Ceramic Sensors

Technology and Applications

Toshko Nenov, Stefcho P. Yordanov

• Publisher: CRC Press
• Year: 2020
• Topic: Technology & Engineering
• eBook ISBN:
  9781000160024
• Subtopic: Electrical Engineering & Telecommunications
• Index: Technology & Engineering

From the Author's Preface Ceramic sensors have been in use for more than thirty years. Since ceramics exhibit a number of specific characteristics that enable their cost to become lower and their reliability to increase, they have occupied a significant position in sensor technology. This is why many companies and universities have directed their efforts towards investigating and developing new ceramic sensors and expanding their areas of application. To the best of our knowledge.., there [has been] no book treating different sensors on the basis of their common physical and chemical properties, technological principles, and applications. This book [is] a detailed survey of ceramic sensors and a generalization of the results achieved in this field so far. Ceramic sensors for different physical quantities are discussed without going too deep into theory... The concept of ceramic sensors includes all sensors that are produced using ceramic technology. It also covers thick film sensors, since from a structural and technological point of view, they can be regarded as a variety of ceramic sensors. The subject of scientific research in this book is humidity, gas. temperature, and pressure sensors on the basis of semiconductor and dielectric ceramic materials and solid electrolytes. Special attention is paid to the physical and chemical, as well as the technological, bases of ceramic sensors, their classification, the types of materials used... , the methods of controlling their parameters and characteristics, the areas of application, and the electric circuits for connecting the sensors.

CHAPTER 1

Definitions and Classifications of Sensors

1.1 SENSORS

The progress made in information processing techniques and the rapid development of microprocessors and computer technologies necessitate corresponding advances in the development of sensors. Microprocessors are incorporated extensively into measuring and control systems. As the possibilities of such systems increase, the role of sensors, acting as the primary units in information perception, rises considerably, and demand for them grows. Sensors become important factors in automation and robot technology, and gain an increasingly greater significance as structural elements of systems.

Most generally speaking, sensors are devices which convert physical or chemical quantities into electrical signals convenient to use. According to the International Electrotechnical Committee (IEC), “The sensor is the primary part of a measuring chain which converts the input variable into a signal suitable for measurement” [1]. According to Göpel et al. [2], “A sensor is a sensor element with housing and electrical connections included” and “a sensor system is a sensor which incorporates some kind of signal processing (analog or digital).” The sensor is included in the sensor system and it is the first element to input the information measured.

The generalized block diagram of a sensor system is presented in Figure 1.1. The signal entering the sensor is small in amplitude, being mixed with interfering signals and noises. It may be necessary to linearize the signal. The shaping of the signal with optimal characteristics for subsequent processing is carried out by means of amplifiers, filters, and other analog circuits. In some cases part of these circuits are in the immediate proximity of the sensor element. The shaped signal is then converted into a digital one and is transmitted to the microprocessor.

FIGURE 1.1. Block diagram of a sensor system.

German and Russian authors treat the sensor as a composition of a sensor element which is directly influenced by the quantity being measured and an electronic circuit for preliminary processing of the signal. In this way the sensor also incorporates part of the signal shaper.

The characteristics of the sensor system are greatly determined by the sensor. It converts one form of energy into another. There are two basic types of sensors: active and passive. The active sensor converts one form of energy directly into another without the need for an external source of energy or excitation [Figure 1.2(a)].

The passive sensor cannot convert energy directly, but it controls the energy or the excitation entering from another source.

The sensor carries out a quantitative conversion of a certain property of the substance or the process. The substance may be a solid, a liquid or a gas and its state may be static or dynamic (i.e., a process). The property which is registered quantitatively may be detected in a number of ways and it may have a physical (e.g., mechanical, thermal, electromagnetic, etc.) nat...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• Preface
• Acknowledgements
• Introduction
• Chapter 1. Definitions and Classifications of Sensors
• Chapter 2. Physical-Chemical and Technological Principles of Ceramic Sensors
• Chapter 3. Ceramic Humidity Sensors
• Chapter 4. Ceramic Gas Sensors
• Chapter 5. Ceramic Temperature Sensors
• Chapter 6. Ceramic Pressure Sensors
• Chapter 7. Multifunctional Ceramic Sensors
• Chapter 8. Application of Ceramic Sensors
• References
• Index
• About the Author