Electronics and Electrical Symbols

February 9, 2021

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Electrical symbols are a graphical representation of basic electrical and electronic devices or components. These Symbols are used in circuit and electrical diagrams to recognize a component. It is also called a schematic symbol. Each component has typical functionality according to its operational characteristics.

An electronic circuit or schematic drawing uses a wired path between electronic components to complete the circuit. These components are represented by respective symbols for it.

Electrical and electronic symbols used in circuits are defined with various national and international standards. E.g. IEC standard, JIC standard, ANSI standard, IEEE standard, etc.,

Though electrical symbols are standardized, may vary from country to country, or engineering discipline, based on traditional conventions.

This enables anyone to read electrical circuits or schematic diagrams and floor plans with ease and clarity.

Electrical symbols represent the components of electrical and electronic circuits and do not define any function or process unless the circuit is implemented with components being physically used. (E.g. the circuit on breadboard or assembled printed circuit board)

There is a circuit symbol for each, and every electrical component or device used in a circuit such as passive components, active components, measuring instruments, logic gates etc.

A few electronic symbols that can be used in the circuit diagrams is given below for reference:

Wire Symbols

Electrical wire

Connected wires

Not Connected wires

Ground Symbols

Earth Ground

Chassis Ground

Digital/Common Ground

Inductor/Coil Symbols

Inductor

Iron Core Inductor

Variable Inductor

Definition of an Inductor: It is a device that temporarily stores energy in the form of a magnetic field.

Lamp/Light Bulb Symbols

Lamp / light bulb

Switch and Relay Symbols

SPST Toggle Switch

SPDT Toggle Switch

Jumper

DIP Switch

Pushbutton Switch (N.C)

Pushbutton Switch (N.O)

SPST Relay/SPDT Relay

Solder Bridge

Definition of a Relay: It controls circuits by opening and closing contacts in another circuit. Relays switches are used to open and close circuits electromechanically or electronically.

Resistor Symbols

Resistor (IEEE)/ Resistor (IEC)

Potentiometer (IEEE)/(IEC)

Variable Resistor / Rheostat (IEEE)/(IEC)

Trimmer Resistor

Thermistor

Photoresistor / Light-dependent resistor (LDR)

Definition of a Resistor: As the name suggests, they resist the flow of excessive electrical power or voltage passing through the circuit, in a precise and controlled manner.