LVDT stands for Linear Variable Differential Transformer (LVDT). The moving part of the LVDT is connected to a core rod. Inside the LVDT body there is a primary coil (in the middle) and two secondary coils (at both ends); the position of the core varies the induction in the two secondary coils. External or internal electronics then convert this signal into a DC output that is proportional to the position of the core. Since the core does not touch the coils, there is no contact so the output has infinite resolution.
LVDT displacement transducers are used in many different applications. The most common are in industrial production, where the need to know the position of e.g. a cutting tool is essential for the control system. Our transducers visited the depths of the oceans to measure the valve position and were in space to measure the deflection in a mirror. They are equally at home in your factory or laboratory!