Electronic Circuit Symbols

In electronic circuits, there are many electronic symbols that are used to represent or identify a basic electronic or electrical device. They are mostly used to draw a circuit diagram and are standardized internationally by the IEEE standard (IEEE Std 315) and the British Standard (BS 3939). NO changes can be brought by the user on any electronic symbol, but the user is free to bring any changes in the architectural drawings like power source and lighting.

Electronic Symbols

The symbols for different electronic devices are shown below. Click on each link given below to view the symbols. Apart from the circuit symbols, each device is also designated a short name. Though these names are not approved as standard notations, they are commonly used by most people. These designations are also given in the list.

Wires | Power Supplies | Resistor | Capacitor |Diode | Transistor | Logic Gates | Meters | Sensors | Switches | Audio and Radio Devices | Output Devices

Wires

Electronic Component Circuit Symbol Description
Wire
Wire Circuit Symbol

Wire Circuit Symbol

Used to connect one component to another.

  Wires Joined
Wires Joined Circuit Symbol

Wires Joined Circuit Symbol

 

One device may be connected to another through wires. This is represented by drawing “blobs” on the point where they are shorted.

  Unjoined Wires
Wires Not Joined Circuit Symbol

Wires Not Joined Circuit Symbol

When circuits are drawn some wires may not touch others. This can only be shown by bridging them or by drawing them without blobs. But bridging is commonly practised as there will not arise any confusion.

 

Power Supplies

Electronic Component Circuit SymbolDescription
  Cell
Cell Circuit Symbol

Cell Circuit Symbol

 

Used to provide a supply for a circuit.

Battery
Battery Circuit Symbol

Battery Circuit Symbol

A battery has more than a cell and is used for the same purpose. The smaller terminal is negative and the larger one is positive. Abbreviated as ‘B’.

DC Supply
DC Supply Circuit Symbol

DC Supply Circuit Symbol

Used as a DC power supply, that is, the current will always flow in one direction.

AC Supply
AC Supply Circuit Symbol

AC Supply Circuit Symbol

Used as AC power supply, that is, the current will keep alternating directions.

Fuse
Fuse Circuit Symbol

Fuse Circuit Symbol

Used in circuits where a probability of excessive current flows. The fuse will break the circuit if excessive current flows and saves the other devices from damage.

  Transformer
Transformer Circuit Symbol

Transformer Circuit Symbol

 

Used as an ac power supply. Consists of two coils, the primary and secondary that are linked together through an iron core. There is no physical connection between the two coils. The principle of mutual inductance is used to obtain power. Abbreviated as ‘T’.

Earth/Ground
Earth Circuit Symbol

Earth Circuit Symbol

Used in electronic circuits to represent the 0 volts of the power supply. It can also be defined as the real earth , when it is applied in radio circuits and power circuits.

 

Resistor

Electronic Component Circuit SymbolDescription
Resistor  
Resistor Circuit Symbol

Resistor Circuit Symbol

A resistor is used to restrict the amount of current flow through a device. Abbreviated as ‘R’.

Rheostat
Rheostat Circuit Symbol

Rheostat Circuit Symbol

A rheostat is used to control the current flow with two contacts. Applicable in controlling lamp brightness, capacitor charge rate, etc.

Potentiometer
Potentiometer Circuit Symbol

Potentiometer Circuit Symbol

A potentiometer is used to control the voltage flow and has three contacts. Have applications in changing a mechanical angle change to an electrical parameter. Abbreviated as ‘POT’.

Preset
Preset Circuit Symbol

Preset Circuit Symbol

Presets are low cost variable resistors that are used to control the charge flow with the help of a screw driver. Applications where the resistance is determined only at the end of the circuit design.

 

Capacitor

Electronic Component Circuit SymbolDescription
Capacitor
Capacitor Circuit Symbol

Capacitor Circuit Symbol

Capacitor is a device that is used to store electrical energy. It consists of two metals plates that are separated by a dielectric. It is applicable as a filter, that is, to block DC signals and allow AC signals. Abbreviated with the letter ‘C’.

Capacitor - Polarized
Capacitor-Polarised Circuit Symbol

Capacitor-Polarised Circuit Symbol

Capacitor can be used in a timer circuit by adding a resistor.

Variable Capacitor
Variable Capacitor Circuit Symbol

Variable Capacitor Circuit Symbol

Used to vary the capacitance by turning the knob. A type of variable capacitor is the trimmer capacitor that is small in size. The notations are all the same.

Diode

Electronic Component Circuit SymbolDescription
Diode
Diode Circuit Symbol

Diode Circuit Symbol

A diode is used to allow electric current to flow in only one direction. Abbreviated as ‘D’.

Light Emitting Diode (LED)
LED Circuit Symbol

LED Circuit Symbol

LED is used to emit light when a current is passed through the device. It is abbreviated as LED.

Zener Diode
Zener Diode Circuit Symbol

Zener Diode Circuit Symbol

After a breakdown voltage, the device allows current to flow in the reverse direction as well. It is abbreviated as ‘Z’.

Photo Diode
Photo Diode Circuit Symbol

Photo Diode Circuit Symbol

Photodiode works as a photo-detector and converts light into its corresponding voltage or current.

Tunnel Diode
Tunnel Diode Circuit Symbol

Tunnel Diode Circuit Symbol

Tunnel Diode is known for its high-speed operation due to its application in quantum mechanical effects.

Schottky Diode
Schottky Diode Circuit Symbol

Schottky Diode Circuit Symbol

The Schottky Diode is known for its large forward voltage drop and hence has great applications in switching circuits.

Transistor

Electronic Component Circuit SymbolDescription
  NPN Transistor
Transistor NPN Circuit Symbol

Transistor NPN Circuit Symbol

 

This is a transistor with a layer of P-doped semiconductor fixed between two layers of N-doped semiconductors that act as the emitter and collector. Abbreviated as ‘Q’.

  PNP Transistor
Transistor PNP Circuit Symbol

Transistor PNP Circuit Symbol

 

This is a transistor with a layer of N-doped semiconductor fixed between two layers of P-doped semiconductors that act as the emitter and collector. Abbreviated as ‘Q’.

  Phototransistor
Phototransistor Circuit Symbol

Phototransistor Circuit Symbol

 

The working of a phototransistoris similar to that of a bipolar transistor with a difference that it converts light into its corresponding current. The phototransistor can also act as a photodiode if the emitter is not connected.

Field Effect Transistor
Field Effect Transistor Circuit Symbol

Field Effect Transistor Circuit Symbol

Like a transistor, a FET has three terminals, the Gate, Source and Drain. The device has an electric field that controls the conductivity of a channel of one type charge carrier in a semiconductor substance.

N-Channel Junction FET
n-channel Junction Field Effect Transistor (JFET) Circuit Symbol

n-channel Junction Field Effect Transistor (JFET) Circuit Symbol

The Junction Field Effect Transistor (JFET) is the simplest type of FET with applications in Switching and voltage variable resistor. In an N-channel JFET an N-type silicon bar has two smaller pieces of P-type silicon material diffused on each sides of its middle part, forming P-N junctions.

P-Channel Junction FET
p-channel Junction Field Effect Transistor (FET) Circuit Symbol

p-channel Junction Field Effect Transistor (FET) Circuit Symbol

P-channel JFET is similar in construction to N-channel JFET except that P-type semiconductor base is sandwiched between two N-type junctions. In this case majority carriers are holes.

Metal Oxide Semiconductor FET Given Below

Abbreviated as MOSFET. MOSFET is a three terminal device and is controlled by a gate bias. It is known for its low capacitance and low input impedance.

  Enhancement MOSFET
e-MOSFET Circuit Symbol

e-MOSFET Circuit Symbol

 

The enhancement MOSFET structure has no channel formed during its construction. Voltage is applied to the gate, so as to develop a channel of charge carriers so that a current results when a voltage is applied across the drain-source terminals. Abbreviated as e-MOSFET.

  Depletion MOSFET
d-MOSFET Circuit Symbol

d-MOSFET Circuit Symbol

 

In the depletion-mode construction a channel is physically constructed and a current between drain and source is due to voltage applied across the drain-source terminals. Abbreviated as d-MOSFET.

Logic Gates

Gate Standard Symbol IEC Symbol Description
  AND Gate
AND GATE Symbol

AND GATE Symbol

AND Gate IEC Symbol

AND Gate IEC Symbol

 

If all the inputs of an AND gate are HIGH, then the output will also be HIGH. If any one of them is LOW, the output will also be LOW.

NAND Gate
NAND Gate Symbol

NAND Gate Symbol

NAND Gate IEC Symbol

NAND Gate IEC Symbol

Short form for NOT AND Gate. Of all the inputs are HIGH, the output will be LOW. If any one input is LOW, the output will be HIGH.

  OR Gate
OR Gate Symbol

OR Gate Symbol

OR Gate IEC Symbol

OR Gate IEC Symbol

 

If any one of the input is HIGH, the output will also be HIGH. If both inputs are LOW, the output will also be LOW.

  NOR Gate
NOR Gate Symbol

NOR Gate Symbol

NOR Gate IEC Symbol

NOR Gate IEC Symbol

 

Short form for NOT OR. If both inputs are LOW, the output will also be LOW. For other cases, the output will be HIGH.

  EX-OR Gate
EX-OR Gate Symbol

EX-OR Gate Symbol

EX-OR Gate IEC Symbol

EX-OR Gate IEC Symbol

 

Short form for Exclusive NOR. If both inputs are either in LOW state r HIGH state, the output will be LOW. If both inputs are different, the output will be HIGH.

  EX-NOR Gate
EX-NOR Gate Symbol

EX-NOR Gate Symbol

EX-NOR Gate IEC Symbol

EX-NOR Gate IEC Symbol

 

Short form for Exclusive NOT OR. If both the inputs are the same, the output will be HIGH. If both are different, the output will also be different.

  NOT Gate
NOT Gate  Symbol

NOT Gate Symbol

NOT Gate  Symbol

NOT Gate Symbol

 

Also known as the inverter Gate. There is only one input for this gate. If the input is HIGH, the output will be LOW. If the input is LOW, the output will be HIGH.

Meters

Electronic Component Circuit SymbolDescription
  Voltmeter
Voltmeter Circuit Symbol

Voltmeter Circuit Symbol

 

Voltmeter is used to measure the voltage at a certain point in the circuit.

Ammeter
Ammeter Circuit Symbol

Ammeter Circuit Symbol

An Ammeter is used to measure the current that passes through the circuit at a particular point.

Galvanometer
Galvanometer Circuit Symbol

Galvanometer Circuit Symbol

A galvanometer is used to measure very small currents in the order of 1 milli ampere or less.

  Ohmmeter
Ohmmeter Circuit Symbol

Ohmmeter Circuit Symbol

 

Resistance of the circuit is measured using an Ohmmeter.

Oscilloscope
Oscilloscope Circuit Symbol

Oscilloscope Circuit Symbol

An oscilloscope is used to measure the voltage and time period of signals along with their shape display.

Sensors

Electronic Component Circuit SymbolDescription
Light Dependent Resistor (LDR)
LDR Circuit Symbol

LDR Circuit Symbol

It is abbreviated as LDR. Light Dependent Resistor is used to convert light into its corresponding resistance. Instead of directly measuring the light, it senses the heat content and converts it onto resistance.

Thermistor
Thermistor Circuit Symbol

Thermistor Circuit Symbol

Instead of directly measuring the light, a thermistor senses the heat content and converts it into resistance. Abbreviated as ‘TH’.

Switches

Electronic Component Circuit SymbolDescription
  Push Switch
Push Switch Circuit Symbol

Push Switch Circuit Symbol

 

This is an ordinary switch that passes current only upon pressing.

  Push to Break Switch
Push to Break Switch Circuit Symbol

Push to Break Switch Circuit Symbol

 

The push to break switch is usually kept in the ON state (closed). It turns to OFF state (open) only when the switch is pressed.

  Singe Pole Single Throw Switch
On Off Switch (SPST) Circuit Symbol

On Off Switch (SPST) Circuit Symbol

 

Also known as the ON/OFF switch. This switch allows the flow of current only when it is kept ON. Abbreviated as SPST.

Single Pole Double Throw Switch
2-Way Switch (SPDT) Circuit Symbol

2-Way Switch (SPDT) Circuit Symbol

Also known as the 2-way switch. It can be also called as an ON/OFF/ON switch as it has an OFF position in the center. The switch causes the flow of current in two directions, depending on its position. It can be abbreviated as SPDT.

Double Pole Single Throw Switch
Dual On-Off Switch (DPST) Circuit Symbol

Dual On-Off Switch (DPST) Circuit Symbol

Abbreviated as DPST. Can also be called as a dual ON-OFF switch. This is used to isolate between the live and neutral connections in the main electrical line.

Double Pole Double Throw Switch
DPDT Circuit Symbol

DPDT Circuit Symbol

Abbreviated as DPDT. The switch uses a central OFF position and is applied as reversing switch for motors.

  Relay
Relay Circuit Symbol

Relay Circuit Symbol

 

Relay is abbreviated as ‘RY’. This device can easily switch a 230 Volt AC mains circuit. It has three switching stages called Normally Open (NO). Normally Closed (NC), and Common (COM).

Audio and Radio Devices

Electronic Component Circuit SymbolDescription
Microphone
Microphone Circuit Symbol

Microphone Circuit Symbol

This device is used for converting sound to its corresponding electrical energy. Abbreviated as ‘MIC’.

Earphone
Earphone Circuit Symbol

Earphone Circuit Symbol

Does the reverse process of microphone and converts electrical energy into sound.

Loudspeaker
Loudspeaker Circuit Symbol

Loudspeaker Circuit Symbol

Does the same operation as an earphone, but converts an amplified version of the electrical energy into its corresponding sound.

Piezo-Transducer
PiezoTransducer Circuit Symbol

PiezoTransducer Circuit Symbol

It is a transducer that converts electrical energy into sound.
Amplifier
Amplifier Circuit Symbol

Amplifier Circuit Symbol

Used to amplify a signal. It is mainly used to represent a whole circuit rather than just one component.

Aerial
Aerial  Circuit Symbol

Aerial Circuit Symbol

This device is used to transmit/receive signals. Abbreviated as ‘AE’.

Output Devices

Electronic Component Circuit SymbolDescription
Lighting Lamp
Lamp Circuit Symbol

Lamp Circuit Symbol

This is used to provide light for the output.

Indicator Lamp
Lamp Indiator Circuit Symbol

Lamp Indiator Circuit Symbol

Used to convert electrical energy into light. The best example is the warning light on a car dashboard.

Heater
Heater Circuit Symbol

Heater Circuit Symbol

This transducer is used to change electrical energy into heat.

Inductor
Inductor Circuit Symbol

Inductor Circuit Symbol

Inductor is used to produce a magnetic field when a certain current is passed through a coil of wire. The wire is coiled on a soft iron core. Have applications in motors, and tank circuits. Abbreviated as ‘L’.

Motor
Motor Circuit Symbol

Motor Circuit Symbol

This device is used to convert electrical energy into mechanical energy. Can be used as a generator as well. Abbreviated as ‘M’.

Bell
Bell Circuit Symbol

Bell Circuit Symbol

Used to produce a sound as the output, according to the electrical energy produced as the input.

Buzzer
Buzzer Circuit Symbol

Buzzer Circuit Symbol

It is used to produce an output sound corresponding to the electrical energy in the input.