When the core of an LVDT is at the center position, the output voltage is zero.

• A. True
• B. False
• C. Increases
• D. Decreases

Answer: (A)

The output of an LVDT is a differential signal between its two secondary windings, and it is proportional to how far the core is from the center. When the core sits exactly in the middle, the magnetic coupling to both secondary windings is the same, so the voltages induced in the two secondaries are equal in magnitude but opposite in phase. Subtracting one from the other cancels the voltages, giving zero output. If the core moves toward one side, the balance is broken: one secondary voltage increases while the other decreases, producing a nonzero differential voltage that grows with displacement and indicates the direction of movement. So at the center position the output is zero, making the statement true.