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Have you ever wondered how electricity works? Whenever you look at your home power system, you may start to wonder how everything moves through cables and powers up all your appliances. In this article, we'll go through everything you should know about electricity to fully understand how it works. Let's dive right in!
What Is Electricity?
Thanks to Benjamin Franklin, we now use different appliances for different reasons today, and most of these appliances are powered by electricity. From industrial equipment to office equipment and household appliances, almost everything around us today works with electricity. Even some vehicles today are electrically powered. So, it's common to wonder what electricity is.
The first question most people ask is, where does electricity come from? We all know what matter is and that matter is made up of atoms, but what are these atoms? Atoms are the most minor component of all elements. It consists of different electrons and a nucleus, with the electrons surrounding the nucleus.
There are orbits around the nucleus of every atom, and the number of electrons in these orbits is what is used in identifying elements. The number of protons is also used, but these protons are usually within the nucleus. The nucleus comprises neutrons and protons, and their numbers in the nucleus are balanced.
Unlike electrons, neutrons do not possess an electric charge. Electrons are negatively charged, while protons are positively charged, and the number of protons is always equal to that of the electrons. Basically, there's an attractive pull from the protons, which binds the electrons in the orbits around the nucleus.
However, the electrons on the outer part of the orbit are not firmly bound by this force, and they tend to become free. Such electrons are usually referred to as free electrons. The free electrons are the ones that quickly move from one atom to another, thereby leading to the flow of electrons, which is the basis of electricity.
Not all materials can allow electricity to pass through them, and materials that will enable the flow of these electrons are called conductors. In contrast, those that can't let the free flow of electrons flow are called insulators. Matter has atoms with electric charges, which in turn makes the matter itself have these electric charges.
However, some matter has a balanced number of electrons and protons, which balances the negative charge force and positive charge force. This is known as the neutral state of an atom. Static electricity is a term used to describe a case where everything comprises electric charges.
For instance, when you rub a material over another material to create static electricity. The free electrons present on one of the materials are transferred to the other. Therefore, as the electron on one of the materials decreases, it gains more positive charges, and the electron on the other material increases, making it have a negative charge.
Current, Voltage, And Resistance
Here are some of the fundamental terms to know to fully understand how electricity works.
What is current?
This is one of the most standard electrical phenomena, and it's a result of the transfer of free electrons between different atoms. It's worth noting that the features of static electricity are entirely opposite to that of current electricity. Wires comprise different conductors like aluminium or copper, while atoms are made of free electrons that move between different atoms.
This is also the same for the atoms present in metals. As an electron is added to the wire, it attracts a free electron to a proton, causing it to be neutral. This, in turn, pushes the electrons from their orbits to cause a shortage of these electrons. With that, the electrons will be in continuous motion, which is known as electric current. In solid conductors, electric current is described differently, and it's the directional movement of negative to positive electrons between atoms.
On the other hand, liquid conductors and gas conductors involve the flow of electrons and protons in opposite directions. With that said, current simply means the flow of electrons between atoms. However, you should note that electrons and current flow in opposite directions. Electrons flow from negative to positive, while current flows from positive to negative.
The number of electrons that pass through a conductor within a second is used to determine current. The unit for measuring current is in amperes, mostly abbreviated as amps or with the letter "A." Therefore, if you see a current of 1A written anywhere, it means that the current passes through the cross-section of different conductors, and they are 1m apart. Also, the force between each conductor is 2x10-7 Newton per meter. The charge that passes through the conductor during this time is 1 coulomb.
What is voltage?
As discussed above, electric current describes the flow of electrons within a conductor. However, a force pushes these electrons. The current can easily flow through the conductor, and that force is referred to as potential and voltage. Potential is another term for voltage.
For instance, if the first element has more negative charges, it is said to have lower potential. If it has higher positive charges, then it has a higher electrical potential. Another important term is the potential difference, which is basically the difference between two points.
There is also a force responsible for the constant flow of current through the conductor, which is known as the electromotive force. The generation of this force is easy, and it can be from a fuel cell, flashlight battery, or a power generator.
The unit for measuring voltage is volt, abbreviated as "V." It is also used to measure electromotive force and potential. Therefore, 1V can be said to be the force that allows a current of 1A to move through a conductor.
What is resistance?
The next important term to look at is resistance. Many things happen as electrons move from one atom to another in a conductor during the flow of current. There's a resistive force to the flow of electric current through most materials. Moreover, the intensity of these forces varies depending on the material. This is known as resistance. Basically, the resistance of a material increases as the length of the material increases or as the cross-section decreases.
The resistance of a material is generally measured in ohms, which is a Greek letter, omega. Therefore, a material with a one-ohm resistance is said to allow a current of 1A to flow with 1V. The level at which materials allow the flow of electrons is different for each material. Some materials allow electrons to flow freely, while others don't. As mentioned above, those that allow electrons to flow freely are known as conductors, and examples of these conductors are saltwater, sulphuric acid, hydrochloric solution, aluminium, silver, and copper.
On the other hand, some materials do not permit the free flow of electrons, and these materials are called insulators. Examples of these insulators are dry paper, glass, and rubber. In addition to conductors and insulators, there is a third type of material, known as a semiconductor. Semiconductors have the features of both insulators and conductors.
Therefore, they can allow the flow of electrons and, at the same time, also control the flow of these electrons through them. Examples of these semiconductors are germanium, silicon, and carbon. Two main factors influence the resistance of a conductor. They include the following:
- The temperature of the material
- Type of material
Measuring Current, Voltage, And Resistance
Now that you understand each of these terms and their significance in the flow of electricity, we'll look at the various ways to measure them.
How to measure current
Current is measured in ampere, and the instrument that is used for this purpose is called an ammeter or an ampere meter. To measure current, you will first need to connect a light bulb to a battery cell. The current passing through the light bulb can be measured by connecting the negative part of the battery to the positive terminal on the ammeter.
There are specific safety tips that you should know. First, you'll need to estimate the current you want to measure so that you can choose the right ammeter. There are different ammeters, and they all have different measurement limits.
The next thing is to ensure that the negative terminal and positive terminal connections are correct. Lastly, you'll need to ensure that you are not directly connecting the dry cell terminals to the ammeter, as doing this can cause damage to the meter.
How to measure voltage
Voltage is measured in volts, and the instrument used in measuring voltage, potential difference, or electromotive force is the voltmeter. To measure the voltage, you'll first need to connect a light bulb to a battery cell. Keep the voltmeter parallelly wired to the light bulb for accurate measurement.
For this, you'll need to connect the battery's positive terminal to that of the voltmeter and the negative terminal of the battery to that of the voltmeter.
Just like measuring current, there are also a few safety measures that you'll need to take. This includes estimating the voltage you want to measure to help you choose the right voltmeter. Every voltmeter has a limit to the voltage that it can measure. The next thing is to ensure that the terminals are correctly connected.
How to measure resistance
Resistance is measured in ohms, and the instrument for this purpose is a multimeter or a test meter. This instrument can take other measurements, including current and voltage. It can do this because it has been designed to function like an ohmmeter, voltmeter, and ammeter.
To measure resistance using the multimeter, you'll first need to turn the face dial to resistance and touch both terminals against each other so that you can reset the meter range to zero. After that, you can now connect the two terminals to resistance so that you can take its measurement.
How Electricity Actually Works
We have been able to lay a solid foundation for understanding electricity and how you can measure different electrical components. Let us now examine how electricity works in more detail. Remember that electric current can be seen as the ability to do work, and it can be converted to magnetism, power, and heat energy. Therefore, we can classify electric current based on its function, and this includes:
- Heat and power
Heat and power
As the name suggests, electric current makes heat and power. Here's an instance to help you understand better. Nichrome wire that is designed to carry current is also designed with a very high resistance so that it can produce heat. That is why the wires are mainly applied to components of light bulbs, electric irons, toasters, and electric ovens.
Experiments can be performed to properly understand this process, and one of such experiments involves using a calorimeter to measure the quantity of heat in the water. A variac is used to increase the voltage across the wire, and it's then connected to a voltmeter and ammeter for voltage and current measurement, respectively.
After that, the variac scale is set to properly adjust the current and voltage of the nichrome wire. As voltage, time, and current increase, the quantity of heat also increases, and the following equation expresses this:
Heat quantity = 860 x V(voltage) x I(current) x t(interval of time)
This is also known as Joule's law which highlights that heat quantity is dependent on current, voltage, and time interval. On the other hand, Ohm's law states that voltage is the product of resistance and current:
Heat quantity = 860 x I2 x R(resistance) x t
Therefore, it can be said that the quantity of heat ultimately depends on the square of the current multiplied by the time interval and resistance.
As current passes through the nichrome in the water, it is converted to heat energy, which causes the temperature to increase. The electric circuit basically generates heat, and this is also referred to as electric power.
Electric power = Heat quantity
The unit for measuring electric power is Watts-hour, while that of heat quantity is calories.
Electric power = V x I x t
The work done when heat is generated in the circuit is also referred to as power, and this can also be referred to as the work that is done when 1A of electricity flows with 1V. Power is also measured in watts.
Power= Electric power / Time
As current passes through a sodium chloride solution, it causes a chemical reaction known as electrolysis. There are several applications to produce electrolysis today.
Here's an experiment to help you understand better:
The experimental setup involves using platinum plats soaked in molten salt and connected to batteries so that current can pass through the molten salt. This leads to the production of hydrogen bubbles around the negative plate and chlorine bubbles around the positive plate. Sodium chloride consists of positively charged sodium and chloride, which is negatively charged.
As the salt dissolves in water, the bond between the two elements is broken, and they are separated into their respective ions. The molten salt with negative charges is then referred to as cathodes, while that with positive charges is called anodes. Ionisation is the term used to refer to the state of the separated elements, and the solution is called the electrolyte solution. This reaction process is what is popularly referred to as electrolysis.
This is another way electricity is applied today, and it simply involves magnetic lines of flux and a current-carrying wire. The two are applied in electric transformers, tape recorders, and electric motors. To understand how electricity and magnetism work, let us examine what magnetism is. The molecular formula of a magnet is Fe3O4, and the critical feature of every magnet is the ability to attract and firmly hold iron.
Another feature is that magnets work similarly to compass needles, as they also take north and south positions. Materials with this type of feature are called magnets. There are two poles on every magnet: the south and the north poles. In general, the same poles will repel each other while the opposite poles will attract each other.
Placing a magnetic needle close to a current-carrying electric wire will turn the needle in the direction of the current flow. Placing the magnetic needle in a coil with several loops will cause the current to go through the loop in a parallel direction to the lines of flux. It is worth mentioning that this magnetic line of flux also works as an actual magnet, but it lacks magnetic poles.
Placing a current-carrying wire near an iron bar will also cause the bar to move slightly. Also, wrapping the iron with a wire coil will strongly attract the iron. The core is generally soft, which allows it to conduct magnetic lines of force, and as current passes through the coil and core, it becomes instantly magnetised to form electromagnets. This is a principle that is widely applied in many industries today.
Other Important Things To Know About Electricity
Here are some terms that are typically used a lot when it comes to electricity:
This is the term used to describe the route that electrons follow as they flow through different terminals. Closing a circuit will cause the electrons to flow between terminals, and opening it will create a gap within the circuit to prevent the flow of electrons.
Placing any electrical component in the electrical circuit will force the flow of electrons through the circuit. This is usually applied in the generation of light.
Transformers combine different electrical components to induce current flow between different circuits. You can create a transformer by generating an alternating current within a closed circuit before it is transmitted through coils near each other. This will then induce current to different circuits.
The main function of transformers is to help in increasing or decreasing voltages between the different circuits, particularly the primary and secondary circuits.
Capacitors are standard, and you'll find them in most electrical circuits. They work by forcing charges to separate across separate plates after connecting to a power source. This is a build-up in the number of electrons within the electric field. Interrupting the supply of power will cause the release of these charges. The concept of capacitors is very similar to that of batteries, but the only difference is that capacitors can't maintain the supply of power for long.
AC and DC Power
Today, there are two main types of power that people use: alternating current (AC) and Direct Current (DC). The current that flows forwards and backward in a circuit is known as alternating current, and it's the most common type you'll find in most homes today.
On the other hand, the current that flows in a single direction is known as a direct current. These are the type of currents that are supplied by batteries, and the current is applied in portable devices today like phones and laptops. One thing to note is that AC can be converted to DC with the aid of inverters, and this is also applied in most homes today.
Electricians Know Best
While it's great to learn about electricity and understand how it works, it is best to keep this information only to gain knowledge. Working with electricity can be dangerous if performed by a non-professional. So, if you need to get some electrical or solar work done, be sure to contact a licensed electrician or a solar expert for help.