Printable Chart of Electrical Symbols with their Meanings

Did You Know?

Edraw Max, an electrical diagramming program, was the first software to demonstrate standard electrical symbols on computer screens.

Electrical symbols are used to represent electrical and electronic devices in schematic diagrams. There are different country-specific standards, IEC (British), ANSI, and AS (Australian Standard), that define the symbols used in circuit diagrams across the world. However, today most of the symbols are internationally standardized. We have provided a list of the most commonly used electrical symbols in electrical drawings.

Wire

Passes electric current

DIP

Manual on-off switch used on PCBs

Single Pole, Single Throw (SPST) switch

An on-off switch which passes current in closed position

Single Pole, Double Throw (SPDT) switch

A changeover switch that directs current to one of the two available routes.

Pushbutton (NO)

Momentary switch that passes current when pressed

Pushbutton (NC)

Momentary switch that passes current when released

SPST Relay

On-off switch operated by electromagnet

SPDT Relay

Double throw switch operated by electromagnet

Jumper

Piece of wire that bypasses or closes onboard connections

Solder Bridge

Connection completed by soldering

Ground

Connects to zero potential (or earth)

Chassis Ground

Connects the chassis of a device to zero (earth) potential

Resistor IEEE

IEEE (Institute of Electrical and Electronics Engineers) standard symbol - Reduces flow of charge or current

Resistor IEC

IEC (International Electrotechnical Commission) symbol

Potentiometer IEEE

IEEE symbol - Adjustable resistance value

Potentiometer IEC

IEC symbol

Rheostat IEEE

IEEE symbol - Variable resistance value

Rheostat IEC

IEC symbol

Trimmer

Adjustable resistor with preset value

Thermistor

Resistance value changes due to changes in temperature

Capacitor

Stores electric current

Polarized Capacitor

Capacitors having electrolyte liquid in one of the plates

Variable Capacitor

Can change the value of capacitance

Inductor

Coil that generates magnetic field

Variable Inductor

Can adjust the value of inductance

Iron Core Inductor

Coil core contains iron

Generator

Generates electricity (voltage) by converting mechanical energy to electrical energy

Motor

Converts electrical energy to mechanical energy

Voltmeter

Measures voltage

Ammeter

Measures current

Ohmmeter

Measures resistance

Wattmeter

Measures power

Lamp

Light source illuminated by current flow

Diode

Allows current flow in only one direction

Zener Diode

Allows current flow in reverse direction only above breakdown voltage

Schottky Diode

Diode with less voltage drop

Light Emitting Diode (LED)

Emits light when current flows through

Photodiode

Allows current to flow only when exposed to light

NPN Bipolar Transistor

Current flows only when high potential applied to base

PNP Bipolar Transistor

Current flows only when low voltage applied to base

Transformer

Changes voltage from low to high value or vice-versa

Fuse

Disconnects the circuit if current exceeds threshold value

Electric bell

Produces sound (ringing) when activated

Buzzer

Produces sound (buzzing) when current is applied

Bus

Collection of wires

Optocoupler

Isolates two circuits on a single PCB

Loudspeaker

Converts electrical signal to sound waves

Microphone

Converts sound waves to electrical signals

Operational Amplifier

Amplifies input signals

Schmitt Trigger

Removes noise from input signal

Analog-to-digital Converter

Converts analog signal to digital signal (numbers)

Digital-to-analog Converter

Converts digital signal to analog signal

Crystal Oscillator

Generates frequency clock signal

Antenna

Sends and receives radio waves

Alternating Current (AC)

Supplies current with continuously changing direction

Direct Current (DC)

Supplies current with constant direction

Circuit Breaker

Disconnects the circuit when current crosses threshold value

Earphone

Converts electrical energy to sound waves

Current Transformer

Produces low current when input current is high

Voltage Transformer

Reduces voltage to lower level when it increases beyond safety limits