Circuit diagram execution standard of graphic symbol and text symbols

In order to facilitate communication, in reference to the international electrotechnical commission ( IEC) Issued by the relevant documents, made the electrical equipment related to the national standard, enacted GB4728 - - 1984 the electrical diagrams with a graphical symbol, GB 5465 - 1985 the electrical equipment use graphic symbol, the drawing principle, GB 6988 - The electrical drawings, GB 5094-1986 Electrical technology in the project code and GB 1985-7159 - 1987 to establish the general principles of the 'the text symbols in the electrical technology, regulations from 1, 1, 1990, the electric diagram of the graphic symbol and text symbols must comply with the latest national standards. ( 1) Graphic symbol by symbol elements, limited symbols, the general symbol and action of non-electric operation control symbols ( Such as mechanical control symbols, etc. ) According to the different situation that constitute the specific device. ( 2) Text symbols basic text symbols, single alphabetic character and double letter symbol categories of electrical equipment, devices and components, such as K as relay such elements as the categories; The alphabetic character from a single letter said categories and another said device features of letters, for example, said the relay type element of KA for intermediate relay.