An electronic symbol is a pictogram used to represent various electrical and electronic devices or functions, such as wires, batteries, resistors, and transistors, in a schematic diagram of an electrical or electronic circuit. These symbols are largely standardized internationally today, but may vary from country to country, or engineering discipline, based on traditional conventions.
The graphic symbols used for electrical components in circuit diagrams are covered by national and international standards, in particular:
The number of standards leads to confusion and errors. Symbols usage is sometimes unique to engineering disciplines and national or local variations to international standards exist. For example, lighting and power symbols used as part of architectural drawings may be different from symbols for devices used in electronics.
IEC-style trace junction
IEC-style chassis-ground symbol
Battery, single cell and multi-cell
(a) resistor, (b) rheostat (variable resistor), and (c) potentiometer (All of them are ANSI style symbols)
Inductor with magnetic core (IEEE Std 315)
American-style relays, SPST, SPDT, DPST, DPDT
Incandescent light bulb (as an indicator)
Moulded Case Circuit Breaker (MCCB)
Microphone (IEEE Std 315)
Loop antenna (IEEE Std 315)
Ferrite bead ring (IEEE Std 315)
The shape of electronic symbols have changed over time. Some symbols were more prevalent in some countries. The following are historic electronic symbols that might be found in old electronic books and schematics.