Electrical Impedance Principles, Measurement, and Applications By Luca Callegaro

Electrical Impedance Principles, Measurement, and Applications By Luca Callegaro

Contents:

Chapter 1 Basics

Chapter 2 Impedance definitions

Chapter 3  Devices and appliances of interest in impedance measurement

Chapter 4 Common practice methods

Chapter 5 Going digital

Chapter 6 Some applications of impedance measurement

Chapter 7 Metrology: traceability and uncertainty

Chapter 8 Metrology: standards

Chapter 9 Metrology: realization and reproduction

Preface:

Motivation The interest in the accurate measurement of electrical impedance is shared by scientists and engineers from different back grounds. Impedance measurements can be performed on an impedance standard, to perform a calibration and issue a calibration certificate. Elec tromechanical appliances and electronic components can be characterized by impedance measurement to identify the parameters of their equivalent electrical model. Properties such as resistivity, permittivity, and permeability of material samples can be derived from impedance measurements conducted with proper electrical fixtures. Biological quantities related to atissue, or even to a living being, can be related to their impedance. Sensors of many physical quantities can have electrical impedance as their output. Impedance spectroscopy permits to follow the evolution of an ongoing electrochemical reaction; impedance tomography is an imaging technique. Despite such broad range of existing applications, and the potential for new ones, high school and university courses show a marginal interest to the subject of impedance measurement. Often, impedance measurement techniques are described as minor variations of the corresponding dc resistance measurements; recent publicationsmay cite obsolete measurement techniques. Difficulties When performing an impedance measurement, the experimenter faces conceptual and practical difficulties that are not encountered inresistance measurements. Voltages and currents become geometry-dependent quantities, and different parts of the measurement circuit can interact in unexpected ways because of mutual capacitances and inductances. Even commercial impedance meters ask for careful wiring techniques, which may involve a number of conductors. The measurement result can be ex pressed in a variety of representations, related by non-trivial mathematical transformations, prone to be misinterpreted.