Physics SERIES IN SENSORS SERIES IN SENSORS SERIES EDITORS: BARRY E. JONES AND HAIYING HUANG Du Resistive, Capacitive, Inductive, Resistive, Capacitive, R and Magnetic Sensor Technologies e s is Inductive, and t i v Sensor technologies have experienced dramatic growth in recent years, e , making a significant impact on national security, health care, environmental C Magnetic Sensor improvement, energy management, food safety, construction monitoring, a p manufacturing and process control, and more. However, education on sensor a c Technologies technologies has not kept pace with this rapid development…until now. i t i v Resistive, Capacitive, Inductive, and Magnetic Sensor Technologies examines e , existing, new, and novel sensor technologies and—through real-world examples, I n sample problems, and practical exercises—illustrates how the related science and d engineering principles can be applied across multiple disciplines, offering greater u c insight into various sensors’ operating mechanisms and practical functions. The t i book assists readers in understanding resistive, capacitive, inductive, and magnetic v e (RCIM) sensors, as well as sensors with similar design concepts, characteristics, , a and circuitry. n d Resistive, Capacitive, Inductive, and Magnetic Sensor Technologies is a M complete and comprehensive overview of RCIM sensing technologies. It takes a g a unique approach in describing a broad range of sensing technologies and n e their diverse applications by first reviewing the necessary physics, and then t i explaining the sensors’ intrinsic mechanisms, distinctive designs, materials c and manufacturing methods, associated noise types, signal conditioning S e circuitry, and practical applications. The text not only covers silicon and n s metallic sensors but also those made of modern and specialized materials o r such as ceramics, polymers, and organic substances. It provides cutting- T edge information useful to students, researchers, scientists, and practicing e c professionals involved in the design and application of sensor-based products h n in fields such as biomedical engineering, mechatronics, robotics, aerospace, o and beyond. l o g i Winncy Y. Du e s Cover image: an integrated Hall sensor device, courtesy of SENTRON AG, a Melexis Company, Switzerland K10628 ISBN 978-1-4398-1244-0 90000 9 781439 812440 K10628_COVER_final.indd 1 9/19/14 11:52 AM Resistive, Capacitive, Inductive, and Magnetic Sensor Technologies Resistive, Capacitive, Inductive, and Magnetic Sensor Technologies Winncy Y. Du San Jose State University CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2015 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Version Date: 20140919 International Standard Book Number-13: 978-1-4398-1249-5 (eBook - PDF) This book contains information obtained from authentic and highly regarded sources. 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Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com To my late parents: Xianmin Du (杜贤民) and Shujie Chao (曹淑杰) who not only gave me life, but also taught me how to live; To my dear brothers: Chengzhi Du (杜承志) and Yingzhi Du (杜英志) who never ask me for anything, but always give me everything; To my beloved husband: Scott Yelich who enriches my life and multiplies my efforts. Contents Preface....................................................................................................................xvii Acknowledgments ...................................................................................................xix Author .....................................................................................................................xxi Chapter 1 RCIM Sensor Characteristics and Terminology ..................................1 1.1 RCIM Sensor History ................................................................1 1.2 RCIM Sensor Definition ............................................................2 1.3 RCIM Sensor Characteristics and Terminology .......................2 1.3.1 Transfer Function .........................................................2 1.3.2 Sensitivity .....................................................................2 1.3.3 Offset ............................................................................5 1.3.4 Full Span and Full-Span Output ..................................5 1.3.5 Accuracy .......................................................................7 1.3.6 Hysteresis .....................................................................8 1.3.7 Nonlinearity .................................................................9 1.3.8 Noise and Signal-to-Noise Ratio ..................................9 1.3.9 Resolution ...................................................................11 1.3.10 Precision and Repeatability Error ..............................12 1.3.11 Calibration and Calibration Error ..............................14 1.3.12 Response Time and Bandwidth ..................................16 1.3.13 Sensor Lifespan ..........................................................18 1.3.14 Other Sensor Characteristics ......................................20 Exercises .............................................................................................21 References ..........................................................................................24 Chapter 2 Resistive Sensors ................................................................................25 2.1 Introduction .............................................................................25 2.2 Potentiometric Sensors ............................................................25 2.2.1 Sensing Principle ........................................................25 2.2.2 Configuration and Circuitry .......................................26 2.2.3 Potentiometric Sensor Design ....................................29 2.2.3.1 Linear Potentiometers .................................29 2.2.3.2 Rotary Potentiometers ................................30 2.2.4 Potentiometric Sensor Applications ...........................30 2.2.4.1 Potentiometric Pressure Sensors .................30 2.2.4.2 Potentiometric Airflow Sensor ...................31 2.2.4.3 Potentiometric Gas Sensor ..........................31 2.2.4.4 Potentiometric Biosensor ............................32 vii viii Contents 2.3 Resistive Temperature Sensors ................................................33 2.3.1 Thermoresistive Effects ..............................................33 2.3.1.1 Thermoresistive Effect for Metals ..............33 2.3.1.2 Thermoresistive Effect for Semiconductors .........................................37 2.3.2 Wiedemann–Franz Law for Metals ...........................39 2.3.3 Resistance Temperature Devices (RTDs) ...................40 2.3.3.1 RTD Characteristics ...................................40 2.3.3.2 RTD Measurement ......................................41 2.3.3.3 RTD Design ................................................42 2.3.3.4 RTD Applications .......................................43 2.3.4 Thermistors ................................................................44 2.3.4.1 Thermistor Characteristics .........................44 2.3.4.2 Thermistor Design ......................................46 2.3.4.3 Thermistor Applications .............................48 2.4 Photoresistive Sensors .............................................................49 2.4.1 Photoresistive Effect ...................................................49 2.4.2 Photoresistor Characteristics ......................................54 2.4.3 Photoresistive Sensor Design .....................................56 2.4.4 Photoresistive Sensor Applications ............................57 2.5 Piezoresistive Sensors ..............................................................58 2.5.1 Piezoresistive Effect in Metals and Alloys .................58 2.5.2 Piezoresistive Effect in Semiconductors ....................60 2.5.3 Characteristics of Piezoresistive Sensors ...................63 2.5.4 Piezoresistive Sensor Design ......................................67 2.5.4.1 Types and Structures of Strain Gauges.......67 2.5.4.2 Strain Gauge Materials ...............................70 2.5.4.3 Supporting Structure and Bonding Methods of Strain Gauges ..........................71 2.5.5 Piezoresistive Sensor Applications .............................74 2.5.5.1 Piezoresistive Accelerometers ....................74 2.5.5.2 Piezoresistive Pressure Sensor ....................75 2.5.5.3 Piezoresistive Flow Rate Sensor .................75 2.5.5.4 Piezoresistive Blood Pressure Sensor .........76 2.5.5.5 Piezoresistive Force Sensor ........................76 2.5.5.6 Piezoresistive Imaging Sensor ....................76 2.6 Chemoresistive Sensors ...........................................................77 2.6.1 Chemoresistive Effect ................................................77 2.6.2 Characteristics of Chemoresistive Sensors ................79 2.6.2.1 Characteristics of Mixed Metal Oxide Semiconductor Sensors ...............................79 2.6.2.2 Characteristics of Polymer or Organic Material Sensors .........................................80 2.6.3 Chemoresistive Sensor Design ...................................81 2.6.4 Chemoresistive Sensor Applications ..........................84 2.6.4.1 Hygristor .....................................................84