Electronic Circuit SymbolsjojoNovember - 9 - 20110 CommentIn 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 SymbolsThe 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 WiresElectronic ComponentCircuit SymbolDescription

WireWire Circuit SymbolUsed to connect one component to another.

Wires JoinedWires 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 WiresWires Not Joined Circuit SymbolWhen 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 SuppliesElectronic ComponentCircuit SymbolDescription

CellCell Circuit Symbol Used to provide a supply for a circuit.

BatteryBattery Circuit SymbolA 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 SupplyDC Supply Circuit SymbolUsed as a DC power supply, that is, the current will always flow in one direction.

AC SupplyAC Supply Circuit SymbolUsed as AC power supply, that is, the current will keep alternating directions.

FuseFuse Circuit SymbolUsed 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.

TransformerTransformer 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/GroundEarth Circuit SymbolUsed 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.

ResistorElectronic ComponentCircuit SymbolDescription

Resistor Resistor Circuit SymbolA resistor is used to restrict the amount of current flow through a device. Abbreviated as R.

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

PotentiometerPotentiometer Circuit SymbolA 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.

PresetPreset Circuit SymbolPresets 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.

CapacitorElectronic ComponentCircuit SymbolDescription

CapacitorCapacitor Circuit SymbolCapacitor 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 - PolarizedCapacitor-Polarised Circuit SymbolCapacitor can be used in a timer circuit by adding a resistor.

Variable CapacitorVariable Capacitor Circuit SymbolUsed 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.

DiodeElectronic ComponentCircuit SymbolDescription

DiodeDiode Circuit SymbolA diode is used to allow electric current to flow in only one direction. Abbreviated as D.

Light Emitting Diode (LED)LED Circuit SymbolLED is used to emit light when a current is passed through the device. It is abbreviated as LED.

Zener DiodeZener Diode Circuit SymbolAfter a breakdown voltage, the device allows current to flow in the reverse direction as well. It is abbreviated as Z.

Photo DiodePhoto Diode Circuit SymbolPhotodiode works as a photo-detector and converts light into its corresponding voltage or current.

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

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

TransistorElectronic ComponentCircuit SymbolDescription

NPN TransistorTransistor 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 TransistorTransistor 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.

PhototransistorPhototransistor 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 TransistorField Effect Transistor Circuit SymbolLike 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 FETn-channel Junction Field Effect Transistor (JFET) Circuit SymbolThe 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 FETp-channel Junction Field Effect Transistor (FET) Circuit SymbolP-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 FETGiven BelowAbbreviated 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 MOSFETe-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 MOSFETd-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 GatesGateStandard SymbolIEC SymbolDescription

AND GateAND GATE SymbolAND 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 GateNAND Gate SymbolNAND Gate IEC SymbolShort 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 GateOR Gate SymbolOR 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 GateNOR Gate SymbolNOR 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 GateEX-OR Gate SymbolEX-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 GateEX-NOR Gate SymbolEX-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 GateNOT Gate SymbolNOT 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.

MetersElectronic ComponentCircuit SymbolDescription

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

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

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

OhmmeterOhmmeter Circuit Symbol Resistance of the circuit is measured using an Ohmmeter.

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

SensorsElectronic ComponentCircuit SymbolDescription

Light Dependent Resistor (LDR)LDR Circuit SymbolIt 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.

ThermistorThermistor Circuit SymbolInstead of directly measuring the light, a thermistor senses the heat content and converts it into resistance. Abbreviated as TH.

SwitchesElectronic ComponentCircuit SymbolDescription

Push SwitchPush Switch Circuit Symbol This is an ordinary switch that passes current only upon pressing.

Push to Break SwitchPush 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 SwitchOn 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 Switch2-Way Switch (SPDT) Circuit SymbolAlso 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 SwitchDual On-Off Switch (DPST) Circuit SymbolAbbreviated 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 SwitchDPDT Circuit SymbolAbbreviated as DPDT. The switch uses a central OFF position and is applied as reversing switch for motors.

RelayRelay 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 DevicesElectronic ComponentCircuit SymbolDescription

MicrophoneMicrophone Circuit SymbolThis device is used for converting sound to its corresponding electrical energy. Abbreviated as MIC.

EarphoneEarphone Circuit SymbolDoes the reverse process of microphone and converts electrical energy into sound.

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

Piezo-TransducerPiezoTransducer Circuit SymbolIt is a transducer that converts electrical energy into sound.

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

AerialAerial Circuit SymbolThis device is used to transmit/receive signals. Abbreviated as AE.

Output DevicesElectronic ComponentCircuit SymbolDescription

Lighting LampLamp Circuit SymbolThis is used to provide light for the output.

Indicator LampLamp Indiator Circuit SymbolUsed to convert electrical energy into light. The best example is the warning light on a car dashboard.

HeaterHeater Circuit SymbolThis transducer is used to change electrical energy into heat.

InductorInductor Circuit SymbolInductor 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.

MotorMotor Circuit SymbolThis device is used to convert electrical energy into mechanical energy. Can be used as a generator as well. Abbreviated as M.

BellBell Circuit SymbolUsed to produce a sound as the output, according to the electrical energy produced as the input.

BuzzerBuzzer Circuit SymbolIt is used to produce an output sound corresponding to the electrical energy in the input.