TRANSDUCERS

Basically transducer is defined as a device which converts energy or information from one from to another.These are widely used or information from one from to another.These are widely used in measurement work because all quantities that need to be measured,cannot be displayed as easily as others.A better measurement of a quantity can usually be made if it may be converted to another form which is more conveniently or accurately displayed.For example,the common mercury thermometer converts variations in temperature into variations in the length of a column of mercury.Since the variation in the length of a column is rather simple to measure,the mercury thermometer becomes a convenient device for measuring temperature.On the other hand,the actual temperature variation is not as easy to display directly.

Thus the transducer is a device which provides a usable output in response to specific input measurand which may be physical or mechanical quantity,property or condition.The transducer may be mechanical,electrical,magnetic,optical,chemical,acoustic,thermal,nuclear,or a combination of any two or more of these.

Mostly quantities to be measured are non-electrical such as temperature,pressure displacement,humidity,fluid flow,speed etc.,but these quantities cannot be measured directly.Hence such quantities are required to be sensed and changed into some form for easy measurement.Electrical quantities such as current,voltage,resistance,inductance and capacitance etc.,can be conveniently measured,transferred and stored and,therefore ,for measurement quantities first and then measured.The function of converting nonelectrical quantity into electrical one is accomplished by a device called the electrical transducer.

Basically an electrical transducer is a sensing devices by which a physical,mechanical or optical quantity to be measured is transformed  directly,with a suitable mechanism,into an electrical signal(current,voltage or frequency).The production of these signals is based upon electrical effects which may be resistive,inductive, capacitive etc.,in nature