What is Voltmeter – Basics, Working & It’s Application


In the world of electrical engineering and electronics, the voltmeter stands as a fundamental instrument for measuring electrical potential difference or voltage. Whether in laboratories, industrial settings, or household applications, voltmeters are indispensable tools for understanding and managing electrical circuits. Today, we shall discuss about voltmeters, exploring their definitions, key features, construction, working principles, various types, and diverse applications.

Definitions of Voltmeter

A voltmeter is a specialized electrical instrument used to measure the electrical potential difference between two points in an electrical circuit. It is calibrated to provide voltage readings in units such as volts (V) and millivolts (mV) and is essential for assessing the health and performance of electrical systems.

Features of Voltmeter

  • Voltage Range Selection: Voltmeters come with various voltage range settings, allowing users to measure a wide spectrum of voltages accurately.
  • High Input Impedance: A high input impedance ensures minimal impact on the circuit being measured, preventing excessive current flow.
  • Analog or Digital Display: Voltmeters can have either analog needle displays or digital screens, providing flexibility to suit user preferences.
  • Accuracy: Precision is paramount in voltage measurements, and quality voltmeters offer high accuracy levels.
  • Safety Features: Many voltmeters include safety features like overload protection and fused inputs to safeguard both the user and the instrument.

Construction of Voltmeter

Voltmeters consist of various components, including a voltage-sensing element (usually a coil or resistor), a display mechanism (analog or digital), and circuitry to convert the measured voltage into a readable format. The input terminals allow connection to the circuit being measured, while protective casings ensure safety and durability.

Working of Voltmeter

The operation of a voltmeter is based on Ohm’s law, which states that voltage (V) is equal to the product of current (I) and resistance (R): V = IR. A voltmeter is connected in parallel with the portion of the circuit where voltage measurement is desired. By having a high input impedance, it draws negligible current from the circuit, ensuring minimal disruption. The voltmeter then displays the voltage reading based on the current passing through it and the internal resistance.

Types of Voltmeter

There are two main types of voltmeters:

  • Analog Voltmeter
  • Digital Voltmeter

Analog Voltmeters

These use a moving needle or pointer on a scale to indicate voltage values.

Digital Voltmeters

These display voltage readings in digital numerical format, offering higher precision and ease of use.

Applications of Voltmeter

  • Household Electrical Testing: For checking household electrical outlets and appliances.
  • Automotive Diagnostics: To troubleshoot car electrical systems.
  • Industrial Equipment Maintenance: To monitor and maintain machinery.
  • Laboratory Experiments: In scientific research and experimentation.
  • Power Grid Monitoring: In the electrical power industry to assess grid health and stability.

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