The both the secondary windings are connected in such a way that resulted output is the difference between the voltages of two windings. An input AC signal on the primary winding induces a corresponding signal on each of the secondary windings. This is the null position of the LVDT. When the external applied force moved the core down word the induce voltage E2 in secondary coil S2 increased but the induce voltage in S1 is decreased in magnitude , they are still out of phase due to which there is some net voltage are induce at out put terminals A and B, whose magnitude is E2 – E1. It is used to control the jet engine in aircrafts. It can operate over a temperature range from -650C° to 600C°. . The output voltage of secondary S 1 is ES 1 and that of secondary S 2 is ES 2. Since, both the windings are connected in the series opposition the output voltage of the winding (E o) will be the difference of the two voltages i.e. Figure 1: Linear variable differential transformer (LVDT) The secondary windings are wound out of phase with each other. When the core is moved off center, the voltage in the secondary toward which the core is moved increases, while the opposite voltage decreases. An alternating current drives the primary and causes a voltage to be induced in each secondary proportional to the length of the core linking to the secondary. At the centre of the position measurement stroke, the two secondary voltages of the displacement transducer are equal but because they are connected in opposition the resulting output from the sensor is zero. [CDATA[// >