Electronic symbol


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.

Standards for symbols

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.

Common electronic symbols

Symbols shown are typical examples, not a complete list.

Traces

Grounds

Optionally, the triangle in the following symbol may be filled in.

Resistors

It is very common for potentiometer and rheostat symbols to be used for many types of variable resistors, including trimmers.

Capacitors

Diodes

Optionally, the triangle in these symbols may be filled in. There are multiple ways to draw a Bridge Rectifier symbol.

Inductors

Transformers

Transistors

Unipolar

Optionally, these symbols may include a circle.

Bipolar

Optionally, these symbols may include a circle.

Vacuum tubes

Switches

Relays

Lamps

Current limiters

Electro-acoustic devices

Antennas

Connectors

ICs

Miscellaneous devices

Historical electronic symbols

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.

Capacitors (historical)