What Is Electricity? Complete Physics & Electric Energy Guide

Read this guide in: English · Português

Electricity is the name given to a set of phenomena that occur because of the imbalance or movement of electric charges — a property inherent to protons and electrons, as well as electrically charged bodies. In electricity, there are electrostatic and electrodynamic phenomena, related to charges at rest and in motion, respectively. When you ask “what is electricity?”, the simple answer is: it is the flow of electric charges that powers everything we plug into a socket.

This guide covers the concept of electricity, the types of electricity, the relationship between electricity and magnetism, the role of electric energy measured in kWh, and how to measure, stabilize and protect your circuit with reliable equipment.

What is electricity?

The concept of electricity is broad, but we can understand it as all the effects that electric charges produce on matter. Electricity is commonly associated with electric current — a movement of charges established when a body is subjected to an electric potential difference.

When you switch on a device, the free electrons in the conductor start moving in an orderly way, transferring electric energy along the circuit. This is the foundation of everything: from the simplest light bulb to the energy meters that record your home’s consumption.

Types of electricity: static and dynamic

The types of electricity can be divided into two broad classes: static electricity and dynamic electricity.

Static electricity

Static electricity is the accumulation of electric charges at rest on the surface of a body. The classic example is rubbing a comb on your hair and watching it attract small pieces of paper: there is no current, but there is an imbalance of charges. It is the same phenomenon you feel as a small shock when touching a door handle on a dry day.

Dynamic electricity (electric current)

Dynamic electricity involves the orderly movement of charges, forming the electric current. This current, measured in amperes, travels through the wires and powers equipment. To measure that energy accurately and reliably, current transformers and energy meters are indispensable — check Yomin Electric’s current transformer range and energy meters.

Electricity and magnetism

Electricity and magnetism are two sides of the same phenomenon: electromagnetism. In 1820, Hans Christian Ørsted discovered that an electric current produces a magnetic field; in 1831, Michael Faraday discovered electromagnetic induction — the principle behind generators, motors and transformers to this day.

It is because of this relationship that a current transformer can step high currents down to safe measurement values — applying exactly the principle of magnetic induction to protect instruments and meters.

Electricity in physics

For anyone studying physics, electricity is one of the pillars of the curriculum — whoever searches “physics electricity” online wants to understand exactly this: electrical phenomena explained by the laws of physics. Electricity in physics appears in electrostatic and electrodynamic phenomena, in Coulomb’s and Ohm’s laws, in the concepts of electric field and potential, and in electric potential energy.

The main quantities of physics, electricity and circuits include:

• Electric charge (Q) — measured in coulombs (C); the fundamental charge of the electron is about 1.6 × 10^-19 C.
• Electric current (i) — measured in amperes (A); i = ΔQ / Δt.
• Electric voltage (U) — measured in volts (V).
• Electric resistance (R) — measured in ohms (Ω); in Ohm’s first law, U = R · i.
• Electric power (P) — measured in watts (W); P = U · i.
• Electric energy (E) — measured in joules (J) or kWh; E = P · Δt.

These electricity formulas are the basis of consumption calculations and sizing for any installation.

Electric energy: what you pay for on your bill

The electric energy consumed by an appliance of power P over an interval Δt is calculated as E = P · Δt. A 5,500 W shower head running for 1 hour consumes 5.5 kWh — and that is exactly what your utility bills you for.

That is why accurate energy measurement is essential: without a reliable energy meter, there is no way to bill, audit or reduce consumption. Smart meters with RS485/MODBUS communication enable real-time monitoring, waste detection and cost reduction — especially in condominiums, industries and commercial buildings. Where voltage fluctuates, a voltage stabilizer protects sensitive equipment.

A brief history of electricity

The first documented observation of electrical phenomena is attributed to the Greek philosopher Thales of Miletus, who noticed that amber, rubbed with leather, attracted small objects. The word amber — elektron in Greek — gave its name to the electron.

• 1744 — Benjamin Franklin demonstrated that lightning is an electrical phenomenon.
• 1796 — Alessandro Volta invented the first battery.
• 1820 — Ørsted discovered the magnetism produced by current.
• 1827 — Georg Ohm established the relationship between voltage, current and resistance.
• 1831 — Faraday discovered electromagnetic induction.
• 1880 — Thomas Edison developed the incandescent lamp.
• 1886 — George Westinghouse and Nikola Tesla promoted alternating current.
• 1905 — Albert Einstein explained the photoelectric effect — the basis of solar panels.

This history turned electricity into something increasingly popular and accessible — and today, into a resource that must be measured and protected in every installation.

How electricity reaches your home

From the generating plant to the socket, electricity travels a long path: generation, high-voltage transmission, substations, distribution and, finally, metering at the “house of electricity” — the exact point where each customer’s consumption is recorded.

Inside the home, the circuit starts at the meter, passes through protection devices and continues through the wiring and sockets to the equipment. The better the quality of every link in that chain — metering, protection and connections — the safer and more efficient the installation.

Electrical safety: protecting people and equipment

Working with electricity demands strict safety rules. In the United States, standards such as NFPA 70E and OSHA regulations define the requirements for safe work on electrical installations: protection against electric shock, proper grounding, lockout/tagout procedures and overcurrent protection.

Components such as fuses, breakers and circuit protection are an essential part of compliance — they interrupt current under abnormal conditions and prevent fires and accidents. Yomin Electric also offers voltage protectors to shield equipment against overvoltages.

Quick exercises about electricity

To fix the concept, test your knowledge:

1. A 5,500 W appliance running for 2 hours consumes how many kWh? Answer: E = 5.5 kW × 2 h = 11 kWh.
2. A wire carries 2 × 10^-14 C every microsecond. What is the current? Answer: i = ΔQ / Δt = 2 × 10^-14 / 10^-6 = 2 × 10^-8 A.
3. Is the electric field a vector or scalar quantity? Answer: Vector; electric potential is scalar.

Final Thoughts

Understanding what electricity is goes far beyond theory: it means knowing how to measure energy, recognize the types of electricity, and protect people and equipment. Whether residential, commercial or industrial, correct metering and protection make all the difference in both your bill and your safety.

Yomin Electric manufactures energy meters, current transformers, stabilizers, protection devices and wiring accessories for projects of every size — view the full meter range or talk to our engineers. Read the Portuguese version: O que é Eletricidade?