Electronics and Electrical Symbols

By Madhusoodan S ([email protected])

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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 Electrical 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

Electrical wire

Connected wires

Not Connected wires

Not Connected wires

Ground Symbols

Earth Ground

Earth Ground

Chassis Ground

Chassis Ground

Digital/Common Ground

Digital/Common Ground

 

Inductor/Coil Symbols

Inductor

Inductor

Iron Core Inductor

Iron Core Inductor

Variable 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

Lamp / light bulb

Lamp / light bulb

Lamp / light bulb

Lamp / light bulb

Lamp / light bulb

Switch and Relay Symbols

SPST Toggle Switch

SPST Toggle Switch

SPDT Toggle Switch

SPDT Toggle Switch

Jumper

Jumper

DIP Switch

DIP Switch

Pushbutton Switch (N.C)

Pushbutton Switch (N.O)  Pushbutton Switch (N.O) 

SPST Relay/SPDT Relay

SPST Relay/SPDT Relay

Solder Bridge

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)

Potentiometer (IEEE)/(IEC)

Variable Resistor / Rheostat (IEEE)/(IEC)

Variable Resistor / Rheostat (IEEE)/(IEC)

Trimmer Resistor

Thermistor

Photoresistor / Light dependent resistor (LDR)

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.

Capacitor symbols

Capacitor

Capacitor

Polarized Capacitor

Polarized Capacitor

Variable Capacitor

Variable Capacitor


Definition of a Capacitor:
It is a device that is used to store electrical energy in an electric field. It is a passive electronic component.

Antenna Symbols

Antenna / aerial

Antenna / aerial

Antenna / aerialAntenna / aerial

Dipole Antenna

Dipole Antenna

Definition of an Antenna: It is an electrical device that converts electric power into radio waves and vice versa.

Power Supply Symbols

Voltage Source/ Current Source

Battery Cell/ Battery

Battery Cell/ Battery

Controlled voltage source/Controlled Current source

Controlled voltage source/Controlled Current source

AC voltage source/Generator

AC voltage source/Generator

 

Meter Symbols

Voltmeter/Ammeter

Voltmeter/Ammeter

Ohmmeter/Wattmeter

Ohmmeter/Wattmeter

 

Diode/LED Symbols

Diode/Zener Diode

Diode/Zener Diode

Tunnel Diode/Light Emitting Diode

Tunnel Diode/Light Emitting Diode

Schottky Diode/Varicap Diode

Schottky Diode/Varicap Diode

Photodiode

Photodiode


Definition of a LED:
It is a semiconductor device that emits light when an electric current is passed through it.

Transistor Symbols

NPN Bipolar Transistor/ PNP Bipolar Transistor

NMOS/PMOS Transistor

JFET-N Transistor/ JFET-P Transistor

JFET-N Transistor/ JFET-P Transistor

Darlington Transistor

Darlington Transistor


Definition of a Transistor:
It is a semiconductor device used to amplify or switch electronic signals and electrical power.

Miscellaneous Symbols

Motor/ Transformer

Motor/ Transformer

Fuse

Fuse

Electric bell/Buzzer

Electric bell/Buzzer

Microphone / Loudspeaker

Microphone / Loudspeaker

Op-amp /Schmitt trigger

Op-amp /Schmitt trigger

Bus

Bus

Bus

Bus

Analog-to-Digital Converter (ADC)

Digital-to-Analog converter (DAC)

Digital-to-Analog Converter (DAC)

Optocoupler

Optocoupler

Crystal Oscillator

Crystal Oscillator

 

Logic Gate Symbols

AND /NAND Gate

AND /NAND Gate

XOR Gate / NOT Gate

XOR Gate / NOT Gate

OR /NOR Gate

OR /NOR Gate

D flip flop /Multiplexer(MUX) 2 to 1

D flip flop /Multiplexer(MUX) 2 to 1

 


To read other interesting Electronics basics: click here

This article was first published on 18 April 2020 and was updated on 9 February 2021.

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