How to Read a German Schematic
If you've been given an electrical schematic that uses the German symbols rather than the U.S. ones, you'll need to learn to read a German schematic. Schematic symbols are used to represent electrical components in schematic diagrams. Understanding the meanings of these symbols is very important if you are constructing an electrical circuit, and the symbols differ across the world. The German schematic symbols are relatively similar to the British or international symbols, but many differ strikingly from the American symbols. Learn some differences in important symbols to learn how to read a German schematic.
Notice that some symbols are no different from the American symbols. The symbols used to show conductors (wire), ground points and resistors are exactly the same in German schematics. In addition, the symbol for a meter (a circle with the function code written in the center) is also virtually the same. Scan your schematic for any of these recognizable symbols.
Look over your schematic for German capacitor symbols. These can be recognized by two straight, parallel lines that aren't connected in the center. The wire will run from the outer edges of each line, but there is nothing in the center of them. The American capacitor symbol is basically the same, except that one of the lines is curved. Coils are displayed as a box instead of a circle on German schematic diagrams.
Recognize the similarities between German contact symbols and American ones. Common American contact symbols have two circles with a line between them. If the contact is usually open, the line doesn't link the circles; if it is usually closed, it does. Notice that the German symbol for usually open contacts is the same, aside from having no circles, and the normally closed contact symbol is joined by a perpendicular line from the opposite wire. Time-delay contacts are shown with a horizontal dotted line with an arc going through it.
Notice the similarities between the German and American fuse symbols. The American symbol is a rectangle with two lines at the ends running parallel to the short edges. The German symbol is simply a rectangle with a wire line running through it, parallel with the longer edges. Identify motor symbols by looking for the standard American symbols with an "M" and a "1" or "3" inside the circle.
Look for circles with crosses in them to find lights on a German schematic. The color code for the light is displayed next to the symbol. Thermal and magnetic element symbols are similar to the American symbols, except they are encased in a rectangular box. Find thermal elements by looking for an incomplete rectangle extending from the wire, encased in a larger, complete rectangle. Magnetic elements have a rectangle with an "I>" symbol inside them.
Lee Johnson has written for various publications and websites since 2005, covering science, music and a wide range of topics. He studies physics at the Open University, with a particular interest in quantum physics and cosmology. He's based in the UK and drinks too much tea.
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