Electricity & its flow: simple explanation

Electricity powers everything around us, from a mobile charger to giant industrial machines. Yet, many people find electrical terms confusing. This guide explains electricity simply and practically, using analogies, real-world examples, and clear transitions, so that even beginners can understand how power is generated, distributed, and used in homes and industries.

What Exactly Is Electricity?

Electricity is nothing but the flow of electrons through a conductor.

Consider it as water moving through a pipe. When electrons flow, electricity is created.

Electrons = water droplets ,Wire = water pipe ,Flow speed = current ,Pressure = voltage

This simple water analogy makes all electrical concepts clearer, with the difference that :

Electrons flow from negative(-ve) to positive(+ve). Electrons are attracted to the positive terminal due to its negative charge.
conventional current flow from positive(+ve) to negative(-ve).

Voltage & Current: The Most Important Relationship

Voltage (V) is the force or pressure pushing electrons.
Current (A) is the flow of electrons caused by that force.

A high voltage means a strong pushing force, while current indicates the amount of electricity actually moving through the wire.

AC vs DC — The Core Difference

Comparison of DC and AC circuits with direction of current flow and voltage waveform graphs.

*aC (Alternating current)*	*dC (Direct current)*
AC keeps changing direction rapidly -50 times per second (50Hz in India)	DC flows in one fixed direction, just like water flowing in a straight channel.
ideal for: Long-distance transmission, Household appliances, Industrial equipment	Perfect for: Batteries, Mobiles, Laptops, LED lights, EVs
power source: power plants(Thermal, solar, hydro,nuclear,geothermal) wind turbine	power source: Batteries, solar panels, DC adapters, rectifiers
Voltage can be stepped up or down easily by transformers	DC offers a stable voltage, requiring converters for voltage conversion
Frequency 50-60 Hz	Frequency 0 Hz due to steady flow
aC can be converted to DC using rectifiers	DC can be converted to AC using inverters
excellent for long-distance transformation	high losses over long-distance transformation
more dangerous for humans & living things due to changing polarity	Comparatively safer at low voltage

Diagram showing solar panel energy flow with DC to AC conversion through inverter, switchboard, battery, and grid connection.

“That’s why chargers convert AC to DC before your phone receives power.”

Single Phase AC vs Three Phase AC

Waveforms of single-phase and three-phase supply showing voltage, current, and power pulsation differences

*Single Phase (Used in Homes – 215/230V)*	*Three Phase (Used in Industries – 415V)*
1 phase (one live wire + one neutral)	3 phase (three live wires + one neutral optional)
Voltage level 230V-240V	Voltage level 400-415V(line to line),230V(line to neutral)
pulsating power delivery	Smooth & continuous power delivery
suitable for light loads	suitable for heavy loads
Single-pole MCB, RCCB, and stabilisers are used in the circuit	3-pole/4-pole mCB, MCCB, Contactor, overload relays used in the circuit
low starting torque	high starting torque
less stable under load variations	very stable under heavy loads
used in shops, homes for fans, lights, TVs, small pumps & motors, refrigerators, etc	used in industries & commercial plants for elevators, compressors, heavy pumps & motors, CNC machines, Transformers & MCC panels, VFD controlled machinery, etc

How Electricity Reaches Your Home or Industry

Electricity travels a long journey before it reaches your switchboard.

Power Plant – Electricity is generated (usually 11 – 25 kV).
Generator – Produces AC power.
Step-Up Transformer – Voltage increased to 132/220/400 kV.
Transmission Lines – Carry power over long distances.
Grid Substation – Receives high voltage power.
Step-Down Transformer – Voltage reduced (e.g., 400 kV to 132 kV).
Sub-Transmission Lines – Carry power to local areas.
Distribution Substation – Further voltage reduction.
Distribution Transformer – Steps down to 415 V (3-phase) / 230 V (single-phase).
Low Voltage Lines – Supply electricity to streets.
Service Drop – Line from pole to house.
Energy Meter – Measures electricity units.
MCB / ELCB / Main Switch – Protection devices.
Distribution Board – Splits the supply to circuits.
Home Wiring – Internal wiring.
Appliances – Electricity is finally used.

Diagram showing the complete journey of electricity from power generation at a power plant through transformers, transmission lines, substations, distribution network, energy meter, and finally to home appliances

Why Electricity Flows Easily in Conductors

Conductors: Have many free electrons, so electricity flows easily.
Semiconductors: Have a limited number of free electrons; electricity flows only when energy is supplied.
Insulators: Have tightly bound electrons, so electricity cannot flow through them.

In simple words:

Conductors (silver, copper, aluminium) – easy flow
Semiconductors (silicon, germanium) – controlled flow
Insulators (plastic, rubber, glass) – no flow

Basic Electrical Formulas

Ohm’s law is considered a fundamental principle for understanding basic electrical circuits. It states that the electric current through a conductor between two points is directly proportional to the voltage across the two points. The constant of proportionality is called the resistance.

$V=IR\quad {\text{or}}\quad I={\frac {V}{R}}\quad {\text{or}}\quad R={\frac {V}{I}}$

Power Formulas in DC Circuits

P = V x I
P = I² x R
P = V² / R

Power Formulas in Single-Phase AC Circuits

P = V x I x Cos Ф
P = I² x R x Cos Ф
P = V² / R (Cos Ф)

Power Formulas in Three-Phase AC Circuits

P = √3 x V_Lx I_L x Cos Ф
P = 3 x V_Phx I_Ph x Cos Ф
P = 3 x I² x R x Cos Ф
P = 3 (V² / R) x Cos Ф

Where:

P = Power in Watts
V = Voltage in Volts
I = Current in Amperes
R = Resistance in Ohms (Ω)
Cos Ф = Power Factor.

Power factor(Cos Ф) is a measure of electrical efficiency in AC circuits, representing the ratio of real power (kW, useful work done) to apparent power (kVA, total power drawn), and ranges from 0 to 1. A higher power factor (closer to 1) means more efficient power use.

Where AC, DC, Single-Phase & Three-Phase Are Used Together

*Supply Type*	*Voltage*	*Used In*	*Examples*
AC – Single Phase	230V	Homes	Lights, fans, ACs
AC – Three Phase	415V	Industries	Motors, pumps, compressors
DC – Low Voltage	5V–48V	Electronics	Phones, LEDs, laptops
DC – High Voltage	300–800V	EVs, solar systems	Batteries, inverters

What is earthing?

It is the process of an instant discharge of electrical energy into the earth through a low-resistance wire & provides a safe path for leakage or fault current to flow into the ground. This prevents electric shock and protects both humans and equipment.

types of earthing(Physical installation types)

Pipe Earthing: Most efficient & commonly used in homes and buildings; economical and effective in normal soil conditions.
Plate Earthing: Used where soil resistivity is high; suitable for commercial and industrial installations.
Rod Earthing: Used in rocky or hard soil areas; easy to install and requires less space.
Strip / Wire Earthing: Common in substations and large electrical installations for grounding structures.

types of earthing(Functional types)

Neutral Earthing

Neutral earthing means connecting the neutral point of a power system (transformer or generator) directly to the earth.
It is mainly done to stabilise system voltage and control fault current.
Neutral earthing helps protective devices detect earth faults quickly.
Commonly used in power stations, substations, and distribution transformers.

2. Equipment Earthing

Equipment earthing means connecting the metal body of electrical equipment to the earth.
Its main purpose is human safety during insulation failure or leakage current.
It ensures fault current flows to the ground instead of through a person.
Used in home appliances, industrial machines, panels, motors, and enclosures.

Note: Neutral earthing can be called grounding in power systems, but grounding does not always mean neutral earthing.

Diagram comparing an electric system with proper earthing and without earthing, showing fault current path, live wire, neutral wire, and electric shock risk.

Importance of Earthing

Protects people from electric shock.
Ensures the quick operation of MCB and RCCB during faults.
Reduces risk of electrical fire and equipment damage.
Maintains voltage stability in electrical systems.
Protects appliances from lightning and surge effects.

Earthing is achieved by connecting the neutral or non-current-carrying part of the equipment to ground.

Electricity can feel complicated, but when broken into simple ideas, it becomes easier than expected. With practical analogies, everyday examples, and basic formulas, anyone can understand how electricity works in homes, industries, and machines.

Click to understand the difference between earthing & grounding.

Read about Basic Mechanical Components and Their Functions