Category Electricity

          Electrons, as we know, are negatively charged subatomic particles. They are very important because of their role in various physical phenomena such as electricity, magnetism, etc.

           The history of electrons dates back to 1838, when Richard Laming put forth the concept of an indivisible quantity of electric charge to explain the chemical properties of atoms. Years later, in 1891, Irish physicist George Johnstone Stoney named this charge ‘electron’. Six years after that, British physicist J.J. Thomson identified the particle. The word ‘electron’ is thought to be a combination of the words ‘electric’ and ‘ion’.

           Inside the atom, electrons are in constant motion, revolving around the nucleus.

           They possess a certain amount of energy to maintain distance from the oppositely charged protons inside the nucleus.

         A proton is the positively charged subatomic particle located inside a nucleus.

         Protons are important because it is their number that determines the element (of which the atom is part) and its chemical properties.

         To put it simply, the number of protons in an atom, or the atomic number, defines the type of an atom. Thus an oxygen atom differs from a helium atom on the basis of its atomic number. That number is denoted by the letter ‘Z’.

         The word ‘proton’ was derived from a Greek word meaning ‘first’. It was named by Ernest Rutherford in 1920. One or more protons are present in every nucleus. Together, protons and neutrons form what is known as nucleons.

         Further, protons are made up of invisible particles called ‘quarks’. There is a strong nuclear force that binds these quarks with each other. It is also the same force that primarily contributes to the mass of the proton, rather than the quarks themselves.

        Electric charge is the physical property of matter.

        There are two types of electric charges: positive and negative. Like charges (positive and positive, for example) repel, and unlike charges (positive and negative) attract. The most common charge carriers are the positively charged proton and the negatively charged electron. An object is negatively charged if it has an excess of electrons.

        As per the International System of Units (SI), the unit of electric charge is coulomb, which is equivalent to about 6.242×1018 e. In electrical engineering, the unit is seen as ampere-hour (Ah), and, in chemistry, it is common to use the elementary charge (e) as a unit.

        By convention, the charge of an electron is -1, while that of a proton is +1. The quantity of electric charge can be measured with an electrometer.

        The study of charged particles, and how their interactions are mediated by photons, is called quantum electrodynamics. 

        The wind is a major source of renewable energy that is also useful to generate power. You must have seen windmills in real life, or on television. They are set up on farms for power generation.

        Although they look like fans, windmills work in just the opposite way. In fans, electricity is used to make wind, but in windmills, wind is used to make electricity.

        Let’s see how they work. When the wind blows, it turns the blades of the windmill. This in turn, spins a generator inside, and produces electricity.

         A single windmill can generate only a small amount of electricity. Hence, power companies build wind farms with a large number of wind turbines.

        In many countries including Denmark and Portugal, wind power contributes largely to power production.

        Yet another form of energy comes from ocean tides, which again, can be used to produce electricity. Just like wind turbines, there are tidal turbines too. They are turned by ocean currents. The spinning turbines are connected to devices that generate electricity.

         Here again, the process and products are safe, as there are no harmful emissions made.

As the name suggests, solar power plants use sunlight for power production. There are two different technologies used for solar power production these days- using photovoltaic plants and solar thermal systems.

Photovoltaic cells, or PV cells, produce electric current when exposed to light. They are also called solar cells. They contain silicon, a naturally occurring element found in sand. When sunlight hit silicon, there happens a chemical reaction. As a result, electrons move, and electric current is produced. A group of PV or solar cells create a solar panel. A number of solar panels form a solar array, and they generate solar energy.

In solar thermal systems, sunlight is collected and concentrated to produce high temperature heat that is needed to generate electricity. All the systems have solar energy collectors with two components – a ‘reflector’ that captures and focus sunlight onto the ‘receiver’. In the system here, a heat transfer liquid is heated and circulated in the receiver. It is used to produce steam. The steam is then converted to mechanical energy in a turbine, which powers a generator to produce electricity.

          Electric power transmission means the transfer of electric power from one place to another in large quantities.

           Typically, this happens between a power plant and a substation situated near a populated area. A substation is where voltage is transformed from high to low or vice versa using transformers. When power is transmitted from substations to consumers, the process is called power distribution. Normally, transmission takes place at very high voltage, like 110 kV or above. This is, because of the large amount of power involved in this.

            Over long distances, electricity is transmitted through overhead power transmission lines. But in places that are environmentally sensitive, or where there is very high population, transmission takes place underground. They have high installation cost and operational limitations, yet their maintenance cost is lower.

               The network of power stations, transmission lines, and substations is together known as a transmission grid. 

        From the moment power is generated in a plant, it goes through various stages before reaching our homes.

         Let’s see how power travels. From the electricity generating plants, current is sent through transformers to increase the voltage, so that it can be pushed longer distances.

         Electric power then reaches a substation. Here, the voltage gets lowered, so that it could be sent to smaller power lines.

         From there, it travels through various distribution lines, and reaches your neighbourhood where smaller transformers reduce the voltage, so that you can take safe power to your homes.

        From the transformer, power is carried through service drops, or smaller overhead electrical lines to your homes. It also passes through the ‘meter’ installed in the house that can measure how much power is used by the family.

        The current moves straight to the service panel, where fuses protect the wires inside the house from overloading. Keep in mind that children should never touch this panel!

         It is from here that power finally moves to the switches and outlets all over the house.

       Overhead power lines are structures for electric power transmission and distribution across large distances. They also make the cheapest method for transmitting power.

         In usual cases, overhead power lines have one or more conductors suspended by towers. One of the major duties of these power lines is to maintain enough space or clearance between these energized conductors and the ground, in order to avoid danger.

           These days, power lines can be operated at voltages of 765,000 volts or even more, between conductors. Depending on their range of voltages, overhead power lines can be classified as low voltage, medium voltage, high voltage, extra high voltage, and ultra high voltage.

              However, these power lines are extremely dangerous, and one has to keep a safe distance from them. Unlike household power cords, overhead power lines are not insulated. Even if it looks like insulation, it might be a weatherproofing material. 

       A transformer is an electrical device that transforms electricity from high to low voltage and vice versa. It is an important component for power transmission. Let’s get to know why.

       We saw the process through which electric power reaches our homes. When electricity travels from a power plant, it comes in a very high voltage. This is because the voltage from the plant is ‘stepped up’ by transformers before they are transmitted.

       The voltage has to be increased because electric power has to travel very long distances, and that too, with minimal loss of energy. We should know that energy is lost in the process of power transmission. But if the voltage is high, energy loss would be low.    

        But do our homes need this kind of voltage? Absolutely not! Before the power reaches houses, the voltage has to be lowered, or stepped down. This is where transformers again become important. They step down voltage from high to low. 

         Electric meters are devices that we commonly see in houses and offices. They are used to measure the total electrical energy consumed by the appliances in a house or office. The devices are installed by the electric power company that supplies electricity.

          If you take a close look at these meters, you can see a few digits. They denote the number of units of electricity that has been consumed so far. Our electricity bill depends totally on this reading.

          There are different types of electric meters available in the market. One is the electro-mechanical meter, which is most commonly used in our country. It has a magnetic metallic disc attached, which rotates, depending on the power passing through it. The rate of this rotation decides the reading on the meter.

          Then there are electronic meters that are popular in cities. In these, readings appear digitally on the display fixed on the meter.

          The newest in this league is the smart meter. They are electronic meters, but they have an added advantage. These smart meters are connected back to the utility (which provides us electricity) through the internet. Hence, no official will have to come in person and take the readings. The readings are sent through the internet, which makes the job easier.