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
Wire Symbols
Power Supply Symbols
Resistor Symbols
Electronic Component | Circuit Symbol | Description |
Resistor |
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A resistor is used to restrict the amount of current flow through a device. Abbreviated as ‘R’. |
Rheostat |
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A rheostat is used to control the current flow with two contacts. Applicable in controlling lamp brightness, capacitor charge rate, etc. |
Potentiometer |
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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 |
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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 Symols
Electronic Component | Circuit Symbol | Description |
Capacitor |
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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 |
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Capacitor can be used in a timer circuit by adding a resistor. |
Variable Capacitor |
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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 Symbols
Electronic Component | Circuit Symbol | Description |
Diode |
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A diode is used to allow electric current to flow in only one direction. Abbreviated as ‘D’. |
Light Emitting Diode (LED) |
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LED is used to emit light when a current is passed through the device. It is abbreviated as LED. |
Zener Diode |
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After a breakdown voltage, the device allows current to flow in the reverse direction as well. It is abbreviated as ‘Z’. |
Photo Diode |
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Photodiode works as a photo-detector and converts light into its corresponding voltage or current. |
Tunnel Diode |
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Tunnel Diode is known for its high-speed operation due to its application in quantum mechanical effects. |
Schottky Diode |
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The Schottky Diode is known for its large forward voltage drop and hence has great applications in switching circuits. |
Transistor Symbols
Electronic Component | Circuit Symbol | Description |
NPN Transistor |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 Gate Symbols
Meters
Electronic Component | Circuit Symbol | Description |
Voltmeter |
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Voltmeter is used to measure the voltage at a certain point in the circuit. |
Ammeter |
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An Ammeter is used to measure the current that passes through the circuit at a particular point. |
Galvanometer |
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A galvanometer is used to measure very small currents in the order of 1 milli ampere or less. |
Ohmmeter |
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Resistance of the circuit is measured using an Ohmmeter. |
Oscilloscope |
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An oscilloscope is used to measure the voltage and time period of signals along with their shape display. |
Sensor Symbols
Electronic Component | Circuit Symbol | Description |
Light Dependent Resistor (LDR) |
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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 |
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Instead of directly measuring the light, a thermistor senses the heat content and converts it into resistance. Abbreviated as ‘TH’. |
Switch Symbols
Electronic Component | Circuit Symbol | Description |
Push Switch |
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This is an ordinary switch that passes current only upon pressing. |
Push to Break Switch |
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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 |
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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 |
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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 |
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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 |
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Abbreviated as DPDT. The switch uses a central OFF position and is applied as reversing switch for motors. |
Relay |
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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 Device Symbols
Output Devices
5 Comments
The description of the Schottky Diode on this web page seems to be wrong. Doesn’t the Schottky Diode have a LOW resistance and LOW forward voltage drop?
Usefull information on electrical symbols with details
This helps alot with my project im doing but what symbols are input output or controlled deviceses
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