Concept:L.V.D.T. stands for Linear Variable Differential Transformer, and its output voltage is linearly proportional to the core displacement within a limited operating range.
Explanation:An L.V.D.T. consists of one primary winding and two identical secondary windings placed symmetrically around a movable magnetic core.
When an AC supply is given to the primary, equal but opposite voltages are induced in the two secondary windings.
The output voltage is the difference between these secondary voltages, and its magnitude changes as the core is displaced from the null position.
For small movements, this differential output voltage varies in direct proportion to the displacement of the core.
Practically, this linear relationship holds accurately only for displacements up to
5Â mm.
Beyond
5Â mm, the output becomes non-linear, and the accuracy of displacement measurement is significantly reduced.
Hence, the L.V.D.T. is best suited for precise measurement of small displacements or positions.
Answer:The output voltage of an L.V.D.T. transducer is practically linear for displacements up to
5Â mm.
Therefore, the correct option is D (linear; 5 mm).