Transducer PPT..ppt
- 1. Department of Electrical Engineering Presentation Topic :- Transducer By Aniket Gunjal Guided By :- Prof. Tushar Wadgule
- 2. Content • Introduction • Classification • Types (Resistive, Inductive & Capacitive) • Basic Requirements
- 3. Transducer Pressure transducer Stain gauge transducer Piezoelectric transducer LVDT transducer Capacitive transducer
- 4. Introduction • A transducer is a device which transforms a non-electrical (physical quantity) into an electrical signal. • Electrical and Mechanical transducer are the major types of the transducer. Transducer Non-electrical physical quantity (tempraturre, pressure, sound, light, etc.) Electrical signal (voltage, current, etc.)
- 5. CONSTRUCTION • It consist two parts i.e. sensing element and transduction element. • Sensing/Detecting element :- device which produce measurable response to change in physical quantity. • Transduction :- convert sensor output to suitable electrical form.
- 6. Working Principle • When non-electrical physical quantity is present at the i/p of the transducer, converts it into electrical signal with the help of sensing & transduction element.
- 7. • Electrical Transducer :- a device capable of converting physical quantities into a proportional electrical quantity such as voltage or electric current. Fig. Thermocouple
- 8. Fig. Burdon Tube • Mechanical Transducer :- Transducer that respond to change in the physical condition of system and gives output in other form. (output is mechanical in nature like motion..) Fig. Air Pressure Gauge
- 9. Classification • Active and Passive Transducer • Primary and Secondary Transducer • Analog to Digital Transducer • Transducer and Inverse Transducer
- 10. Active & Passive Transducer Active transducer :- • They do not require an external power. (called active transducer) • Produce an analog voltage or current when stimulated by some physical form of energy. • It is also called as Self-Generating transducer. • Ex. Thermocouple, magnetic coil & photovoltaic cell transducer.
- 11. Passive Transducer : • Transducers which require an external power source for their operation is called a passive transducer. • Ex. LVDT (used as an inductive transducer , converts motion into an electrical signal) • Also called “External Powered Transducer”.
- 12. Primary & Secondary Transducer • Primary :- A transducer which is directly connected to input called primary transducer. • Secondary :- A transducer which is not directly connected to input called secondary transducer.
- 13. Analog & Digital Transducer • Analog :- Transducers which covert input quantity into an analog output which is a continuous function of time. • Ex. Strain gauge, LVDT, thermocouple. • Digital :- Transducers which convert input quantity into an electrical output in the form of pulses and its output is represented by 0 & 1. • Ex. Encoder, Digital resolvers, Digital tachometers, Hall effect sensors, Limit switch.
- 14. • Inverse Transducers :- • Transducer which converts electrical quantity into non- electrical physical quantity. • Widely used in feedback measuring system. • Ex. Current carrying coil moving in a magnetic field, piezoelectric crystal.
- 15. Types • Resistive transducer • Inductive transducer • Capacitive transducer
- 16. Resistive Transducer • In these transducers, the resistance changes due to the some physical phenomenon. R = ρ L/ A • Where, R = resistance of conductor in Ω ρ = resistivity of conductor material Ω-m L = length of conductor in m A = area of conductor in meter square • Ex. Potentiometer, Strain gauge, Thermistors & Resistance thermometer.
- 17. Fig. Sliding contact device R = ρ L/ A i.e. L ∝ R A transducer like potentiometer works on sliding contact principle.
- 18. Inductive Transducer • A transducer that works on the principle of electromagnetic induction or transduction mechanism is called an inductive transducer. • Working principle uses :- Self Inductance , Mutual Inductance & Eddy Current Production. • Ex. Variable inductance transducer, Variable reluctance inductive transducer, etc
- 19. Capacitive Transducer • The value of capacitance changes due to change in input quantity that is to be measured. • Comprises of two parallel metal plates, separated by air or vacuum. • Ex. Variable capacitance pressure gauge, Capacitor microphone & Dielectric gauge.
- 20. Basic Requirements Of Transducers • Ruggedness :- Capable of withstanding overload and provide safety. (i.e overload protection) • Linearity :- Input-output characteristics should be linear and produce characteristics in symmetrical way. • Repeatability :- It should reproduce same output signals. • High output signal quality :- Quality of output signal should be good.
- 21. • High Reliability and Stability :- It should give minimum error in measurement. • Good Dynamic Response :- Output should faithful to input with time.