Measuring Current Voltage and Power Handbook of Sensors and Actuators Vol 7

233 Pages·1999·8.06 MB·English

by  K. Iwansson

Measuring Current,
Voltage and Power
HANDBOOK OF SENSORS AND ACTUATORS
Series Editor: S. Middelhoek, Delft University of Technology,
The Netherlands
"\-..i ~'"
Volume 1 Thick Film Sensors (edited by M. Prudenziati)
Volume 2 Solid State Magnetic Sensors (by C.S. Roumenin)
Volume 3 Intelligent Sensors (edited by FI. Yamasaki)
Volume 4 Semiconductor Sensors in Physico-Chemical
Studies (edited by L. Yu. Kupriyanov)
Volume 5 Mercury Cadmium Telluride Imagers
(by A. Onshage)
Volume 6 Micro Mechanical Systems (edited by T. Fukucia
and W. Menz)
Volume 7 Measuring Current, Voltage and Power
(by K. Iwansson, G. Sinapius and W. Hoornaert)
HANDBOOK OF SENSORS AND ACTUATORS 7
. . . . . . . . .
Measuring Current,
Voltage and Power
Kaj Iwansson
European Patent Office
Rijswijk, The Netherlands
GiJnther Sinapius
Europfiisches Patentamt
MOnchen, Germany
Winfried Hoornaert
European Patent Office
Rijswijk, The Netherlands
1999
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First edition 1999
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The need for a
Handbook of Sensors and Actuators series
The arrival of integrated circuits, like microprocessors and memories with extremely good
performance/price ratios has had a profound influence on many areas of technical encleavour.
In the measurement and control field, modern electronic circuits have been introduced on a
large scale leading to very sophisticated systems and novel solutions. However, in these
measurements and control systems, sensors and actuators are frequently applied that were
conceived many decades ago. Consequently, it has become necessary to improve these devices
in such a way that their performance/price ratios would be in more agreement with that of
modern electronic circuits.
The demand for these new devices initiated worldwide research and development programs
in the field of sensors and actuators. Many generic sensor technologies have been examined,
from which the thin- and thick-film, glass fibre, metal oxides, polymers, quartz and silicon
technologies are the most important.
A growing number of publications on this topic started to appear in a wide variety of scientific
journals until, in 1981, Elsevier Science started the publication of the scientific journal Sensors
and Actuators. It has since become one of the leading journals in this field, publishing papers
on sensors and actuators made in various technologies.
When the development of a scientific field expands, the need for handbooks arises, wherein
the information that appeared earlier in journals and conference proceedings is systematically
and selectively presented. The sensors and actuators field is now in this position. For this reason,
Elsevier Science took the initiative to develop a series called
Handbook of Sensors and Actuators
which contains the most meaningful background material that is important for the sensors
and actuators field. Titles on thick film sensors, magnetic sensors, intelligent sensors, semi-
conductor sensors, mercury cadmium telluride imagers and micro mechanical systems have
been published. Coverage of subjects such as pressure sensors, radiation sensors, microsystems
technology, piezoelectric sensors, robot sensors and accelerometers will soon follow.
The series comprises one- and multi-author handbooks. Great care is given to the selection of
the authors and editors. They are all well-known scientists in the field of sensors and actuators
and have impressive international reputations.
Elsevier Science and I, as editor of the series, are delighted that these handbooks have already
received such a positive response from the sensors and actuators community. We hope that
the series will be of great use to many scientists and engineers working in this exciting field.
Simon Middelhoek
Handbook of Sensors and Actuators
Series Editor
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vii
SUMMARY
This authoritative new book focuses on recent developments in the instrumentation for
sensing voltages and currents. It covers new trends and challenges in the field, such as
measurements of biocurrents, the increased speed of the components for data taking,
testing of computers and integrated circuits where the measurement of rapid voltage and
current variations on a very small geometrical scale is necessary. The first chapter
concentrates on recent methods to sense voltages and currents, while the rest of the book
investigates tL.z applied side, covering for instance electrical power and energy
measurements. The main purpose of this volume is to illustrate commonly employed
techniques rather than track the scientific evolution and merits and therefore mainly
covers patent literature aimed at industrial applications. It is an exciting addition,
justifying the series' claim to cover state-of-the-art developments in both the applied and
theoretical fields of sensors and actuators.
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Preface
The measurement of voltages and currents is a common task in the field of electricity and electronics.
From a technical point of view it is useful to identify schematically different steps of such a measure-
ment. In a first step a voltage or a current is sensed, intermediate steps such as amplification, transmis-
sion and further treatment may follow to yield the result in the final step. Today in most cases micro-
processors perform the final steps of such measurements. Analog-to digital converters digitise a volt-
age that is proportional to the value to be measured and a processor performs further computations and
handles the storage and the display of the results. The prerequisite for such measurements are sensors
or transducers that respond in a known way to the voltage or current to be measured. The emphasis of
this book is put on recent developments of the instrumentation for sensing voltages and currents.
Aside from the general trend towards smaller, cheaper and more reliable instrumentation, new de-
mands have arisen. New applications, like measurements of biocurrents, ask for higher sensitivities.
Computers and integrated circuits pose new challenges. To exploit the increased speed of the compo-
nents for data taking, suitable sensors are required. The accuracy that can be achieved depends more
than ever on the first step, the acquisition of the raw data. The influence of the measurement process
on the results becomes more crucial. Testing of integrated circuits themselves is a completely new
application. For such tests one has to measure rapid voltage and current variations on very small
geometrical scales. Here, as well as in the traditional high voltage applications, contactless measure-
ments play an important role.
The organisation of this book is as follows: In the first chapter different methods to sense voltages and
currents are described. For the sake of completeness most commonly used methods are mentioned, we
concentrate, however, on those developed recently. The following chapters address the subject from
the side of different applications in which voltages and currents are sensed.
This publication mainly covers patent literature ~. The reason for the emphasis on patent literature is,
aside from our professional bias as patent examiners at the EPO, that patents, as opposed to scientific
publications, are aimed at industrial application, i.e. at instruments that can be built. Since the main
purpose of this publication is to illustrate commonly employed techniques rather than to track the
scientific evolution and merits in particular fields, in general those publications that illustrate a par-
ticular measurement principle best have been cited. The citation of a particular reference does there-
fore not imply that this is the first or most pertinent publication in the respective field.
We want to dedicate this book to the late Dieter Kuschbert, a very friendly, generous and competent
person in whose directorate in the DG 1 of the EPO in The Hague the project of this text evolved, and
to our families who patiently let us spend many evenings and weekends on the project.
Finally, we would like to thank our employer, the European Patent Office for giving us support and
time, and Myriam Torbitzky, who did the desktop publishing part with great dedication.
The Hague and Munich
August 1998
~Except for the US ntunbers, which refer to published patents, most of the other patent publication numbers refer
to patent applications, which may differ from the granted patents.