A Linear Variable Differential Transformer (LVDT) is a type of electromechanical transducer used to convert linear displacement or position into an electrical signal. It is a common type of position sensor that can accurately measure the distance or displacement of an object. LVDTs are widely used in various industrial and scientific applications where precise position sensing is required.
The LVDT consists of three coils: one primary coil and two secondary coils, all wound on a tube-like ferromagnetic core. The primary coil is typically driven with an alternating current (AC) voltage, which induces voltages in the two secondary coils. The arrangement of the coils and core is such that the induced voltages in the secondary coils change proportionally with the displacement of the core along its axis.
When the core is positioned at the center or null position, the output voltages of the two secondary coils are equal and opposite, resulting in a net output voltage of zero. As the core is moved from the null position due to the object's displacement, the voltage induced in one secondary coil increases, while the voltage in the other decreases, producing a differential output voltage that corresponds to the object's linear position.
LVDTs offer several advantages, including:
High accuracy: LVDTs are known for their precise measurements, making them suitable for applications that require fine control and high precision.
Non-contact operation: Since there is no physical contact between the core and the coils, LVDTs have excellent reliability and long operational life.
No electrical connection to the moving object: The core movement does not require any electrical connection, which can simplify the design and reduce wear and tear issues.
High linearity: LVDTs can provide a nearly linear relationship between the displacement of the core and the electrical output.
LVDTs find use in various fields, including automation, robotics, aerospace, quality control, displacement measurements, and many other industrial applications where accurate and reliable position sensing is essential.