An electronic symbol is a pictogram used to represent various electrical and electronic devices (such as wires, batteries, resistors, and transistors) in a schematic diagram of an electrical or electronic circuit. These symbols can (because of remaining traditions) vary from country to country, but are today to a large extent internationally standardized. Some symbols represent components (such as vacuum tubes) which ceased to be used routinely as newer technologies were introduced.
Electronic symbol Wikipedia
There are several national and international standards for graphical symbols in circuit diagrams, in particular:IEC 60617 (also known as British Standard BS 3939).
ANSI standard Y32.2 (also known as IEEE Std 315).
IEEE Std 91/91a: graphic symbols for logic functions (used in digital electronics). It is referenced in ANSI Y32.2/IEEE Std 315.
Australian Standard AS 1102.
Different symbols may be used depending on the discipline using the drawing. For example, lighting and power symbols used as part of architectural drawings may be different from symbols for devices used in electronics. National and local variations to international standards also exist.
Symbols shown are typical examples, not a complete list.