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If we want to know better about electricity, want to fix an electrical device, or you are planning to be an electrician? You better know exactly “what is an electrical circuit”. In this post we will not only learn what an electrical circuit is, but everything is related to it. There are a lot of things we need to perfectly understand an electrical circuit.
At first we are going to learn electric circuit definition along with its electronic and electric circuit symbols. The types of electrical circuits are also crucial for us to analyze the circuit and avoid the risks and get better solutions. Here you will also understand the basic and common components of an electric circuit.
If you’re reading this right now, I bet you want to figure out ‘what exactly is electricity and electric circuits’. May it be your own curiosity, homework, paperwork, or even just study it for an upcoming test, you need to know what electricity is and electric circuits.
We know, the explanation itself is too wide and too narrow at the same time. You may find a lot of differences in its theory but at the same time, you may not find the answers you are looking for.
Well, electricity itself is like ‘magic’. You can’t see it with bare eyes but can feel its presence.
Well said, now you have found your best answer here. Here we will learn the basic things about: what is electricity actually, when was it invented, who discovered it, what is an electrical circuit and how it works, and last we will learn electric circuit types and the examples.
What is Electricity
Electricity is called physical phenomena related to the presence of matter which has the property of electric charge. Ages ago, electricity was considered not related to magnetism.
But after Maxwell’s demonstration, both magnetism and electricity are considered as a single phenomenon. The definition of electricity may be:
- Electricity is a form of energy.
- Electricity is a flow of electric charge
- Electricity is the flow of electrons.
If you type ‘what is electricity’, the explanation above is the simple definition of electricity. What is our concern is the electric charge.
This matter can be either positive or negative and produces an electric field. Its movement is called by electric current and is able to produce a magnetic field.
When Was Electricity Invented?
Thomas Edison, an American inventor, did outstanding research, the light bulb in his laboratory in 1879. At the end of the 1880s, small electrical stations were built using Edison’s design in the city of the U.S.
Later after this research, we will know Alessandro Volta, The one who invented the electric circuit.
Alessandro Volta made the invention of the first electric circuit in 1800. He made the statement that connecting the bowls of salt solution with metal strips can produce a steady flow of electricity.
He used a disc of copper, a salt solution soaked cardboard and zinc. His voltaic pile is known as an early battery. By connecting a battery with single copper wire from top to bottom, an electric current flows.
Who Discovered Electricity?
Even electricity is one of the natural phenomena, the one who discovered it needs to be credited. Benjamin Franklin is the first one who discovered electricity with a simple experiment.
He was a passionate researcher and had his golden time on a scientific matter at that time. He had so many great discoveries.
After electrical energy is found by Benjamin Franklin, who is next? The next person is Alessandro Giuseppe Antonio Volta or Alessandro Volta for short.
He was an Italian physicist and the inventor of electricity and power. His most known invention for us is his electric battery.
The voltaic pile is his innovation in 1779-1880. From this invention, we can generate electricity using chemical processes.
What is an Electrical Circuit
When we hear about a circuit, the first thing we imagine is a loop. This loop is connected from head to tail just like a racing circuit. This is the basic idea of “circuitry definition”.
An electric circuit definition is a “circuit” or “path” for the electric current to flow. Not only the path, but an electrical circuit consists of a component which is able to give electrical energy to the circuit, a component which is able to convert the electrical energy to a different form of energy. For the energy supply, we can use a battery and generator.
The component or device that changes the energy to another form of energy can be an electric motor, lamp, heater, device such as a computer and charger, or many more. Don’t forget that we need the “path” or “circuit” which is a conductor, wire, and other transmission line.
For short,
An electric circuit is an interconnection of several electrical components so that the electric charge can flow along in a closed path or closed circuit.
This circuit can be used for various applications.
Electrical circuits contain active and passive electric elements such as resistors, inductors, capacitors, transformers, switches, and many more.
It is very important to learn the parts of electrical circuits, their symbols, and their functions.
If you try to search what is the definition of an electrical circuit, you will find a lot of explanations. But, they actually have the same meaning, just presented in different words. Don’t confuse yourself with such a basic explanation.
An electric circuit is an interconnection of electrical elements
Summary, you can call an electrical circuit as a path or transmission line where an electric current flows through. If the circuit is joined from the start to the end of the line, we call it ‘closed-loop’.
This circuit makes the electric currents able to flow. Otherwise, we call it an ‘open circuit’ where the circuit is not connected at both ends and the electric currents can’t flow.
If you still can’t follow my lead, then to make it super easy, you can check the illustration below. This is the simple electric circuit implementation where we build a flashlight. This simple electric circuit represents basic components of an electric circuit.
In the circuit above, you can find all the three main elements of what form an electrical circuit.
- First, the battery is the element which supplies the circuit
- Second, the lamp is the element which converts the electric energy into another form of energy, in this case is lighting from the light bulb.
- Third, the connection wire which makes a closed-loop circuit. This makes the electric current flow from the battery to the load (lamp) and back to the negative polarity of the battery.
The switch is only an addition to the circuit to control when the lamp is ON or OFF.
If the switch is open then there is no current flowing in the circuit and the lamp is OFF because the circuit is open-circuit. When we close the switch the circuit becomes closed circuit and current is flowing in the circuit then turning ON the lamp.
Now you have understood the term of electrical circuit definition. Keep in mind that an open-circuit can be considered as an electrical circuit, but it can’t make the electric current flow. And it is common sense that you have to draw the circuit in the straight line so you can analyze the circuit better.
How Does Electric Circuit Work?
An electric circuit can work if the circuit is a closed-loop, then the current can flow through the system. One thing to remember, we need the electrons to be able to move throughout the circuit, from the positive pole to the negative pole of a power source.
What is circuit?
An electrical circuit is a path or line where electric current can flow through. The usage of a battery or any power source will produce a force to make the electrons move through end to end of a path.
The simplest example of interconnection is a flashlight circuit. The circuit has three basic elements: a lamp, connecting wires (or conductor wires), and a battery.
If we don’t learn about electrical engineering, we may find it useless.
Now let us apply interconnection to these things. Connecting them all together with the right decision will give us a flashlight.
Electronic and Electric Circuit Symbols
If you are designing, analyzing, or fixing an electrical circuit, you need to know every electronic component along with the electronic symbol in the circuit or every electric circuit symbol you should use. When we are dealing with a circuit, we will most likely deal with its circuit diagram.
Circuit diagram shows the connection of a bunch of electrical components in that circuit. You will absolutely need this to do your job very well. Imagining the circuit without drawing it is very hard, especially for the complex circuit.
The electronic symbols can be divided into:
- Connection wire
- Power supply or power source
- Output device
- Switch (electric or manual)
- Basic components such as resistor, capacitor, and inductor
- Diode
- Transistor
- Audio
- Meter such as voltmeter, ammeter, galvanometer, ohmmeter, power meter, and oscilloscope
- Sensors
- Logic gates
- Integrated circuit
- Operational amplifier
We will learn every symbol above in a brief explanation to make this thing fast.
Connection wire symbols
We will find a lot of intersections of wires in a circuit. Make sure to understand what are the types of intersection here,
Wire
We use this to connect component to component and make an electrical circuit. This is a conductor as a path for the current to flow. The symbol is very simple, just a straight line.
Joined wire
The symbol is the ‘dot’ on the ‘crossroads’. Sometimes it is called a node, since one of the Kirchhoff laws uses this term.
Unjoined wire
In a complex circuit like a circuit which has a feedback sensor, this wire crossing but not joining is a common thing. This crossroad is not connected at all. We can use this curve symbol to show that these wires are not connected. The example on the left is also the same because we don’t use the “dot” but sometimes it can be misread.
Below is the symbol difference of joined wire and unjoined wire.
Power circuit symbols
This element energizes a circuit with either voltage or current.
Cell
The symbol is two lines, the larger one indicates the positive polarity while the smaller one indicates the negative polarity. This element provides electric voltage.
Battery
You should have known this already. The indicator of the polarity is the same with the cell. This element provides electric voltage.
Solar cell or photovoltaic cell
This element converts the solar energy into electrical energy.
DC supply
Supplies the electrical energy in direct current form. Battery also uses this symbol.
AC supply
Supplies the electrical energy in alternating current form.
Fuse
A circuit protection to prevent a blow up if a fault happens. This component can cut the circuit if the current is too high and exceeds the fuse capability.
Transformer
Two wire coils and connected by an iron core. Transformer can step up or step down AC voltage. This component uses the electromagnetic force.
Ground (earthing)
Earth or ground is used to prevent a zap in the circuit when touched.
Below is the symbol of cell, battery, solar cell, dc and ac supply, fuse, transformer, and grounds.
Output devices symbols
This element converts the electrical energy into different forms of energy.
Lamp (lighting and indicator)
A transducer to emit light as an illumination or just a simple indicator.
Heater
A transducer to convert electrical energy into heat.
Motor
A transducer to convert electrical energy into mechanical and kinetic energy.
Bell and buzzer
A transducer to convert electrical energy into sound output.
Below is the symbol of lamp, heater, motor, and bell-buzzer.
Switch symbols
This element is used to control the current flow in the circuit.
NO (Normally Open) switch
A push button which is in a closed state when pressed. It means if we push the button, the current will flow. Do you remember how to turn on and off a flashlight? This is the symbol of it. It may be an electrical switch or analogue switch.
NC (Normally Close) switch
A push button which is in an open state when pressed. It means if we push the button, the current will stop flowing.
Single Pole Single Throw (SPST) switch
The current will flow when the switch is in a close state.
Single Pole Double Throw (SPDT) switch
The two-condition switch which is able to switch the current flow depends on the route.
Double Pole Double Throw (DPDT) switch
This switch can be applied as a reversing switch for a motor.
Relay
The famous electrical switch has so many types of relay.
Below is the symbol for NO and NC switches, SPST, SPDT, DPDT, and relay.
Resistor symbols
This component is used to control the current in the circuit. Resistor provides resistance in the circuit, limiting how much current flows. There are several types of resistor.
Resistor
This prevents the flow of charge to a certain degree.
Rheostat variable resistor
This is used to control the lamp brightness and motor speed.
Potentiometer variable resistor
This variable resistor has 3 ports and one of them is used as a transducer converting position to an electrical signal. Other words, this is used for Analog-to-Digital Converter.
Preset variable resistor (trimmer)
This variable resistor uses a screwdriver to be set to adjust the resistance.
Below is the symbol for resistor, rheostat, potentiometer, and trimmer.
Capacitor symbols
This component is used to provide capacitance in the circuit. There are several types of capacitor.
Nonpolar capacitor
This capacitor doesn’t have polarity and is able to charge electric voltage.
Polar capacitor
The polarity needs to be connected in the correct way and this capacitor has larger capacitance.
Variable capacitor
A variable capacitor as a radio tuner for example.
Trimmer variable capacitor
We can set the capacitance for the capacitor and leave it to work.
Below is the symbol for nonpolar, polar, variable, and trimmer capacitors.
Inductor symbols
The inductor itself has some version of it such as,
Air core inductor
An inductor which has no core or air core.
Iron core inductor
An inductor which has iron as its core.
Ferrite core inductor
An inductor which has ferrite as its core.
Variable core inductor
We can adjust the inductance for this type.
Below is the symbol for air core, iron core, ferrite core, and variable core inductors.
Diode symbols
Diode is a component to prevent the current flow in the opposite direction. There are several types of diode.
Diode
Only allows the current flow in the desired direction.
LED (Light Emitting Diode)
A diode which is able to emit light when the current flowing passes this diode.
Zener diode
This type works just as opposite as the normal diode one and can be used to maintain a fixed voltage.
Photodiode
Diode with high sensitivity to the light.
Below is the symbol for diode, LED, zener diode, and photodiode.
Transistor symbols
You would have known about this one, we will just read the brief explanation about this semiconductor component. You can use this as an amplifier or a switch.
Transistor NPN
Transistor with NPN pin
Transistor PNP
Transistor with PNP pin
Phototransistor
Transistor with high sensitivity to the light.
Audio symbols
This element converts the electrical energy into sound or other way around.
Microphone
Convert sound to electric signals.
Earphone
Device to listen to audio in the form of an electric signal privately.
Loudspeaker
Convert electric signal into audio output to be transmitted in the open air.
Piezo transducer
Converting pressure force to electrical energy.
Amplifier
To amplify electrical signals.
Antenna
To receive or transmit the signals.
Meter symbols
Meters are the instrument to measure any parameter in the electrical circuit.
Voltmeter
Or voltage meter is a tool to measure the electric voltage.
Ammeter
Ammeter is a tool to measure the amperage of electric current.
Galvanometer
A sensitive tool using an armature and a set of magnets.
Ohmmeter
Tool to measure the resistance, measured in ohm. The Ohm itself is very important for us because it is related to the Ohm’s law and basic electrical theory. The ohmmeter symbol is the symbol of Ohm itself.
Oscilloscope
A digital meter which is able to display the waveform as an electrical signal. We can tune the period, measurement scale, and even save the image.
Sensor symbols
This element is capable of receiving energy and converts it into electrical signals.
Light Dependent Resistor (LDR)
A component which is able to convert light into electrical signal or voltage.
Thermistor
A component which is able to convert the temperature into electrical signal or voltage.
Logic gate symbols
Logic gates are used to design a digital sequence program for electronics.
Integrated Circuit (IC)
This type has various applications and is very convenient to use. Usually, it is drawn with a rectangular shape and some ports.
Operational Amplifier
It is also popular with Op-amp and is illustrated with a triangle shape along with three ports: two as inputs and one as output.
Types of Electrical Circuits
If we are talking about the types of electrical circuits, we will find the two very basic types. The first one is a series circuit and the second is a parallel circuit, or you can change the arrangement, it won’t be that important. Their basic difference is how many loops they have in their circuit. You can check the example below, you will understand it faster.
Series circuit
The series circuit has one loop from end-to-end, from the source back to the source. If we cut the wire in any position or remove one of the elements except for the source, that spot is an open circuit and the current will stop flowing.
You can see the example below.
In a series circuit, the current in the circuit will be the same for every element in there. Summary, the current passing through R1 and R2 will be the same value. If we remove one of the resistors then the circuit will be an open-circuit and the current will stop flowing.
That’s the essential thing about series circuits. Another simple example of a series circuit is a flashlight. We just need to connect a battery, switch, and lamp in one path. Once you open the switch then the lamp will die.
Parallel circuit
The parallel circuit has more than one loop for the current to flow. If we cut the wire in any position or remove one of the elements except for the source, that spot is an open circuit but the current can still flow through another loop.
You can see the example below.
In a parallel circuit, the current in the circuit will be the sum of all the current in every loop. The current in each loop depends on the load in that loop. If we remove the R1 then the current through R1 will start flowing through the R2. If we remove the R2 then the current through the R2 will start flowing through R1.
Summary, if we cut one loop then the current will start flowing in another loop as long as there is a loop which is still a close-circuit.
Close circuit
This is the circuit where the circuit is connected end to end and the electric charges are able to move through the system.
This circuit is the same with the flashlight circuit when you turn on the switch.
Open circuit
You will find something strange in this circuit where the circuit is not connected in a specific place. Electric charges are not able to move in this circuit.
The example of this circuit is when you turn off the switch of a flashlight.
Short circuit
A short circuit is a circuit when the current is too large. This can occur if there is no load in a conductor wire connected to a power source.
It is like connecting the positive polarity and negative polarity of a battery with copper wire.
Electric Circuit AC and DC
We will encounter a lot of electric circuits in life applications. The application of an electric circuit will result in a different type of electrical circuit. For starting, the electric circuit types will differ as :
- DC circuit
- AC circuit
The difference between these two is the source of the corresponding electric circuit. If the dc source energizes the circuit, it will be a dc circuit.
On the other hand, an ac circuit happens if the ac source energizes the circuit. Make sure to read both before leaving to advance matters.
Frequently Asked Questions
What is an electrical circuit
What is electricity
What is an electric circuit short definition?
What are the 5 components of an electric circuit?
1. Resistor to provide resistance
2. Inductor to provide inductance
3. Capacitor to provide capacitance
4. Transistor
5. Diode
