Electricity and Electrical energy

We are now an empowered nation with electricity, which has transferred us from the dark to the light. Obviously, you always feel a supreme trigger to know about what electricity and electrical energy are. This article will open the door. Let’s have a stronger idea about these phenomena.

Core knowledge about electricity:

To have a clear idea and an easier understanding, we need to  learn from the atomic level. In an atom, there are three main particles: protons, neutrons, and electrons. The electron is only responsible for producing electricity. Most materials include electrons that are bound to atoms. However, in conductors such as copper or aluminum, some electrons can travel freely. These liberated electrons enable electrical current.

Types of Electricity

1. Static electricity: It occurs when a charge accumulates on the surface of a substance. For example, rubbing a balloon on your hair causes electrons to transfer and cling, causing it to stick to the wall.

2. Current Electricity: The flow of electric charge across a conductor. This is the sort of electricity utilized in households and businesses.

Electric Current:

Electric current (I) is nothing but the flow of charges, and it is defined as the rate of flow of electric charge. Expression: I = Q/T

Where:

I = Current (in amperes, A)

Q = Charge (in coulombs, C)

T = Time (in seconds, s)

In metallic conductors, electrons move from the negative terminal to the positive terminal of a voltage source. However, by historical convention, current is said to flow from positive to negative. That’s why it’s the conventional correct, and its direction is from the positive to the negative terminal of a voltage source.

Voltage:

Voltage is the driving force behind electric charges, as they cannot move without a potential difference between two places, and no current is produced. This potential difference is referred to as voltage (V). The formula is:

V= W/Q

V = Voltage (in volts)

W = Work done or energy transferred (in joules)

Q = Charge (in coulombs)

Resistance:

It is the opposition to the flowing current. Each substance provides a certain amount of resistance (R) to the electron flow. The connection between voltage, current, and resistance is defined by Ohm's Law:

𝑉 = I×R

R is the resistance (measured in ohms, Ω).

Some electrical energy is transformed into heat by resisting the flow of current through insulators, resistors, and even wires.

DC (Direct Current): Current flows in one direction only. For solar systems, computers, and electronics, DC is more reliable.

AC (Alternating Current): Current flows in both directions. Periodically, the flow is reversed. Our homes employ AC because it is more effective at transmitting power over long distances.

Sources of Electricity

Through various means, electricity generation is performed. Some sources are mentioned below:

Mechanical Generators: Mechanical energy is converted into electrical energy using electromagnetic induction.

Chemical Reactions: Through redox reactions, batteries generate electricity.

Solar Cells: Light energy is converted into electrical energy via the photovoltaic effect.

Thermoelectric Generators: Temperature differences are utilized to generate electricity.

Conductors, Insulators, and Semiconductors:

Conductors: Some materials allow electrons to flow freely. For example: Copper, silver, aluminum.

Insulators: Some materials do not allow electron flow. For example: Rubber, plastic, glass.

Semiconductors: Some materials have a conductivity that lies between conductors and insulators. Control of their behavior is possible. For example, Silicon, germanium.

Electric Circuits:

An electric circuit is a closed loop that allows current to flow. It includes:

Power source (Power supply or battery)

Conducting path (Wires)

Load (Bulb, motor)

Control element (Switch)

Series vs Parallel Circuits:

Series Circuit: It provides one path for current. If one component is out of order, the whole circuit stops. 

Parallel Circuit: It provides multiple paths. Each component works independently.

What is Electrical Energy?

We had learning about electricity and current in the previous section, now it our concern is about what electric energy is. Electrical energy is the energy carried by moving electric charges, which happens in a conductor. When an electric potential difference (voltage) is applied, free electrons move through the conductor, create current, and constitute energy transfer.

Definition:

When electrons flow through a circuit for a specific time, the work  

done by the electric current is electrical energy.

Formula:

The standard formula for calculating electrical energy (E) is:

E=P×t

Where:

E = Electrical energy (in joules, J)

P = Power (in watts, W)

t = Time (in seconds, s)

Alternatively, using Ohm's Law and power formulas, energy can also be expressed as:

E=V×I×t

Where:

V = Voltage (in volts)

I = Current (in amperes)

What is Electrical Power?

Electrical power refers to the energy transfer rate of electrical energy by an electric circuit. It is the measurement of how fast energy is used or produced by an electrical component.

Definition:

Electrical power is the amount of energy generated per unit time in an electrical circuit or consumed per unit time.

Formula:

The basic power equation is:

P=V×I

Where:

P = Power (watts)

V = Voltage (volts)

I = Current (amperes)

In resistive circuits, power can also be written as:

P=I²×R or P=V²/R

Where R is resistance in ohms (Ω).

1 kilowatt-hour (kWh) is a common unit used by electricity companies to measure energy usage. For example, if the power of a device is 1000 W and it runs for 1 hour, it consumes 1 kWh of energy.

Types of Electrical Power

Electrical power is broadly categorized into three types, especially in AC systems:

1. Active (Real) Power (P): The actual power consumed by electrical equipment to perform useful work. It is measured in watts (W). Formula is: P=VIcosϕ

Here, ϕ is the phase angle between voltage and current.

 2. Reactive Power (Q): Power stored and released by inductors and capacitors, which does not perform any useful work. Measured in volt-amperes reactive (VAR). Formula is: Q= VIsinϕ

3. Apparent Power (S): The total power supplied to the circuit, which is the combination of active and reactive power and measured in volt-amperes (VA). Formula is: S=VI

Applications of Electrical Energy and Power

Residential: Lights, fans, heaters, air conditioners, and daily appliances use electrical energy.

Industrial: Heavy machinery requires high electrical power.

Transportation: Electric trains, trams, etc., need electrical energy for motion.

Communication Systems: Telecommunications and data centers require large amounts of electrical power.

Electrical Energy Production

Electrical energy is generated from various sources- Conventional: Thermal power plants (coal, gas), hydro power plants, nuclear power plants etc. Non-Conventional: Solar panels, wind turbines, tidal energy, etc. Power is generated in megawatts (MW) or gigawatts (GW) and fed to national grids for distribution.

Losses in Electrical Systems

Energy losses can occur by resistance in wires (I²R losses), imperfect transformers, reactive loads causing phase differences, etc. Minimizing these losses is a required criterion for improving overall system efficiency.

However, electricity is the unseen lifeblood of the modern world; it is more than just a utility. According to science, it is the motion of charged particles that is controlled by the laws of physics. In actuality, it drives almost everything we see, including industries, homes, hospitals, and the internet. In addition to enhancing our understanding, knowing what electricity is and how it functions enables us to use it more sensibly and effectively.