What is an LVDT and how does it work?

An LVDT (Linear Variable Differential Transformer) measures linear displacement without contact. It has a primary coil and two secondary coils wound on a cylindrical former with a movable magnetic core. AC excitation to the primary induces voltages in secondaries. When the core is centered, secondary voltages are equal and opposite (zero output). Core movement creates voltage imbalance proportional to displacement. LVDTs offer: infinite resolution (analog output), no friction wear, excellent linearity, and robust construction. Used in valve position sensing and precision measurements.