Last night, my apartment faced a major electrical failure, and I had to call an electrician to fix it. As it turned out, it was an issue of faulty wiring that plunged my apartment into darkness. Sitting in the dark waiting for the power to be restored, my roommate and I started to discuss how humans take electricity for granted.
Electricity is as essential for electrical appliances and electronic gadgets, as oxygen is for the living. And yet, we realize the perks of it only when there is a power failure. Such is human nature! Since electric power is making our lives easier day in day out, the least we could do is shed our selfishness and make an effort to understand how it works.
Here goes my attempt to explain concepts of electricity ala layman style.
What is the electric current?
To put it simply, electric current is the flow of charge. Electrons carrying charge across the electric circuit constitutes the electric current. But wait! What are electrons and why are they carrying the charge across the circuit?
To answer this question, we will have to dive deep into the structure of an atom. An atom constitutes proton, neutron, and electron. While protons carry a positive charge and are found in the nucleus of an atom along with neutrally charged neutron, electrons carry a negative charge and can be found revolving around the nucleus in an orbit. The reason why electrons revolve around the nucleus is that they are attracted to the positive charge of protons. Now you know how the term ‘Opposites attract’ was coined!
Wires are generally made of conducting metals like copper that have atoms with electrons revolving in multiple orbits. The electrons in the outermost orbits are easier to be displaced when they come across another negative charge in the circuit because like charges repel each other. So, when a free electron carrying negative charge is introduced to an electric circuit, the electron in the copper atom’s outermost orbit is displaced due to repulsion. Now, this free electron travels to the nearest atom as it is attracted to the positive charge of protons. Once this free electron latches on to an atom, the existing electron of that atom repels the new electron and displaces itself from the orbit. Thus it creates another free electron that will continue the process of displacing more electrons from atoms. This flow of free electrons carrying negative charge forms electric current.
Current is denoted by the symbol I and is measured by the unit called Ampere (A).
What is resistance?
Resistance is defined as the difficulty in passing of current through a material. Unlike conductors, non-conductors have high resistance and thus are not used for making electric wires. However, electric circuits often use a device called resistors that are made of non-conducting materials. Resistors are added in between the circuit to reduce the flow of electric current as some appliances are designed to work on lesser amperes of current.
The symbol of resistance is R and it is inversely proportional to current.
What is voltage?
Remember the external negative charge that is required for the flow of electric current through the wire? This external negative charge comes from the electric field with the positive charge on one side and negative charge on the other. Note that the distance between two sides of the field is such that negative charge can’t directly get attracted to the positive charge on the other side. This distance between two sides of the field causes a potential difference of charge.
If the two sides of this electric field are connected through a closed circuit, then it forms a path for negative charge to travel through the wire to the positive side of the electric field. The potential difference between the two sides of the electric field will form pressure on the negative charge to travel to the positive charge. This pressure is known as voltage.
So greater the voltage, greater will be the pressure on the negative charge to flow, and thus greater will be the electric current. Voltage is denoted as V and is directly proportional to current
The relation between Voltage, Current and Resistance
According to Ohm’s law, voltage, current, and resistance are related by a simple equation of V = IR
V= Voltage
I= Current
R= Resistance
Just like voltage, even current can be calculated by the equation: I = V/R
I hope this blog gave you a good idea of how electricity works and how voltage, current, and resistance are related. Stay tuned to for enlightening articles on different scientific concepts!
