Name Electrical Symbol Alternate Symbol Description

This symbol
Standard Electrical Symbols For Electrical identifies an
earth(ground)
Schematic Diagrams terminal used
for a zero
ground/earth
potential
reference point
and electrical
shock
protection.
It is a symbol to
identify parts
with the same
voltage (i.e., the
same electrical
potential or
equipotential).
Since
equipotential
surfaces all
have the same
equipotential voltage, you
won't be
shocked if you
touch two such
surfaces unless
you are also
touching
another part
with a different
potential from
the first two
parts.
chassis ground It is a link
between
different
metallic parts of
a machine to
ensure an
 electrical
connection
between them.
It must not be
considered as a
link to the
earth.
It is a device
that consists of
one or more
electrochemical
cells with
external
battery connections to
empower
electrical
devices and
generates
constant
voltages.
It is an electrical
component that
reduces the
electric current,
for example, to
limit the current
resistor
passing
through an LED.
A resistor is
used with a
capacitor in a
timing circuit.
attenuator It is an
electronic
device that
reduces the
power of a
signal with
appreciably
distorting its
 waveform,
which is the
opposite of an
amplifier.
It is a device
with two
terminals, which
stores electric
energy. The
effect of a
capacitor is
capacitor
known as
capacitance. It
can also be
used as a filter
to block DC
signals but pass
AC signals.
It is an energy
storage device
that accepts,
stores, and
accumulator releases energy,
increasing or
relieving
pressure in the
system.
An antenna also
knows as an
aerial, is a
device designed
antenna to transmit or
receive
electromagnetic
(e.g., TV or
radio) waves.
loop antenna A loop antenna
is a radio
antenna
consisting of a
 loop (or loops)
of wire, tubing,
or other
electrical
conductors with
its ends
connected to a
balanced
transmission
line.
A crystal
oscillator uses
the mechanical
resonance of a
vibrating crystal
crystal of piezoelectric
material to
create an
electrical signal
with an exact
frequency.
A circuit
breaker is an
automatically
operated
electrical switch
designed to
circuit breaker
protect an
electrical circuit
from damage
caused by
overload or
short circuit.
fuse A fuse is an
electrical safety
device that
operates to
provide
overcurrent
protection of an
 electrical circuit.
An ideal voltage
source is a two-
terminal device
that maintains a
fixed voltage
drop across its
ideal source
terminals. It is
often used in
the simplified
analysis process
of a real electric
circuit.
generic component
A transducer is
a device that
converts energy
from one form
to another.
Usually, a
transducer
transducer
converts a
signal in one
type of power
to a signal in
another.
inductor A coil of wire
creates a
magnetic field
when current
passes through
it. It may have
an iron core
inside the coil.
It can be used
as a transducer
converting
electrical
energy to
mechanical
 energy by
pulling on
something. It is
a passive two-
terminal
electrical
component
used to store
energy in a
magnetic field.

half inductor

pickup head

pulse

saw tooth

step function
Explosive squib
is often used on
stage and film
explosive squib
to trigger
various special
effects.
sensing link squib

squib igniter
Surge
protectors
protect your
surge protectors electronics from
power surges in
your electrical
system.
 For example, a
voltmeter is an
instrument
used for
measuring the
electrical
potential
difference
between two
instrument
points in an
electric circuit.
The wattmeter
is an instrument
for measuring
the electric
power in watts
of any given
circuit.

material

The delay
element
provides a
specified delay
delay element between the
actuation of the
propellant-
actuated
devices.
A permanent
magnet is a
material or
permanent magnet
object that
produces a
magnetic field.

magnet core

ferrite core
igniter plug

The electric bell

is found in an
ordinary house
bell doorbell, and
when activated,
it makes a
ringing sound.
An electrical
buzzer is similar
to the bell that
makes a
buzzer
constant buzz
noise instead of
a single tone or
bell sound.
thermal element

thermocouple

thermopile

A transducer
converts
electrical
energy to light,
used for a lamp
lamp
providing
illumination, for
example, a car
headlamp or
torch bulb.
fluorescent lamp
speaker A speaker can
take digital
input and turn
it into analog
sound waves—
one of the most
 important parts
of a wide range
of electrical
products like
TVs and
telephones.

microphone

It produces a
repetitive
electronic
oscillator
signal, often a
sine wave or a
square wave.
Alternating
Current,
AC source continually
change
direction.

Direct Current,
DC source always flow in
one direction
Electrical Symbols & Electronic Symbols
Electrical symbols and electronic circuit symbols are used for drawing schematic
diagram.
The symbols represent electrical and electronic components.

Table of Electrical Symbols

Symbo
l
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 Relay
Relay open / close connection by an
electromagnet
SPDT Relay

Jumper Close connection by jumper insertion on pins.

Solder Bridge Solder to close connection

Ground Symbols
Used for zero potential reference and electrical
Earth Ground
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)

Trimmer Resistor Preset resistor

Thermal resistor - change resistance when

Thermistor
temperature changes

Photoresistor / Light Photo-resistor - change resistance with light

dependent resistor (LDR) intensity change

Capacitor Symbols

Capacitor
Capacitor 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

Electrical voltage is generated by mechanical

Generator
rotation of the generator

Battery Cell Generates constant voltage

Battery Generates constant voltage

Generates voltage as a function of voltage or

Controlled Voltage Source
current of other circuit element.

Generates current as a function of voltage or

Controlled Current Source
current of other circuit element.

Meter Symbols
Measures voltage. Has very high resistance.
Voltmeter
Connected in parallel.
 Measures electric current. Has near zero
Ammeter
resistance. Connected serially.

Ohmmeter Measures resistance

Wattmeter Measures electric power

Lamp / Light Bulb Symbols

Lamp / light bulb

Lamp / light bulb Generates light when current flows through

Lamp / light bulb

Diode / LED Symbols

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

Allows current flow in one direction, but also can

Zener Diode 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 allows current flow when exposed to

Photodiode
light

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

Allows current flow when low potential at base

PNP Bipolar Transistor
(middle)

Made from 2 bipolar transistors. Has total gain of

Darlington Transistor
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

Change AC voltage from high to low or low to

Transformer
high.
Electric bell Rings when activated

Buzzer Produce buzzing sound

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

Bus

Bus Contains several wires. Usually for data / address.

Bus

Optocoupler / Opto-isolator Optocoupler isolates connection 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
Converts analog signal to digital numbers
(ADC)
 Digital-to-Analog converter
Converts digital numbers to analog signal
(DAC)

Crystal Oscillator Used to generate precise frequency clock signal

⎓ Direct current
Direct current is generated from constant voltage
level

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)

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

D Flip-Flop Stores one bit of data

Multiplexer / Mux 2 to 1

Connects the output to  selected input line.

Multiplexer / Mux 4 to 1

Demultiplexer / Demux 1 to 4 Connects selected output to the input line