Inductance-Capacitance Meter AVR

Nobcha LC Meter – Arduino-Based Precision LC Analyzer

The Nobcha LC Meter is a compact and highly effective instrument for measuring inductance (L) and capacitance (C), based on a proven Franklin oscillator principle combined with microcontroller processing. This design offers an excellent balance between simplicity, accuracy, and practical usability for everyday electronics work.

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Overview

This LC meter uses a 74HCU04-based Franklin oscillator together with a microcontroller (Arduino platform) to determine component values by measuring frequency changes in an LC resonant circuit.

By inserting the component under test into the oscillator tank circuit, the system measures the resulting frequency shift and calculates the corresponding inductance or capacitance. This method allows accurate measurement using a relatively simple and low-cost design.

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How It Works

• The internal oscillator generates a stable frequency using a reference LC circuit
• When a component is connected, the oscillation frequency changes
• The microcontroller measures this frequency and calculates the value
• Results are displayed directly in standard units (nH, µH, pF, etc.)

This approach effectively converts an analog impedance measurement into a frequency-based calculation, which is ideal for digital processing and improves measurement stability.

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Key Features

• Accurate L & C Measurement
  Reliable measurement of inductors and capacitors using resonance-based technique
• Franklin Oscillator Design
  Stable and proven method widely used in DIY and professional LC meters
• Microcontroller-Based Processing
  Fast calculations with direct digital readout
• Calibration System
  Simple calibration using a known reference capacitor ensures consistent accuracy
• Wide Measurement Capability
  Suitable for RF coils, general inductors, and various capacitor types
• Compact and Efficient Design
  Minimal components while maintaining strong performance

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Performance & Advantages

• Provides direct readable values (µH, nH, pF) without complex interpretation
• Particularly useful for coil winding, RF circuits, and filter design
• More practical for everyday measurements compared to interpreting impedance graphs
• Handles a wide range of inductance values effectively, even where other tools may struggle

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Applications

• Measuring and matching inductors and capacitors
• RF circuit design and tuning
• DIY electronics and prototyping
• Repair and troubleshooting
• Educational use and experimentation

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Design Background

The LC meter is based on a classic measurement technique originally developed using analog oscillators and later adapted to microcontrollers. The integration of the Franklin oscillator with digital frequency measurement allows a simple yet powerful instrument suitable for both hobbyists and advanced users.

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What’s Included

• Fully assembled and tested Nobcha LC Meter
• Ready for immediate use

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Notes

• Best accuracy is achieved after proper calibration
• Extremely small inductance values may be affected by stray wiring inductance
• Measurement frequency is typically in the low MHz range, ideal for HF applications

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The Nobcha LC Meter is a practical and reliable tool that transforms a classic measurement principle into a modern, easy-to-use instrument—perfect for anyone working with electronic components, especially in RF and analog design.