notes

• Runtime dependencies are intentionally minimal
• Additional packages are only required for examples, testing, and development
• Future versions may formalize this split via optional dependency groups (e.g. extras_require)