4. Structure, function and symbols of electrical components and devices
In order to be able to understand electrotechnical drawings and diagrams, generally accepted graphical symbols, test marks and circuit symbols are being used. All those symbols are defined in corresponding so called "DIN-standards" (DIN = German Institute for Standardisation). In this context, especially DIN 40900 (electrical engineering symbols) and DIN 19227 (symbols of measuring, control and regulation installations) are important.
The following table shows a selection of the most frequently used symbols.