Inductive transducers for measuring displacement are divided into two group
s according to their measurement range. A variable air-gap type transducer
is widely used for a measurement small range. A conventional variable air-g
ap type transducer has high sensitivity but lacks a linear measurement rang
e. The air gap is also increased to maintain linearity as the measurement r
ange increases, which induces a loss of sensitivity. The proposed variable
overlap-area type transducer retains the original sensitivity and its linea
rity does not deteriorate in spite of variations of the measurement range.
The proposed transducer is a flexible system that can increase its measurem
ent range as well as maintain high sensitivity and linearity. The experimen
tal results obtained using the prototype indicate that the sensitivity is h
igher than 2200 mV(.)V(-1) mm(-1) and the linearity error is below +/-0.075
% in the range of +/- 200 mum.