Variable Inductance and' Variable Capacitance Transducers

VARIABLE INDUCTANCE TRANSDUCER

The variable inductance transducers work, generally, upon one of the  following three principles

(i) Change' of self inductance

(ii) Changeof'mutual inductance o and'

 (iii) Production of eddy currents Transducers working on principle of.

change of Self-Inductance

(i) change in number of turns, N,

(ii) change in geometric configurations, G,

and (iii) change in permeability, J.!

Inductive transducers are mainly used for measurement of displacement. The displacement to be measured is arranged to cause variation of any three variables in Eqn (4.1) and thus alter the self-inductance L by 6.L.Thedifferellt . types of inductive transducers for. measurement of translational and rotary displacements are shown in figure 4.1.

Differential output of Inductive Transducers

 (i) The sensitivity and accuracy are increased.

(ii) The output is less 'affected by external magnetic fields.

(iii) The effective variations due to temperature changes are reduced.

Transducers work.ingon principle of change of Mutual Inductance

An .inductance transducer working on the- principle variation of mutual inductance uses multiple coils. The mutual inductance between two coils is