What is the use of TRANSDUCER in Electronic circuits?

An Electronic instrumentation system consists numbers of components to perform a measurement and record its result.Now a days a generalized measurement system consists of Three major components.
01) An input device
02) A signal conditioning or processing device
03) An output device

The input device receives the measure and/or the quantity under measurement and delivers a proportional or analogous electrical signal to the signal conditioning device.Here the signal is amplified,attenuated,filtered,modulated or otherwise modified in format acceptable to the output device.

The input quantity for most instrumentation systems is a "non-electrical quantity".In order to use electrical methods and techniques for measurement,manipulation or control,the non-electrical quantity is generally converted into an electrical form by a device called a "Tranducer"

We can define a Tranducer as a device which,when actuated transforms energy from one form to another.

The broad definition of a Transducer includes,for example device which convert Mechanical Force into an Electric Signal.These device form a very large and important group of Transducers commonly used in industrial instrumentation area.The Instrumentation Engineers and Technologist are therefore primarily concerned with this area of instrumentation.Many other physical parameters,such as heat,intensity of light,flow rate,liquid level,humidity and PH value may also be covered into electrical form by means of Transducers.These Transducers provide an output signal when stimulated by a Mechanical or non-mechanical input.A photoconductor converts a Thermocouple,converts heat energy into electrical voltage,a force produces a change of resistance in a strain gauge,an acceleration produces a voltage in a Piezo-electrical crystal and so on.In all cases,however,the electrical output is measured by standard methods,giving the magnitude of the input quantity in terms of a analogous output.

ELECTRIC TRANSDUCERS

The art of electrical measurements has been mainly used for measurement of electrical quantities but its value in making measurements of non-electrical quantities in this new era of Automation is rapidly growing.In order to measure non-electrical quantities a detector is used which usually converts the physical quantity into a displacement.

This displacement actuates an Electric Transducers,which acting as a secondary Transducer gives an output that is electrical in nature.The Electrical quantity so produce is measured by standard methods used for electrical measurements.The result (Electrical output) gives the magnitude of the physical quantity or condition being measured.

The electrical signal may be a current or a voltage or a frequency and production of these signals is based upon electrical effects which may be resistive,capacitive,inductive etc.. in nature.

The first stage of a system may be simply be called a Transducer stage instead of detector Transducer stage by redefining a Transducer.
A Transducer,in general form,may be defined as a device which converts energy from one form to another.However this definition has to be restricted many times especially in the field of electrical instrumentation.

Keeping this restriction in view,a Transducer may be defined as a device which convert a physical quantity or physical condition into an electrical signal.