It converts one form of energy to another, usually to an electrical signal.

This signal usually represents a variable characteristic of the system that is to be controlled.

Often this signal is very small and has to be amplified.

Transducers are can be used in Wheatstone bridge circuits.

The most important transducer characteristics are:

(1) Resolution. The smallest input that it can respond to.

(2) Range. The total range of inputs that it can respond to.

(3) Bandwidth. The lowest frequency is usually D.C. and the highest is the -3 dB point.

(4) Response time. The time taken for the output to rise to a specified value in response to a step change at the input.

(5) Accuracy. The closeness of the measured value to the actual value.

(6) Sensitivity. The rate change of the output of the system as the input changes.

(7) Linearity. The linear relationship between the input and the output of the system.