What Is an LVDT? Principles, Uses and Benefits

• May 22, 2025

What Is an LVDT? Principles, Uses and Benefits

LVDT (Linear Variable Differential Transformer) is a highly accurate and reliable electromechanical transducer that converts linear motion into an electrical signal. Operating on the principle of mutual induction, the LVDT offers frictionless performance, infinite resolution, and exceptional durability. It is widely used in industries such as aerospace, automotive testing, industrial automation, and materials research, anywhere precise, repeatable position feedback is essential. Whether you’re an engineer, technician, or student, understanding how LVDTs work is key to selecting the right sensor for high-resolution displacement measurement.

How Does an LVDT Work?

An LVDT consists of three main components:

• A primary coil centered between two secondary coils.
• A ferromagnetic core that moves linearly within the coil structure.

Here’s a basic overview of its operation:

1. An AC voltage is applied to the primary coil.
2. This generates an electromagnetic field, inducing voltages in the two secondary coils.
3. As the core moves, it changes the mutual inductance between the primary and each secondary coil.
4. The difference in voltage between the two secondary coils produces an output signal proportional to the core’s position.

Key Features and Advantages of LVDTs

• High Accuracy: Capable of measuring very small displacements with excellent repeatability.
• Robust Design: Suitable for harsh environments; can operate under extreme temperatures, pressure, or vibration.
• Wear-free Operation: The moving core does not physically contact the coils, reducing mechanical wear.
• Long Lifespan: Minimal maintenance and long-term reliability.

Common Applications of LVDTs

LVDTs are trusted across a wide range of industries for their precision, reliability, and ability to perform under challenging conditions. Here are some of the most common applications:

• Actuator Position Feedback in Aircraft Control Systems
  In aerospace systems, LVDTs are essential for real-time monitoring of actuator positions, wing flaps, thrust reversers, and landing gear deployment. Their resistance to extreme temperatures and vibrations makes them ideal for high-reliability applications in both commercial and military aircraft.
• Automotive Testing
  LVDTs play a crucial role in R&D and crash testing environments. They are used to measure dynamic parameters such as suspension travel, steering position, brake pedal movement, and chassis deformation. Their ability to deliver accurate data at high speeds supports the development of safer, more responsive vehicles.
• Position Sensing in Robotic Arms and Actuators
  In manufacturing and process control, LVDTs provide precise linear position feedback for robotic arms, CNC machine tools, and valve actuators. Their durability and non-contact operation reduce maintenance needs and ensure long-term accuracy in repetitive operations.
• Structural Displacement Monitoring in Bridges and Tunnels
  LVDTs are mounted on structural joints and support elements in bridges, tunnels, and dams to measure shifts, deflections, or settling over time. The data supports real-time structural health monitoring and preventive maintenance.
• OEM in Medical Devices
  In the medical field, LVDTs are used in devices requiring fine motion control, such as robotic surgical tools, prosthetic testing rigs, and rehabilitation machines. Their smooth, contactless operation ensures precise measurement without mechanical noise or wear—critical for sensitive healthcare environments.

Comparison between LVDT vs Other Displacement Sensors

Learn more about potentiometer basics and the difference between LVDT and potentiometer.

Choosing the Right LVDT for Your Application

Selecting the right LVDT is critical to ensuring accurate and reliable performance in your specific use case. Since LVDTs are used in a wide range of environments—from clean laboratory settings to rugged industrial sites—it’s important to evaluate the sensor’s specifications against the demands of your application. Here are the key factors to consider:

• Measurement Range: From microns to several hundred millimeters.
• Environmental Conditions: Temperature, pressure, and exposure to contaminants.
• Mounting Requirements: Core actuation style (spring-loaded, captive, etc.).
• Signal Conditioning: Whether you need a standalone unit or built-in electronics. Learn more about the differences between AC LVDT and DC LVDT.

We offer a comprehensive range of displacement sensors including LVDT, potentiometer and draw wire sensor. Our sensors combine performance, durability, and ease of integration to meet the demands of today’s smart manufacturing systems.

Not sure which displacement sensor is right for your application?
Contact MeasureX to speak with our sensor experts. We’ll help you choose the most suitable solution or a custom-configured displacement sensor for your application.