1 TRANSDUCER

2 Contents To understand the basic concept of Transducer To learn about Block diagram of transducer Different Applications of transducers

3 known to unknown What do you mean by ‘Measurement’ An act or the result of a quantitative comparison between a given quantity and quantity of the same kind chosen as a unit

4 What is a ‘ Measuring Instrument ‘ Instruments which are used to measure the quantities are known as ‘Measuring Instruments’

5 Name some of the Electrical Measuring Instruments and what they measure? Voltmeter measures voltage Ammeter measures current Wattmeter measures power Energy meter measures energy Known to unknown

6 Give Some examples of non-electrical quantities to be measured are Temperature Pressure Force Displacement Stress Strain etc Known to unknown

7 Measurement of non electrical quantities Two options (either) To measure directly with non electrical instruments Ex: Temperature with thermometer (or) To measure with electrical instrument by converting the non electrical quantity into an electrical quantity Ex: speed with tachometer

8 Measurement of non electrical quantities The measured electrical quantity is proportional to the original non electrical quantity Hence The scale of the electrical instrument can be calibrated directly to give the value of the non electrical quantity

9 Measurement of non electrical quantities The second option (i.e., conversion into electrical signal and then measuring it) is preferred because This process is Accurate Reliable Repeatable and also Useful for further process

10 A device known as transducer is used to convert non electrical quantity into electrical quantity Conversion of physical stimuli to be measured into electrical signal

11 Transducer - a Latin word - means ‘ To Convert’

12 Definition of a transducer A device that receives energy from a system and transmits it to another system in the same form or in another form

13 Do you know how the transducers look like ? Transducer

14 Transducers

15 TRANSDUCERS

16 A Generalized measuring instrument consists of three major elements 1.Input device 2.Signal processing device 3.Output device Generalized Measuring Instrument

17 Generalized Measuring Instrument Input device Signal processing device Output Device measured Output device is Indicating instrument / oscilloscope / visual display

18 Block diagram of transducer Sensing element Transduction element Sensor response Electrical signal Non electrical quantity Sensing element: Responds to change in a physical condition Transduction element: Transforms the output of sensing element to electrical output

19 The various input signals are voltage, current, resistance,power inductance, capacitance, frequency, phase angle, flux, flux density displacement,velocity, pressure, temperature and so on Input signals

20 Applications of transducers Automotive Aerospace Military Pharmaceutical Chemical Food preparation industries Transducers find applications in numerous fields

21 Leak detection Energy management, Material durability testing, Batch weighing, Closed loop servo system, Weighed moon rock, Thickness of (unbroken ) egg shell, The firmness of onions, The rate of fruit growth Applications cont..

22 Automatic performance testing of pumps Air conditioners Bicycle brakes Jet engines refrigerators helicopter blades Missile gyros Applications cont..

23 Strains Stresses Peak torques Remote tank levels Fuel flow Mass flow Tool character Spring force Wheel run out Oven temperature Center of gravity Carpet backing …..to name just a few Applications cont..

24 Applications of transducers Type of transducer Application Force and Load measure tension, compression, and shear forces Strain gauges convert force, pressure, tension, etc., Into an electrical signal Torque Sensors Measure torque Vibration Sensors measure vibration and acceleration Piezoelectric Sensors measure the electrical potential caused by applying mechanical force to a piezoelectric material.

25 Types of transducers and its applications Sl. No Electrical parameter and class of transducer Applications 1Resistance (a) Potentiometer device pressure, displacement (b) Hot wire meter gas flow, gas pressure © Resistance thermometer Temperature, radiant heat (d) ThermistorTemperature (f) Photo conductive cellphotosensitive relay

26 Sl. No Electrical parameter and class of transducer Applications 2capacitance (a) variable capacitance pressure gauge pressure, displacement (b) capacitance microphone speech, music, noise ©dielectric gauge liquid level, thickness Types of transducers and its applications

27 Sl. No ELECTRICAL PARAMETER AND CLASS OF TRANSDUCER APPLICATIONS 3inductance (a) Magnetic circuit transducerpressure, displacement (b) Reluctance pick-up pressure, displacement, vibration ©Differential transformer pressure force, displacement, position (d) eddy current gaugedisplacement, thickness (e) Magnetostriction gaugeforce, pressure Types of transducers and its applications

28 Sl. No ELECTRICAL PARAMETER AND CLASS OF TRANSDUCER APPLICATIONS 4voltage and current (a) hall effect pick-up magnetic flux, current, power (b) Ionization chamber particle counting radiation ©photo emissive celllight and radiation (d) Photo multiplier tube light and radiation, photosensitive relays Types of transducers and its applications

29 Sl. No ELECTRICAL PARAMETER AND CLASS OF TRANSDUCER APPLICATIONS 5 active transducers (a) Thermocouple and thermopile temperature, heat flow and radiation (b) Moving coil generator velocity, vibration © Piezoelectric pick-up light and radiation (d) Photovoltaic light meter, solar cell Types of transducers and its applications

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