Inductance Capacitance Meter

This project presents an Inductance-Capacitance (L-C) Meter designed and built as part of the Laboratory Practice and Projects module. This device is capable of measuring a wide range of inductance and capacitance values, making it an essential tool for electronics hobbyists and professionals.

Table of Contents

• Project Overview
• Features
• How to Use
• Hardware
  • Components
  • Circuit Design
  • PCB Design
• Software
• Theory of Operation
  • Inductance Measurement
  • Capacitance Measurement

Project Overview

The Inductance Capacitance Meter is a project developed to provide a simple and accurate solution for measuring the inductance of inductors and the capacitance of capacitors. The device uses an Arduino Pro Mini to control the measurement process and a 1.54-inch OLED display to show the results. It features dedicated modes for both inductance and capacitance measurement with selectable ranges for improved accuracy.

Features

• Dual Measurement Modes: Measures both inductance and capacitance.
• Multiple Ranges: Offers different measurement ranges for better precision.
• Clear Display: A 1.54-inch 128x64 I2C OLED screen displays the mode, range, and measured value.
• User-Friendly Interface: Operated by four buttons for power, mode selection, and range adjustment.
• Compact and Enclosed Design: Housed in a custom-designed enclosure for protection and ease of use.

How to Use

1. Power On: Press the Power Button to turn on the device. A welcome screen will be displayed.
2. Mode Selection: Use the "Mode" button to switch between Inductance and Capacitance measurement modes.
3. Range Selection: Use the "Range Up" and "Range Down" buttons to select the appropriate measurement range for the component.
4. Component Insertion: Connect the inductor or capacitor to the measuring probes.
5. Result Display: The measured value will be shown on the OLED display.

Hardware

Components

• Microcontroller: Arduino Pro Mini
• Display: 1.54 inch 128x64 I2C OLED
• Operational Amplifier: TL072 (for integrator)
• Comparator: LM393 & LM311
• Transistor: BC547B
• Various resistors and capacitors for the measurement circuits.

Circuit Design

The device comprises two main measurement circuits: one for inductance and one for capacitance.

Inductance Measurement Circuit: This circuit is based on a Colpitts oscillator. The unknown inductor resonates with a known capacitor, and the resulting oscillation frequency is measured. This frequency is then converted to a voltage to calculate the inductance.

Capacitance Measurement Circuit: This circuit works by charging the unknown capacitor and comparing its voltage to a reference. An integrator circuit is used to generate a ramp voltage, and by sampling this voltage at a specific time, the capacitance is determined.

PCB Design

A custom PCB was designed to house all the components, ensuring a compact and reliable build.

Software

The device is controlled by an Arduino sketch running on the Arduino Pro Mini. The software is responsible for:

• Reading button inputs for mode and range selection.
• Controlling the measurement circuits.
• Calculating the inductance or capacitance based on the measured values.
• Displaying the results on the OLED screen.