What happens to the secondary output voltage of an LVDT when the core is displaced?

The correct choice indicates that the secondary output voltage of a Linear Variable Differential Transformer (LVDT) increases or decreases when the core is displaced.

This is a fundamental characteristic of how an LVDT operates. An LVDT consists of a primary coil and two secondary coils arranged symmetrically around it. When the magnetic core within the LVDT is displaced from its null position (the position where the output voltage is zero), the magnetic coupling changes between the primary coil and the secondary coils.

As a result, the output voltage produced across the secondary coils becomes unbalanced, leading to an increase or decrease in the voltage level depending on the direction in which the core has moved. This variation in the secondary output voltage is proportional to the displacement of the core, which allows for precise measurement of linear position.

This principle is widely utilized in various applications, such as measuring displacements and controlling systems in industrial settings. The key takeaway is that the core's displacement directly alters the secondary output voltage, reinforcing the relationship between mechanical movement and electrical output in LVDTs.