Understanding LVDT: Principles, Materials, and Applications

The Linear Variable Differential Transformer (LVDT) is a type of electrical transformer used for measuring linear displacement. Its robust, contactless design ensures precise measurements over a wide range of environments.

LVDTs operate on mutual induction principle. A movable core changes the inductance balance between two secondary coils, which is translated into a voltage proportional to the core's position.

The core of an LVDT is typically made from nickel-iron alloy. This material is chosen for its high permeability and low hysteresis, which contribute to the sensor's accuracy and repeatability.

To obtain usable data from an LVDT, signal conditioning is necessary. It involves demodulating, filtering, and amplifying the output to convert it into a high-quality signal.

LVDTs are used in diverse applications, such as aerospace for valve positioning, in civil engineering for structural health monitoring, and in the medical field for force feedback in robotic surgery.

Compared to potentiometers, LVDTs offer non-contact measurement, which eliminates wear and tear, leading to longer life and higher reliability. Their dynamic response is also superior.

Modern LVDTs now feature digital interfaces, and improved signal processing capabilities. Miniaturization has also allowed LVDTs to be used in applications where space is at a premium.