Circuit breakers, relays, terminals, microphones, current collectors and
commutators, all operate with electric contacts. Industry is making
extensive use of contacts with ever-increasing demands on efficiency.
The need of up to date reliable theories as well as of formulas and
tables for applications is becoming pressing. This book is an attempt to
meet this need. As is the case in many other branches of technology
today, problems which arise in the field" of electric contacts involve
insight in various other disciplines of physics, including parts which
have not yet developed to such an extent that they. are treated in
elementary text books. Con- sidering the lack of introductions to some
topics of this kind it is felt that orienting chapters, for instance, on
the tunnel effect, the theory of the arc, the structure of carbon, and
the band theory of electric conduction in solids might be valuable for
many readers. In order not to burden the main text with such chapters
they have been presented as appendices. Several chapters have been
devoted to the theory offriction and wear.