LINEAR VARIABLE DIFFERENTIAL TRANSFORMER (LVDT)

This is an inductive displacement transducer sometimes used in pressure, displacement and force transducers. Sensitivity for LVDTs is much higher than for strain gauges but the processing apparatus is more complex. There are various types but the commonest has a primary coil wound around a sliding metal core with a secondary winding around the two ends of the core. As the core is displaced the voltage induced in the secondary winding changes such that the output voltage increases as the core moves to each side of the centre position and the phase changes by 180 degrees as it passes through the centre. A phase sensitive detector is required to convert the signal into a displacement. In pressure transducers the sliding core is connected to the pressure diaphragm.

Content and Design Copyright 2000 Dr. Malcolm C Brown.  See Title Page for more details