Audio Electronics Calculator

A richly formatted, interactive command-line calculator for electronics engineers, audio enthusiasts, guitar pedal designers, and eurorack synthesizer builders. Skip the mental unit conversions — enter values the way you think about them (4.7k, 47u, 2.2M) and get auto-scaled, readable results.

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Features

• 61 calculations across 10 categories covering resistors, capacitors, inductors, filters, op-amps, oscillators, and more
• Intelligent unit parsing — accepts standard SI notation (4.7k, 47u) and EE notation (4k7, 2M2)
• Auto-scaled output — results automatically formatted in the most readable unit (e.g., 1.23 kΩ, 470 nF)
• Formula display — every result shows the underlying formula to reinforce understanding
• Eurorack-focused — includes 1V/oct converters, VCO/VCA/VCF, ADSR timing, MIDI conversion, and a power budget calculator
• Rich terminal UI — colored output, panels, and tables via Spectre.Console

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Requirements

• .NET 10.0 SDK or Runtime

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Installation & Running

# Clone or download the project, then navigate to the project directory
cd AudioElectronicsCalculator

# Run directly
dotnet run

# Or build and run the executable
dotnet build -c Release
./bin/Release/net10.0/AudioElectronicsCalculator

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Usage

Launch the application and navigate menus using arrow keys and Enter. Each calculation prompts you for the required values and displays formatted results.

Unit Input Syntax

You can enter component values in several formats:

Input	Value	Notes
4.7k	4,700	Standard SI suffix
4k7	4,700	EE notation
47u	0.000047	Microfarads, microhenries, etc.
47µ	0.000047	Unicode mu accepted
100n	0.0000001	Nanofarads, etc.
2.2M	2,200,000	Megaohms, etc.
1000	1,000	Bare number also accepted

Supported multipliers: p (10⁻¹²), n (10⁻⁹), u/µ (10⁻⁶), m (10⁻³), k (10³), M (10⁶), G (10⁹)

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Calculator Categories

1. Resistors

Calculation	Description
Series resistance	Total R for resistors in series
Parallel resistance	Total R for 2 or more resistors in parallel
Ohm's Law	Solves for V, I, or R given the other two
Voltage divider	Output voltage from R1, R2, and Vin
Power dissipation	Power from V and R, I and R, or V and I
Color code decoder	4-band and 5-band resistor color codes → resistance value

2. Capacitors

Calculation	Description
Series capacitance	Total C for capacitors in series
Parallel capacitance	Total C for capacitors in parallel
Capacitive reactance	Xc = 1 / (2πfC)
RC time constant	τ = RC
Charge/discharge voltage	Voltage across capacitor at time t
Stored energy	E = ½CV²

3. Inductors

Calculation	Description
Series inductance	Total L for inductors in series
Parallel inductance	Total L for inductors in parallel
Inductive reactance	XL = 2πfL
RL time constant	τ = L/R
Stored energy	E = ½LI²

4. Impedance & AC Analysis

Calculation	Description
RC series impedance	Z and phase angle for RC in series
RL series impedance	Z and phase angle for RL in series
RLC series impedance	Z, phase angle, and resonance analysis
RLC parallel impedance	Parallel RLC analysis
Resonant frequency	f = 1 / (2π√LC)
Q factor	Quality factor from R, L, C
Phase angle	Voltage vs. current phase relationship

5. Filters

Calculation	Description
RC low-pass cutoff	fc = 1 / (2πRC)
RC high-pass cutoff	fc = 1 / (2πRC)
RL low-pass/high-pass	fc = R / (2πL)
RLC band-pass	Center frequency and bandwidth
RLC band-stop (notch)	Notch frequency from L and C
Sallen-Key low-pass	2nd-order Sallen-Key with Q factor
Sallen-Key high-pass	2nd-order Sallen-Key with Q factor
State-Variable Filter	VCF topology used in eurorack modules
Multiple Feedback (MFB)	MFB low-pass with gain and Q
Q factor	Filter quality factor calculation

6. Op-Amp Configurations

Calculation	Description
Inverting amplifier	Gain = −Rf/Rin
Non-inverting amplifier	Gain = 1 + Rf/R1
Summing amplifier	Weighted sum of multiple inputs
Difference amplifier	Differential gain from R1 and R2
Instrumentation amplifier	Gain from R1, R2, Rgain
Integrator	Output voltage for given input and time
Differentiator	Output voltage for given dV/dt
Transimpedance amplifier	I → V conversion (TIA/current sense)

7. Comparators & Schmitt Triggers

Calculation	Description
Non-inverting Schmitt	Upper and lower threshold voltages
Inverting Schmitt	Threshold voltages for inverting topology
Hysteresis voltage	Vhys from R1, R2, and supply
Schmitt from supply	Threshold calculation from Vcc

8. Oscillators & VCO

Calculation	Description
555 astable	Frequency and duty cycle from R1, R2, C
555 monostable	Pulse width from R and C
1V/Oct converter	Pitch frequency from control voltage
MIDI ↔ frequency	Convert MIDI note number to/from Hz
Musical intervals	Frequency ratios for semitones and octaves
LC oscillator	Resonant frequency from L and C

9. Envelope Generators & VCA

Calculation	Description
ADSR timing	Attack/decay/release times from RC constants
Exponential envelope	Voltage at time t on exponential curve
OTA-based VCA	Gain for LM13700 / CA3080 OTA circuits
Linear vs. exponential VCA	Response curve comparison

10. Utility & Signal

Calculation	Description
Decibels	Voltage and power ratio ↔ dB conversion
Diode reference	Forward voltage drop table by diode type
Zener clamp	Clamping voltage and power dissipation
Rectifier output	DC output for half-wave, full-wave, and bridge rectifiers
BJT calculations	Beta/gain, voltage divider bias point
JFET drain current	Id from Shockley equation (Idss, Vp)
LM317 regulator	Output voltage from R1, R2, and Vref
Ripple voltage	Ripple on filtered supply from C, I, and frequency
Eurorack power budget	Per-rail current budget with +12V/−12V/+5V status
Wheatstone bridge	Balance check and unknown resistance solver

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Project Structure

AudioElectronicsCalculator/
├── AudioElectronicsCalculator/              # Main application
│   ├── Program.cs                           # Entry point and top-level menu
│   ├── AudioElectronicsCalculator.csproj    # .NET 10.0 project file
│   ├── Core/
│   │   ├── UnitParser.cs                    # SI/EE unit input parsing
│   │   └── UnitFormatter.cs                 # Auto-scaling result formatting
│   ├── Menus/
│   │   └── MenuHelpers.cs                   # Prompt and display helpers (Spectre.Console)
│   └── Calculators/
│       ├── Resistors.cs
│       ├── Capacitors.cs
│       ├── Inductors.cs
│       ├── ImpedanceAC.cs
│       ├── Filters.cs
│       ├── OpAmps.cs
│       ├── Comparators.cs
│       ├── Oscillators.cs
│       ├── EnvelopeVca.cs
│       └── Utility.cs
└── AudioElectronicsCalculator.Tests/        # Unit tests (TUnit)
    ├── AudioElectronicsCalculator.Tests.csproj
    ├── ResistorMathTests.cs
    ├── CapacitorMathTests.cs
    ├── InductorMathTests.cs
    ├── ImpedanceMathTests.cs
    ├── FilterMathTests.cs
    ├── OpAmpMathTests.cs
    ├── ComparatorMathTests.cs
    ├── OscillatorMathTests.cs
    ├── EnvelopeMathTests.cs
    └── UtilityMathTests.cs

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Dependencies

Package	Version	Purpose
Spectre.Console	0.54.0	Rich terminal UI (colors, tables, prompts)
TUnit	1.19.57	Unit test framework (test project only)

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Extending the Application

The modular structure makes adding new calculations straightforward:

1. Add a new static method to the appropriate Calculators/*.cs file (or create a new file for a new category)
2. Use MenuHelpers.AskValue() to gather user input with automatic unit parsing
3. Use UnitFormatter.FormatXxx() methods to display auto-scaled results via MenuHelpers.ShowResult()
4. Wire the new menu entry in Program.cs

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Target Audience

• Electronics engineers doing quick component calculations
• DIY audio and guitar pedal designers
• Eurorack synthesizer module builders
• Students learning analog electronics

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License

This software is covered by the terms of the Mozilla Public License 2.0.