### Preface

This Textbook is intended for all trainees in the field of
electrotechnology. It contains the more important circuit diagrams and formulas
and a limited number of selected tables of direct-current and
alternating-current engineering.

With the help of this Textbook, the trainee will be in a
position to read and interpret electrical wiring and circuit diagrams in order
to perform his job according to the rules of good workmanship. At the same time,
the trainee is encouraged to prepare and draw circuit diagrams without
assistance and to use graphical symbols
correctly.