• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar
  • Skip to footer

Sensor Tips

Sensor Product News, Tips, and learning resources for the Design Engineering Professional.

  • What’s Hot
    • Development Tools
    • Energy Harvesting
    • Market Research
    • Packaging
    • Sensor Fusion
    • Sensor-specific software
    • Signal Conditioning
    • Touch Sensing
    • Wireless
  • Motion Sensing
  • Vision systems
    • Smart cameras
    • Vision software
    • Lighting
    • Optics
  • Pressure
  • Speed
  • Temperature
  • Suppliers
  • Video
  • EE Learning Center

How is LVDT technology used for sensing?

February 15, 2021 By Randy Frank

Linear variable-differential transformer (LVDT) technology’s capability to accurately measurement linear movement is used to provide a position to electrical output for pressure, acceleration and force measurements. For example, in a pressure sensor, the sensing element is a diaphragm that moves a rod or cylindrical core inside the coils of a differential transformer to change the output voltage by changing the inductances of the coils in equal but opposite amounts.Source: Automotive Electronics Handbook, Chapter 2

An alternating current (AC) voltage source (typically in the kilohertz range) energizing the primary winding, results in induced voltages in each of the secondary windings. Since the windings are connected in series opposing, the equal but opposite output of each winding tends to cancel except for a small residual value called the null voltage. For a pressure sensor, the pressure applied to the diaphragm causes the core to move from its null position, so the coupling between the primary and the secondaries is no longer equal. The resulting output varies linearly and has a phase change of 180° from one side of the null position to the other.

Since the core and coil structures are not in physical contact, essentially frictionless movement results.

Signal conditioning to achieve a useful output includes an oscillator for the supply voltage, circuitry to transform the constant voltage to a constant current, an amplifier with a high input impedance for the output, a synchronous demodulator and a filter designed for quasistatic or dynamic measurements.

In addition to AC operated units, DC LVDTs powered by uni- or bi-polar DC voltages are also available that have their signal conditioning built into them from companies such as TE Connectivity.

Filed Under: Featured, Frequently Asked Question (FAQ), LVDT, Pressure Sensor Tagged With: TE Connectivity

Primary Sidebar

DesignFast

Component Selection Made Simple.

Try it Today
design fast globle

Subscribe to our Newsletter

Randy Frank delivers weekly sensor industry news, sensor resources, new sensor product innovations and more.

Subscribe Today

EE TRAINING CENTER CLASSROOMS

“ee

“ee

“ee

“ee

“ee

RSS Current EDABoard.com discussions

  • How can I explan this simple PWM creator Circuit
  • Can I use a Virtual clock instead of using a create_clock?
  • MCLR as digital input is resetting the device
  • Symmetrical Fully Differential Amplifier Layout
  • What is the DC voltage rating of this Y2 capacitor?

RSS Current Electro-Tech-Online.com Discussions

  • NTC flakey
  • Diode that only allows continuity at 13.5v?
  • Can two N-Channel MOSFETs be connected in series to perform a "AND" function?
  • Cycle Indicator Lights
  • #MEASURING OUTPUT VOLTAGE# Ideal laboratory power supply - YOURS requirements


SensorTips Videos

RSS Featured White Papers

  • Implementing Position Sensors for Hazardous Areas & Safety
  • How New Rotary Sensor Technology Enables New Application Solutions
  • Magnetic sensor ensures safety features in depaneling machines

Follow us on Twitter

Tweets by SensorTips

Footer

EE WORLD ONLINE NETWORK

  • DesignFast
  • EE World Online
  • EDA Board Forums
  • Electro Tech Online Forums
  • Microcontroller Tips
  • Analog IC Tips
  • Connector Tips
  • Power Electronic Tips
  • Test and Measurement Tips
  • Wire and Cable Tips
  • 5G Technology World

SENSOR TIPS

  • Subscribe to our newsletter
  • Advertise with us
  • Contact us
  • About us
Follow us on TwitterAdd us on FacebookFollow us on YouTube Follow us on Instagram

Copyright © 2021 · WTWH Media LLC and its licensors. All rights reserved.
The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media.

Privacy Policy