In a linear variable differential transformer (LVDT), 

• The LVDT consists of a primary winding P and two secondary winding S1 and S2 wound on a cylindrical former (which is hollow in nature and will contain core) .
• Both the secondary windings have equal number of turns and are identically placed on the either side of primary winding.

Important Points

•  LVDT (Linear Variable Differential Transformer) is the most widely used inductive transducer that coverts the linear motion into the electrical signal.
• Sensitivity of LVDT is mainly due to exact cancellation of secondary voltages
• The primary winding is connected to an AC source which produces a flux in the air gap and voltages are induced in secondary windings.
• A movable soft iron core is placed inside the former and displacement to be measured is connected to the iron core.