Published by:
Renji Elsa Jacob, M-Tech in Electrical & Electronics Engineering
A great gift of science given to the world is Electricity. It has become a part of our modern lifestyle. We can’t imagine our daily lives without this wonderful gift. Electricity is all around us powering houses, offices, and technologies like our computer, lights, mobile, air conditioners, etc. It gives all the comfort and provides almost all entertainment devices.
To understand electricity, first, we need to understand the fundamentals of electric charges, from where they come, and how do they move.
Electric Charges
An atom has three particles: electron, proton, and neutron. A negatively charged particle is called an electron and a positively charged is called a proton. Both electron and proton carry the same amount of charge but the type of charge varies. Electricity is the flow of charges, to make these charge flow there should be a force called electrostatic force. The force that acts between the electrons and protons is called electrostatic force. Like charges repels each other and unlike charges attract each other.
Conductor vs Insulator
A conductor is a substance that allows electricity to pass through it. This helps in the electron flow so these are used to prepare wires. Examples of the conductor are copper, gold, silver, etc.
Insulators are elements which do not help electron flow and do not help in the flow of electricity. So it is used to make the outer covering of wire and many other safety materials. Examples of the insulators are wood, glass, plastic, etc.
Electric Field
The region around the electric charge in which the electric force act is called an electric field. If the magnitude of the charge is large, then it may create a huge force around the region. The electric field is represented by the symbol “E”. Mathematically we can write E = F/q. The SI unit of the electric field is Newton per coulomb which is equal to a volt per meter.
Generation of Electricity
Electricity is generated from different sources like sun, wind, heat, nuclear elements, and many others. The various method of generating electricity are:
- Thermal Plants: A power station in which heat energy is converted to electric power is called Thermal Power Station.
- Nuclear Plants: Another type of thermal power plants is the Nuclear Plants. Here the heating source is the nuclear reactor.
- Other Renewable Sources: Natural elements like the sun, water, wind, etc. also generate electricity. Example: windmill, solar panels, etc.
Electric current
What is the electric current? It is the core of electricity. Electric current is the motion of the charged particles in the wire. In other words, the continuous flow of electrons in an electric circuit is called electric current. The conducting material consists of a large number of free electrons that move from one atom to another freely.
Unit of Current
Current is the amount of charge passing through a conductor with respect to time. Electric current is denoted with the symbol “I” and “Q” denotes the charge carriers.
Wher Q is the charge and t is the time. The unit of charge is coulomb and time in seconds.
So we can say that 1Ampere of electric current means 1 coulomb of charge passing through a conductor in 1 second.
Direction of electric current
When we connect the battery to a conductor, electrons starting moving from the negative terminal of the battery to the positive terminal of the battery. While the direction of conventional current is from the positive terminal to the negative terminal of the battery.
Based on the flow of electrons, the current is mainly classified into two types:
- Alternating Current
- Direct Current
- Alternating Current: The flow of charges that changes its direction periodically is called alternating current. This type is used for power buildings, offices, etc. The main socket at our home provides the AC power supply.
- Direct Current: The flow of charges in only one direction is called as direct current. In a DC source, electrons move from the negative terminal to the positive terminal of the battery. This is used for most of the low power devices.
Effects of Electric current
The main two effects of electric current are:
- Heat effect – Current is dissipated in the form of heat. If the current flowing is less then heat will be less and if the current flowing is more then heat flow will be more. So we can say that heat dissipated is directly proportional to the current flowing.
This heating effect is used in numerous ways like in electric heater. Here to increase the amount the heat, the resistance is increased. It is also used in electric fuse in which the fuse wire breaks which in turn the circuit breaks when the heat is more.
Example: It is used electrical appliances like electric kettle, electric room heater, etc.
- Magnetic effect – A magnetic field can be observed across a current-carrying wire. We can observe a deflection if we place a compass near an electrically stressed conductor. This shows the presence of a magnetic field.
Example: Electric Bell, TV, Radio, Telephone, etc.
Electrical Safety
Safety is the main concern while working with electricity. We should always be cautious as there is a possibility of an electric shock or burn. When a voltage is applied across two points of the body, a current path is provided and the current produces an electric shock. Electronic components are usually operated at high temperatures and so when we come in contact with them we can suffer skin burns.
Electric shock
An electric shock happens when an electric current passes through our body. Both internal and external tissue can burn and can cause organ damage also. When a point on our body comes in contact with voltage and another point comes in contact with a different voltage or ground then there will be current through our body from one point to the other. The severity of the electric shock depends on the amount of the voltage and the path that the current takes through our body
Effect of electric current on the human body
The nervous system experience an electric shock when an electrical current through the body. The intensity of shock mainly depends on the strength of the current, the duration of contact, and the path taken by the current through the body. In extreme cases, the shock causes the failure of the normal action of the heart and lungs even death.
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