1st Edition

Introduction to Sensors for Electrical and Mechanical Engineers

By Martin Novák Copyright 2021
    328 Pages 331 B/W Illustrations
    by CRC Press

    328 Pages 331 B/W Illustrations
    by CRC Press

    Sensors are all around us. They are in phones, cars, planes, trains, robots, mils, lathes, packaging lines, chemical plants, power plants, etc. Modern technology could not exist without sensors. The sensors measure what we need to know and the control system then performs the desired actions. When an engineer builds any machine he or she needs to have basic understanding about sensors. Correct sensors need to be selected for the design right from the start. The designer needs to think about the ranges, required accuracy, sensor cost, wiring, correct installation and placement etc. Without the basic knowledge of sensors fundamental no machine can be built successfully today.

    The objective of this book is to provide the basic knowledge to electrical and mechanical engineers, engineering students and hobbyist from the field of sensors to help them with the selection of “proper” sensors for their designs. No background knowledge in electrical engineering is required, all the necessary basics are provided. The book explains how a sensor works, in what ranges it can be used, with what accuracy etc. It also provides examples of industrial application for selected sensors.

    The book covers all the major variables in mechanical engineering such as temperature, force, torque, pressure, humidity, position, speed, acceleration etc.

    The approach is always as follows:

    - Explain how the sensor works, what is the principle

    - Explain in what ranges and with what accuracy it can work

    - Describe its properties with charts, eventually equations

    - Give examples of such sensors including application examples

    1 Measurement basics
    1.1 General properties
    1.2 Static properties
    1.3 Dynamic properties
    1.4 Uncertainty of measurement

    2 Circuits for sensors
    2.1 Voltage signal
    2.2 Current signal
    2.3 Bridge circuits
    2.4 Difference amplifier
    2.5 Instrumentation Amplifier

    3 Temperature - contact
    3.1 Resistive temperature detectors (RTD)
    3.2 Thermistors
    3.3 Circuits for RTD´s
    3.4 Thermocouples
    3.5 Temperature sensor placement

    4 Temperature - non contact
    4.1 Absorption in atmosphere and in materials
    4.2 Materials for IR optics
    4.3 Monochromatic pyrometers
    4.4 Total radiation pyrometers
    4.5 IR thermometers
    4.6 Principles of correct use of IR thermometers

    5 Force
    5.1 Metallic strain gauges
    5.2 Semiconductor strain gauges
    5.3 Circuits for strain gauges
    5.4 Strain gauge placement
    5.5 Load cells and example applications

    6 Torque
    6.1 Torque dynamometer
    6.2 Electronic torque sensors

    7 Position
    7.1 Resistive sensor
    7.2 Inductive sensors
    7.3 Capacitive sensors
    7.4 Magnetic (Hall) sensors
    7.5 Optical sensors
    7.6 Incremental rotary encoders (IRC)
    7.7 Absolute rotary encoders
    7.8 Microwave position sensor (radar)
    7.9 Interferometers
    7.10 Proximity sensors

    8 Speed and RPM
    8.1 Electromagnetic - tachodynamo
    8.2 Optoelectronic speed sensor
    8.3 Inductive speed sensor
    8.4 Hall speed sensor
    8.5 Stroboscope

    9 Acceleration
    9.1 Piezoelectric acceleration sensor
    9.2 Piezoresistive acceleration sensor
    9.3 Acceleration sensors with measured displacement - general principle
    9.4 Capacitive accelerometer
    9.5 Optical accelerometer

    10 Pressure
    10.1 Calibration pressure gauges
    10.2 Deformation manometers
    10.3 Bolometric vacuum meter - PIRANI
    10.4 Ionization pressure sensor
    10.5 Placement of pressure sensors

    11 Humidity
    11.1 Dew-point hygrometer
    11.2 Psychrometer
    11.3 Hygrometer with dry electrolyte

    12 Flow
    12.1 Restriction flow meters
    12.2 Rotameter
    12.3 Turbine flowmeter
    12.4 Wire anemometer
    12.5 Ultrasonic flowmeter
    12.6 Electromagnetic flowmeter
    12.7 Coriolis flowmeter

    13 Liquid level
    13.1 Visual liquid level meter
    13.2 Float
    13.3 Hydro-static sensor
    13.4 Bubbler
    13.5 Electrical conductivity level sensor
    13.6 Thermal conductivity level sensor
    13.7 Radioisotope liquid level meter
    13.8 Capacitive liquid level sensing
    13.9 Ultrasonic liquid level meter
    13.10 Radar liquid level meter
    13.11 Vibrating level switches

    14 Example labs
    14.1 Temperature-contact - thermocouples
    14.2 Temperature- non-contact - emissivity
    14.3 Position - LVDT
    14.3.1 Introduction
    14.4 Position - proximity sensors - influence of material
    14.5 Position - linear displacement sensors

    References
    Other recommended literature
    Appendix
    A Pt100, DIN/EN/IEC 60751, α = 0.00385
    B Pt100, α = 0.00392
    C Pt500
    D Pt1000
    E Ni120
    F Cu10
    G Thermocouple type J
    H Thermocouple type K
    I Thermocouple type T
    J Thermocouple type E
    K Thermocouple type R
    L Thermocouple type S
    M Material emissivity tables
    Index

    Biography

    Martin Novák presently works as a Professor at the Czech Technical University in Prague.