Pressure sensor definition,history,types..

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1. Pressure sensor

2. Agenda Definition History Types of Pressure Sensor Applications

3. Definition Pressure sensor is a electronic device senses or monitorize the pressure in input(gases or liquids) and converts the data into an electronic signal

4. History: Galileo Galilee have been trying to measure pressure,for next three hundred years scientists would make discoveries of pressure measurement. 1930-Roy Carlson- first unbonded wire Strain gauge to measure strain inside a concrete structure 1954- Capacitive pressure transducer-Carl spausing. This sensor provide a way to measure very small pressure with sufficient accuracy 1960-The first thin film transducer with good stability and Low hysteresis Were developed,this technology remains today for high pressure measurement 1973-William Polye-Capacitive tranducer using quartz For low pressure ranges

5. Types of pressure sensor Strain gauge pressure sensor Piezoelectric pressure sensor Capacitive pressure sensor Manometer pressure sensor Vacuum pressure sensor Bourdon tube Aneroid Barometer

6. Strain Gauge Uses a metalwork or semiconductor to Measure in changes in pressure Commonly used in Wheatstone bridge Change in Measured voltage Merits: small in size stable device with Fast response Good over-range capability Demerits: unstable due to bonding material sensitive temperature

7. Piezoelectric sensor When pressure is applied to crystal they are elasticated deformed.It involves the measurement of such deformation. Quartz commonly used as a sensing crystal as it is inexpensive stable and insensitive to temperature variation Merits : very high pressure Measurement self generated signal Demerits : Dynamic sensing only Temperature sensitive

8. Capacitance This sensor is energized Electrically with high frequency oscillation. Accurate pressure measurement and wide operating range Commonly used in determining the level in vessel and tank Merits: inaccuracy 0.01-0.2% Linearity Demerits: limited over pressure capability vibration

9. Manometers Good example for pressure measuring instrument ‘U tube manometers’ consists of U shaped glass tube Partially filled with a liquid When there are equal pressure on both sides,the liquid level will corresponds to zero Point on scale

10. C Bourdon tube It works on simple principle that a bend tube will change it shape When exposed to variation in internal and external pressure. Pressure applied internally,Tube straightains and Returns it original form,when pressure is released Merits: Inexpensive,good sensitivity wide operating range Demerits: non linear transducer limited life when subject to Shock and vibration

11. Applications: Sensing printer ink levels Air flow rate in equipment Computer cooling systems Semiconductor Process equipment Laser measurement As well as clean room monitoring devices

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