Glossary · Sensors and measurement
Linear variable differential transformer (LVDT)
Also known as: LVDT, LVDT sensor
German: Induktiver Wegaufnehmer (LVDT)
In measurement technology, a linear variable differential transformer (LVDT) is an inductive displacement sensor with one primary and two secondary coils and a movable core; the position of the core changes the differential voltage of the secondary coils in proportion to the displacement.
- Sensors
In one sentence
An LVDT is an inductive displacement sensor whose movable core changes the differential voltage of two coils in proportion to the travel.
Example
An LVDT measures the spool position of a hydraulic servo valve and feeds it back to the valve electronics.
How it applies
- Engineering: LVDTs work without contact between core and coils, which gives them long life, high resolution and robustness. They need AC excitation and signal conditioning, either external or integrated in the sensor.
- Commissioning: Set the core position at the electrical zero and scale the output to the mechanical stroke.
- Maintenance: Mechanical alignment of core and coil body is important; bent core rods cause wear and errors.
- Documentation: Record the zero adjustment and the signal conditioner settings. Replacing an LVDT without these data often leads to incorrect positions.
LVDT vs. the AI transformer
The word transformer in LVDT refers to the electrical transformer principle of coupled coils. It has nothing to do with the Transformer architecture of language models, which this site's AI glossary describes.