What does LVDT stand for?

• A. Linear Variable Differential Transformer
• B. Linear Variable Direct Transformer
• C. Linear Voltage Differential Transformer
• D. Linear Variation Differential Transformer

Answer: (A)

LVDT stands for Linear Variable Differential Transformer, a displacement sensor that converts linear motion into an electrical signal without physical contact. Inside, a primary coil is excited with AC, and two secondary coils pick up voltages that depend on the position of a movable ferromagnetic core. As the core slides along the axis, the coupling to the two secondaries changes, producing a differential voltage that is proportional to displacement. At the center, the two outputs balance to give zero, and moving in either direction yields a voltage with magnitude corresponding to how far you’ve moved. The differential arrangement also helps reject noise, making it accurate and durable since there’s no wear from contact. The other phrasings don’t match the actual device name (they alter terms like Differential, Variable, or Transformer).