Electrical Symbols

Electrical Symbols & Electronic SymbolsElectrical symbols and electronic circuit symbols are used for drawing schematic diagram.The symbols represent electrical and electronic components.

Table of Electrical SymbolsSymbol Component name Meaning

Wire Symbols

Electrical Wire Conductor of electrical current

Connected Wires Connected crossing

Not connected Wires Wires are not connected

Switch Symbols and Relay Symbols

SPST Toggle Switch Disconnects current when open

SPDT Toggle Switch Selects between two connections

Pushbutton Switch (N.O) Momentary switch - normally open

Pushbutton Switch (N.C) Momentary switch - normally closed

DIP Switch DIP switch is used for onboard configuration

SPST RelayRelay open / close connection by an electromagnet

SPDT Relay

Jumper Close connection by jumper insertion on pins.

Solder Bridge Solder to close connection

Ground Symbols

Earth Ground Used for zero potential reference and electrical shock protection.

Chassis Ground Connected to the chassis of the circuit

Digital / Common Ground  

Resistor Symbols

Resistor (IEEE)

Resistor reduces the current flow.

Resistor (IEC)

Potentiometer (IEEE)

Adjustable resistor - has 3 terminals.

Potentiometer (IEC)

Variable Resistor / Rheostat(IEEE)

Adjustable resistor - has 2 terminals.Variable Resistor / Rheostat(IEC)

Capacitor Symbols

CapacitorCapacitor is used to store electric charge. It acts as short circuit with AC and open circuit with DC.

Capacitor

Polarized Capacitor Electrolytic capacitor

Polarized Capacitor Electrolytic capacitor

Variable Capacitor Adjustable capacitance

Inductor / Coil Symbols

Inductor Coil / solenoid that generates magnetic field

Iron Core Inductor Includes iron

Variable Inductor  

Power Supply Symbols

Voltage Source Generates constant voltage

Current Source Generates constant current.

AC Voltage Source AC voltage source

Generator Electrical voltage is generated by mechanical rotation of the generator

Battery Cell Generates constant voltage

Battery Generates constant voltage

Controlled Voltage SourceGenerates voltage as a function of voltage or current of other circuit element.

Controlled Current SourceGenerates current as a function of voltage or current of other circuit element.

Meter Symbols

Voltmeter Measures voltage. Has very high resistance. Connected in parallel.

Ammeter Measures electric current. Has near zero resistance. Connected serially.

Ohmmeter Measures resistance

Wattmeter Measures electric power

Lamp / Light Bulb SymbolsLamp / light bulb Generates light when current flows

through

Lamp / light bulb

Lamp / light bulb

Diode / LED Symbols

Diode Diode allows current flow in one direction only (left to right).

Zener Diode

Allows current flow in one direction, but also can flow in the reverse direction when above breakdown voltage

Schottky Diode Schottky diode is a diode with low voltage drop

Varactor / Varicap Diode Variable capacitance diode

Tunnel Diode  

Light Emitting Diode (LED) LED emits light when current flows through

Photodiode Photodiode allows current flow when exposed to light

Transistor Symbols

NPN Bipolar Transistor Allows current flow when high potential at base (middle)

PNP Bipolar Transistor Allows current flow when low potential at base (middle)

Darlington TransistorMade from 2 bipolar transistors. Has total gain of the product of each gain.

JFET-N Transistor N-channel field effect transistor

JFET-P Transistor P-channel field effect transistor

NMOS Transistor N-channel MOSFET transistor

PMOS Transistor P-channel MOSFET transistor

Misc. Symbols

Motor Electric motor

Transformer Change AC voltage from high to low or low to high.

Electric bell Rings when activated

Buzzer Produce buzzing sound

FuseThe fuse disconnects when current above threshold. Used to protect circuit from high currents.

Fuse

Bus

Contains several wires. Usually for data / address.Bus

Bus

Optocoupler / Opto-isolator Optocoupler isolates onnection to other board

Loudspeaker Converts electrical signal to sound waves

Microphone Converts sound waves to electrical signal

Operational Amplifier Amplify input signal

Schmitt Trigger Operates with hysteresis to reduce noise.

Analog-to-digital converter (ADC)

Converts analog signal to digital numbers

Digital-to-Analog converter (DAC)

Converts digital numbers to analog signal

Crystal Oscillator Used to generate precise frequency clock signal

Antenna Symbols

Antenna / aerial

Transmits & receives radio waves

Antenna / aerial

Dipole Antenna Two wires simple antenna

Logic Gates Symbols

NOT Gate (Inverter) Outputs 1 when input is 0

AND Gate Outputs 1 when both inputs are 1.

NAND Gate Outputs 0 when both inputs are 1. (NOT + AND)

OR Gate Outputs 1 when any input is 1.

NOR Gate Outputs 0 when any input is 1. (NOT + OR)

XOR Gate Outputs 1 when inputs are different. (Exclusive OR)

D Flip-Flop Stores one bit of data

Multiplexer / Mux 2 to 1Connects the output to  selected input line.

Multiplexer / Mux 4 to 1

Demultiplexer / Demux 1 to 4

Connects selected output to the input line.

Electronic Components

Electronic components are parts of electrical & electronic circuits. Each component has typical functionality according to its operational characteristics.

Electrical and electronic components tableComponent

ImageComponent

Symbol Component Name

Wire

Toggle switch

Pushbutton switch

  Relay

  Jumper

  Dip switch

Resistor

  Variable resistor / Rheostat

  Potentiometer

Capacitor

Variable capacitor

Electrolytic capacitor

Inductor

Battery

  Voltmeter

Lamp / Light bulb

Diode

BJT Transistor

MOS transistor

  Optocoupler / optoisolator

Electric motor

  Transformer

  Operational amplifier / 741

  Crystal oscillator

Fuse

Buzzer

  Loudspeaker

Microphone

  Antenna / aerial

Passive componentsPassive components do not need additional power source to operate and can not have gain.

Passive components include: wires, switches, resistors, capacitors, inductors, lamps, ...

Active componentsActive components need additional power source to operate and can have gain.Active components include: transistors, relays, power sources, amplifiers, ... 

Diode symbolsThe diode is a semiconductor device that allows the current flow in one direction

only. Valve electronic two electrodes called anode or plate and cathode electrodethat uses the rectifying properties of a material type P and N semiconductor.- These symbols can be represented within a circle.

Symbology

Diode symbolsemiconductor, rectifiergeneral symbol

Diode symbolsemiconductor, rectifier general symbol

Diode symbol

Zener diodelimiting diodeunidirectional breakdown

Zener diode

Zener diode

Zener diode

Zener diode

Varicap diodeVaractor 

Varicap diodeVaractor 

Varicap diodeVaractor 

Gunn Impatt diode

Voltage suppressorBidirectional breakdownDiode 

Voltage suppressorDiode 

Constant current diode

Recovery diode instantSnap 

Tunnel diode 

Tunnel diode 

Tunnel rectifier diode

Schottky diode

Pin diode

Pin diode

Photodiode 

LEDlight emitting diode

Photodiode NPNbidirectional

Photodiodetwo segmentsPNP common cathode 

Photodiodetwo segmentsPNP common cathode 

Laser diode

Magnetic diode

Temperature sensitivediode

Diode NPNBidirectional breakdown

Diode PNPBidirectional breakdown

Bridge rectifier by 4 diodes 

Bridge rectifier by 4 diodes 

7-Segment displayLED diodes 

Bicolor LEDdual polarity 

5x7 LED alphanumericsample letter A

Tiristor SCR e díodo:

No caso do tiristor SCR este se assemelha a uma fechadura pelo fato da corrente poder fluir pelo dispositivo em um único sentido, entrando pelo terminal de anodo e saindo pelo terminal de catodo. No entanto difere de um diodo porque mesmo quando o dispositivo está diretamente polarizado ele não consegue entrar em condução enquanto não ocorrer a ativação do seu terminal de controle (terminal denominado porta, ou gate em inglês)

ReostatoFunção Simbolo Foto

é um resistência variável com dois terminais, sendo um fixo e o outro deslizante. Geralmente são utilizados com altas correntes.Variação Contínua: O reostato de variação contínua, comumente denominado potenciômetro, apresenta uma resistência que pode ter qualquer valor entre zero e um valor máximo específico.

Potenciômetro 

Função Simbolo Foto

É um tipo de resistência variável comum, sendo normalmente utilizado para controlar o volume em amplificadores de áudio, variadores de tensão, tudo o que é ajustável em função de um valor variável de uma resistência.

Resistor symbolsThe resistors are passive components manufactured specifically to deliver a

given value of resistance to the passage of electric current.The resistors are mainly classified into fixed, variable and special.

Um resistor (frequentemente chamado de resistência, que é na verdade a sua medida) é um dispositivo elétrico muito utilizado em eletrônica, ora com a finalidade de transformar energia elétrica em energia térmica por meio do efeito joule, ora com a finalidade de limitar a corrente elétrica em um circuito.[1]

Resistores são componentes que têm por finalidade oferecer uma oposição à passagem de corrente elétrica, através de seu material. A essa oposição damos o nome de

resistência elétrica, que possui como unidade o ohm. Causam uma queda de tensão em alguma parte de um circuito elétrico, porém jamais causam quedas de corrente elétrica. Isso significa que a corrente elétrica que entra em um terminal do resistor será exatamente a mesma que sai pelo outro terminal, porém há uma queda de tensão. Utilizando-se disso, é possível usar os resistores para controlar a corrente elétrica sobre os componentes desejados.

Um resistor ideal é um componente com uma resistência elétrica que permanece constante independentemente da tensão ou corrente elétricaque circular pelo dispositivo.

Os resistores podem ser fixos ou variáveis. Neste caso são chamados de potenciômetros ou reostatos. 

Variable resistorRheostat

Variable resistorpreset 

Variable resistorRheostat

Variable resistorpreset 

Step varaible resistor

Impedance

Step varaible resistor

Variable resistor

Potentiometer 

Resistor of variationcontinuous

Variable resistorPotentiometer

Thermistor, NTCNegative temperature coefficient 

Preset potentiometer

Thermistor, PTCPositive temperature coefficient 

Thermistor

Photoresistor, LDRLight dependent resistor 

Varistor, VDRVoltage dependent resistor 

Photoresistor, LDRLight dependent resistor

Varistor, VDRVoltage dependent resistor

Photoresistor, LDRLight dependent resistor

Varistor, VDRVoltage dependent resistor

Photoresistor, LDRLight dependent resistor

Varistor, VDRVoltage-dependent resistor 

Resistorwith power supply

Resistorwith fixed tappings

Resistor dependent magnetic field

Attenuator

Protection resistor

Protection resistor

Resistor not flammable 

Heating element

Preset resistor

Derivation resistorconnections currentand voltage