Electrical symbols are the visual representation of electronic elements. These symbols help us to understand a specific electronic instrument in an electric circuit. Electrical symbols can be defined by both national and international standards. These symbols only depict the components of electrical circuits and do not define the function of these electrical instruments.

Read on, to know more about electrical symbols, their types, definitions, diagrams, symbols, and what are their uses in a circuit diagram along with some FAQs.

Electrical Symbols

In general, an electrical symbol is a small image that is used to represent an electrical or electronic function or device. They are also called circuit symbols or schematic symbols as they are used in electrical diagrams and schematics.

Types of Electrical Symbols

There are many electrical and circuit symbols that are used internationally around the globe. While they are most of the time standardized, which means that the same electronic symbol is used in different countries but we can still find some international differences in those symbols.

Wire Symbol

A wire symbol is a symbol which denotes a wire present in the electric circuit. There are mainly three types of wire symbols, which are mentioned below.

• Electrical Wire: An electrical wire is a single conducting copper wire which is generally a cylindrical, flexible rod or strand of metal through which electric current flows.

• Connected Wire: These are the wires which stay connected in an electric circuit and through which current flows easily. As they work as a medium for the flow of current from one point to another.

• Not Connected Wire: In circuit diagrams sometimes we come across wires which are not connected but are overlapping one another. To show that a hump is created over a wire. The image below shows a ‘not connected’ wire.

Ground Symbol

It can be defined as a reference point in a circuit which is known as the ground and has a voltage of 0 V. There are three types of ground symbols, which are mentioned below:

• Earth Ground: This symbol depicts a point in an electric circuit that shows the measurement of voltage, a common returning path for electric current or grounding which is a direct connection of the electric circuit to the earth.

• Common Ground: This symbol depicts the source voltage of digital logic ICs, which means that no analog signals are bonded into this reference plane.

• Chassis Ground: It is the metal housing in which some electrical devices are enclosed. The chassis is unusually connected to the green ground wire of power lines present in our homes.

Bulb Symbol

It is a symbol of a light bulb in an electrical circuit. It is used as a source of light and to show the presenceof the electric current in the circuit as it glows when the current is flowing through the circuit.

Resistor Symbol

A resistor is a device which is used to withstand the flow of the current through the circuit. There are five types of resistor symbols in a circuit diagram, all of them are mentioned as follows.

• Resistor: It is a device that is used to resist the flow of current in the electric circuit. Its symbol is depicted below.

• Potentiometer: It is a three-terminal resistor with a sliding or rotating reach that becomes an adjustable voltage divider. It is depicted by the following symbol.

• Variable Resistor or Rheostat: A variable resistor or rheostat is a resistor whose electrical resistance can be adjusted according to the need of the circuit. It is depicted by the following symbol in an electric circuit.

• Thermistor: It is a type of resistor whose resistance is temperature-dependent and works according to it. It is denoted by the symbol shown below.

• Photo-resistor: It is a resistor that is dependent on light and its resistance decreases when it receives light. It is depicted by the following symbol.

Capacitor Symbol

These are the symbols that depict the presence of a capacitor in the circuit. There are mainly three types of capacitor symbols which are listed below.

• Capacitor: It is a device that stores electrical energy in an electric field. The symbol below depicts its presence in the circuit.

 

• Polarized Capacitor: It is a capacitor whose anode is made up of a metal that forms an insulating oxide layer over it through the process of anodization. It is depicted by the following symbol in a circuit diagram.

• Variable Capacitor: It is the type of capacitor whose capacitance can be changed intentionally and repeatedly by mechanical or electrical means. Its symbol is displayed below.

Meter Symbols

There are two types of meter symbols, which are mentioned below.

• Voltmeter:It is a device used to measure the electric potential present in a circuit. It is displayed by the below symbol.

• Ammeter:It is a device that is used to measure the electric current of a circuit. The image below is the ammeter symbol.

• Galvanometer: It is a device which is used to measure the electric current in an electric circuit. The image below shows its symbols in a circuit diagram. As it has two symbols, any of them can be used to represent a galvanometer.

Diode Symbols

There are many types of diode symbols, which are used in a circuit. But only a few which are used commonly in a circuit diagram are mentioned below.

• Simple Diode: It is a semiconductor device that has two terminals that allow current to flow only in one direction. It is displayed by the below symbol

• Zener Diode: It is a diode that allows the flow of current and electricity in reverse direction or we can say it allows current to flow in both directions when it reaches a certain voltage known as Zener voltage. It is displayed by the symbol below.

Transistor Symbols

 

It is a three terminal based semiconductor device which is used to switch on electrical signals in a circuit. There are mainly two types of bipolar transistors, which are used commonly in a circuit. Both of them are mentioned below.

• NPN Transistor: It is a type of transistor in which one P-type material is kept between two N-type materials. Its symbol is displayed in the below image.

• PNP Transistor: It is the type of transistor in which one N-type material is kept between two P-type materials. The symbol is displayed in the below diagram.

Logic Gate Symbol

There are three types of Logic Gate symbols, which are described as well as mentioned below.

• AND or NAND Gate: AND gate gives the value of one only if all the operands are one, and otherwise, it has a value of zero. Whereas, the NAND gate gives the value of zero only if all the operands have a value of one, and otherwise, it has a value of one.

• OR or NOR Gate: OR gate gives the value of one if at least one operand has the value of one, otherwise, it gives the value of zero. Whereas, the NOR gate gives the value of one if all operands have a value of zero and otherwise it has a value of zero.

• XOR or NOT Gate: XOR gate is the digital logic gate that gives a true output when the number of true inputs put in it is odd. Whereas, a NOT gate is a logic gate that carries out logical negation.

• XNOR Gate: It is an exclusive NOR gate which is made up by combining the exclusive NOT gate with the exclusive OR gate.

All the gates are displayed in the below image.

Electrical Symbols Chart

Use of Electrical Symbols

The main use of electrical symbols is for representing electronic devices in the form of symbols in a diagram, by which we can understand them easily in a circuit diagram

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