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 standards do not all agree, and use of unusual (even if standardized) symbols can lead to confusion and errors. Symbols usage is sometimes idiosyncratic 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

[Wire crossover symbols for circuit diagrams. The CAD symbol for insulated crossing wires is the same as the older, non-CAD symbol for non-insulated crossing wires. To avoid confusion, the wire "jump" (semi-circle) symbol for insulated wires in non-CAD schematics is recommended (as opposed to using the CAD-style symbol for no connection), so as to avoid confusion with the original, older style symbol, which means the exact opposite. The newer, recommended style for 4-way wire connections in both CAD and non-CAD schematics is to stagger the joining wires into T-junctions.

The large dot signifies an electrical connection. | upload.wikimedia.org/wikipedia/commons/3/36/Wire///Crossover///Symbols///for///Circuit///Diagrams.png]

Grounds

The shorthand for ground is GND. Optionally, the triangle in the middle symbol may be filled in.

Sources

Resistors

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

Capacitors

Diodes

Optionally, the triangle in these symbols may be filled in. Note: The words anode and cathode typically aren't part of the diode symbols.

Bridge rectifiers

There are many ways to draw a single-phase bridge rectifier symbol. Some show the internal diode circuit, some don't.

Inductors

An inductor can be drawn either as a series of loops, or series of half-circles.

Transformers

Transistors

Optionally, transistor symbols may include a circle. Note: The pin letters B/C/E and G/D/S aren't part of the transistor symbols.

Bipolar

Unipolar

Vacuum tubes

Switches

For multiple pole switches, a dotted or dashed line can be included to indicate two or more switch at the same time (see DPST and DPDT examples below).

Relays

Relays symbols are a combination of an inductor symbol and switch symbol. Note: The pin letters in these symbols aren't part of the standard relay symbol.

Lamps

LED are located in the diode section.

Current limiters

Electro-acoustic devices

Speaker symbols sometimes include an internal inductor symbol.

Antennas

Cables

Connectors

There are numerous connector symbol variations.

ICs

Logic gates

For the symbols below: A and B are inputs, Q is output. Note: These letters are not part of the symbols. There are variations of these logic gate symbols. Depending on the IC, the two-input gates below may have: 1) two or more inputs; 2) infrequently some have a second inverted Q output too.

Flip-flops

For the symbols below: Q is output, Q is inverted output, E is enable input, internal triangle shape is clock input, S is Set, R is Reset (some datasheets use clear (CLR) instead of reset along the bottom). There are variations of these flip-flop symbols. Depending on the IC, a flip-flop may have: 1) one or both outputs (Q only, Q only, both Q & Q); 2) one or both forced inputs along top & bottom (R only, S only, both R & S); 3) some inputs may be inverted.

OpAmps

Note: The outside text isn't part of these symbols.

Oscillators

Miscellaneous devices

Historical electronic symbols

The shape of some electronic symbols have changed over time. The following historical electronic symbols can be found in old electronic books / magazines / schematics, and now considered obsolete.

Capacitors (historical)

All of the following are obsolete capacitor symbols.