Question

Compare primary and secondary transducer (any two points).

Answer 1

Primary transducer	Secondary transducer
The device which converts physical quantity into a mechanical displacement is called primary transducers.	The device that converts the mechanical form into an electrical form is called secondary transducers.
Ex:Bourdon tube acting as a primary transducer senses the pressure and converts the pressure into displacement.No output is given to the input of the bourdon tube.So it is called primary transducer. Mechanical device can act as a primary transducer	Ex:The output of the Bourdon tube is given to the input of the LVDT.There are two stages of transduction, firstly the pressure is converted into a displacement by the Bourdon tube,then the displacement is converted into analog voltage by LVDT.Here LVDT is called secondary transducer. Electrical device can act as a secondary transducer.

Answer 2

i) Primary Transducer: The detector or sensing element which senses the physical phenomenon and converts it into a measurable quantity, whose output forms the input of another transducer is called a primary transducer. 

  ii) Secondary Transducer: A transducer which converts analogous output of primary transducer into an electrical quantity is called a secondary transducer.