What are the Electronic Circuit and Their Symbols?

Electronics is a branch of an engineering, which deals with electronic and electrical circuits like Integrated circuits, Transmitters, and Receiver etc. The electronic circuit is defined as it is a combination of various electronic components that allow the flow of electric current. The electronic components consist of two or more terminals, that are used to connect one component to another component to design a circuit diagram. The electronic components are soldered on circuit boards to make a system. If you want to focus on core side projects like electronics/ electrical, you should know the basic concepts of electronic circuit symbols and their usage. This article gives an overview of electronic circuit symbols with their functionality.

Electronic Circuit Symbols
Electronic Circuit Symbols

Electronic Circuit Symbols

The electronic circuit symbols mainly involve wires, power supplies, resistors, capacitors, diodes, transistors, meters, switches, sensors, logic gates, audio devices, and other components.


A wire is a two terminal, single and flexible material, that allows the flow of power through it. These are mainly used to connect the power supplies to the PCB( Printed Circuit Board) and in between the components. The different types of wires will be as


Wires: A single wire with two terminals will pass the current from one component to another.
Wires Jointed: When two or more wires are connected with each other that is called as wires jointed. The joining or shorted of wires at one point is indicates the “blob”.
Wires not Jointed: In complex circuit diagrams, some wires may not connect with others, in this case, bridging is commonly utilized.

Power Supplies

A Power supply/ power supply unit is an electronic device, that supplies electric energy to an electrical load. The flow of an electric current will be measured in terms of Watts. The function of the power supply is, it converts energy from one form to another according to our requirement. The various types of power supplies are

Power Supplies
Power Supplies

Cell Circuit: Supplies electrical energy from larger terminal (+) positive sign.
Battery Circuit: A Battery is two or more cells, the function of battery circuit is the same as cell circuit.
DC Circuit Symbol: Direct current (DC) always flows in one direction.
AC Circuit Symbol: AC (Alternating Current) flows periodically reverses direction.
Fuse Circuit: The fuse will flow sufficient current and it is used to provide overcurrent protection.
Transformer: It is used to produce AC power supply, energy is transferred in between primary and secondary coils in the form of mutual inductance.
Solar cell: It will convert light energy into electrical energy.
Earth: It supplies the 0V to the circuit that will connect to the earth.
Voltage Source: It will supply voltage to the circuit elements.
Current Source: It will supply current to the circuit elements.
AC Voltage Source: It will supply the AC voltage to the circuit elements.
Controlled Voltage Source: It generates controlled voltage to the circuit elements.
Controlled Current Source: It generates controlled current to the circuit elements.



A Resistor is a passive element that opposes current flow in a circuit. It is a two-terminal element, dissipates its energy in the form of heat. The resistor will damage due to the overflow of electric current through it. Resistance is measured in units of ohms and resistance, resistor color code calculator is used to calculate the value of the resistor according to its colors.


Resistor: It is a two terminal component, that restricts the flow of current.
Rheostat: It is a two terminal component, that is used to adjust the flow of current.
Potentiometer: Potentiometer is a three-terminal component that will adjust the voltage flow in the circuit.
Preset: Preset is a low-cost adjustable resistor that operates by using small tools like Screwdrivers.


A Capacitor generally referred to as a condenser, it is a two-terminal passive component that will capable of storing energy in the form of electricity. These are the rechargeable batteries mainly used in power supply. In the capacitors, electrical plates differ by a dielectric medium and these are acts like a filter that allows only AC signals and blocks DC Signals. The capacitors are classified into various types that are discussed below


Capacitor: A capacitor is used to store the energy in electrical form.
Polarized Capacitor: Stores electrical energy these must be a one way round.
Variable Capacitor: These capacitors are used to control the capacitance by adjusting the Knob.
Trimmer Capacitor: These capacitors are used to control the capacitance by using Screwdriver or similar tools.


A Diode is an electronic component with two terminals that are anode and cathode. It allows electron current flow from cathode to anode but it blocks another direction. The diode will have low resistance in one direction and high resistance in another direction. The diodes are classified into various types that are discussed below


Diode: A diode allows the current flow in one direction.
Light Emitting Diode: It will emit the light when the electric current flows through it.
Zener Diode: It will allow a constant electric current after the breakdown voltage.
Photo Diode: Photodiode will convert light into respective current or voltage.
Tunnel Diode: Tunnel diode is used for very high-speed operations.
Schottky Diode: Schottky diode is for forwarding low voltage drop.


The transistors are invented in 1947 at Bell Laboratories to replace vacuum tubes, that it will control the flow of current and voltage in the circuits. It is a three terminal device and amplifies the current, transistors plays an important role in all modern electronics.


NPN transistor: A P-type doped semiconductor material is placed in between two N-type semiconductor materials. The terminals are the emitter, base, and collector.
PNP transistor: A N-type doped semiconductor material is placed in between two P-type semiconductor materials. The terminals are an emitter, base, and collector.
Phototransistor: It is similar to bipolar transistors, but it converts light to current.
Field Effect Transistor: FET controls the conductivity with the help of an electric field.
N-channel JFET: The Junction Field Effect Transistors are simple of FET for switching.
P-channel JFET: P-type semiconductor is placed in between N-type junctions.
Enhancement MOSFET: Similar to DMOSFET but an absence of conducting channel.
Depletion MOSFET: The current flows from source to drain terminal.


A Meter is an instrument used for measuring voltage and current flow in electrical and electronic components. These are used to measure the resistance and capacitance of the electronic components.


Voltmeter: It is used to measure voltage.
Ammeter: It is used to measure current.
Galvanometer: It is used to measure small currents.
Ohmmeter: It is used to measure the electrical resistance of a particular resistor.
Oscilloscope: It is used to measure voltage with respect to time for signals.


A Switch is an electrical/electronic component that will connect electrical circuits when the switch is closed, otherwise, it will break an electrical circuit when the switch is open.


Push switch: It will pass the current flow when the switch is pressed.
Push to break switch: It will block the current flow when the switch is pressed.
Single pole single throw switch (SPST): Simply, it is an ON/OFF switch allows flow only when the switch is in ON.
Single pole double throw switch (SPDT): In this type of switch current flows in two directions.
Double pole single throw switch (DPST): It is a dual SPST switch, mainly used for electrical lines.
Double pole double throw switch (DPDT): It is a dual SPDT switch.
Relay: A relay is a simple electromechanical switch made up of an electromagnet & a set of contacts. These are found hidden in all sorts of devices.

Audio Devices

These devices convert an electric signal into sound signals and vice versa, which will be audible to humans. These are input/output electronic components in the circuit diagram.

Audio Devices
Audio Devices

Microphone: converts sound or noise signal to an electrical signal.
Earphone: converts an electrical signal to a sound signal.
Loudspeaker: converts the electrical signal to sound signal but it will amplify version.
Piezo- transducer: converts flow of electrical energy to sound signal.
Bell converts the electrical signal to sound signal.
Buzzer: converts an electrical signal to sound signal.


Sensors will sense or detect moving objects and devices, it will convert those signals into electrical or optical. For example, a temperature sensor is used sense temperature present in the room. The various types of sensors are


Light-dependent resistor: These sensors will sense light.
Thermistor: These sensors will sense heat or temperature.

Logic Gates

Logic gates are the main building blocks in the digital circuits, logic gates will have two or three inputs and a single output. The output produced by logic gates based on certain logic. Basic Logic gate values represent in binary if we observe their truth tables.

Logic Gates
Logic Gates

AND Gate: The output value is HIGH when two inputs are HIGH.
OR Gate: The output value is HIGH when one of the inputs is HIGH.
NOT Gate: The output is the complement of the input.
NAND Gate: The complement of the AND gate is a NAND gate.
NOR Gate: The complement of the OR gate is a NAND gate.
X-OR Gate: The output is HIGH when an odd number of HIGH occurs in its inputs.
X-NOR Gate: The output is HIGH when an even number of HIGH occurs in its inputs.

Other Components

These are the some of the electronic/electrical components that are utilized in an electronic circuit or electrical circuit design.

Other Components
Other Components

Lighting Lamp: It is a bulb that will glow when certain current flows.
Indicator Lamp: It will convert electricity to light.
Inductor: It will generate a magnetic field when current flows through it.
Antenna: It is used to transmit and Receive the radio signals.

Thus, this is all about electronic circuit symbols. Hope this article gives you a brief information by reading the above article. Furthermore, any queries regarding this article or electronics projects, please share your valuable suggestions by commenting in the comment section below. Here is a question for you, what are active and passive components?


  1. I would like to see a real pcb with external power imput point shown by the silk screen on that very pcb.I want to know what symbols are found there.

    1. Tarun Agarwal says:

      Hi Aaron
      Sorry to inform you that we cannot provide you like that

  2. kesavelu.s says:

    This page is very use full to me for knowing about the basics related to electronic components .I requested you to upload any applications regarded explained above…

    1. Tarun Agarwal says:

      Hi Kesavelu, Thank you for your appreciation.
      For more information on electric components, working, applications and projects please refer to the link.
      For customization of projects please email us on team@elprocus.com

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