Electricity is the set of physical effects caused by the presence and movement of electric charge. In physics these effects are described by electromagnetism, one of the fundamental interactions of nature. They include static attraction and repulsion, electric current, lightning, and the generation of magnetic fields. In everyday use, "electricity" also means electrical energy supplied through wires. That form of energy can be converted easily into light, heat, motion and information, which made it one of the defining technologies of the modern world.
Physical basis
Electricity comes from electric charge, a property of some subatomic particles. The electron has a negative charge and the proton has an equal positive charge. Since the 2019 redefinition of SI units, the size of that elementary charge is fixed at exactly 1.602176634 × 10⁻¹⁹ coulombs. Like charges repel and unlike charges attract. Coulomb's law describes this force: it grows with the product of the two charges and falls off with the square of the distance between them. An ordinary atom has equal numbers of protons and electrons, so it is electrically neutral. If it gains or loses electrons it becomes an ion.
When charges are separated, an electric potential difference, or voltage, appears between them, measured in volts. When charges flow through a material, they form an electric current, measured in amperes. In metals the moving charges are mostly free electrons. In electrolytes and plasmas they are ions. How much a material opposes current is called its resistance, measured in ohms. Ohm's law gives the relationship for many conductors: voltage equals current times resistance. Electrical power is voltage multiplied by current and is measured in watts.
Materials fall into three broad groups by how they conduct electricity. Conductors, such as copper and aluminium, carry current easily. Insulators, such as glass and rubber, barely carry it at all. Semiconductors have a conductivity that can be precisely controlled. Moving charges produce magnetic fields, and changing magnetic fields produce electric fields. James Clerk Maxwell unified these effects in the 1860s. His equations showed that light is an electromagnetic wave.
History of discovery
People in ancient Greece noticed that rubbed amber attracts light objects, and the word "electricity" comes from the Greek ēlektron, meaning amber. Systematic study began with the English physician William Gilbert. In De Magnete (1600) he separated the amber effect from magnetism and coined the Latin term electricus. In the 18th century, experimenters built friction machines and the Leyden jar, an early device for storing charge. Benjamin Franklin argued that lightning is electrical in nature and introduced the terms "positive" and "negative" charge.
Luigi Galvani's experiments with frog legs in the late 18th century set off a debate with Alessandro Volta. Volta concluded that the effect came from contact between two different metals in a moist medium. In 1800 he built the voltaic pile, a stack of zinc and copper discs separated by brine-soaked cloth. It was the first battery and the first source of steady current, showing that a chemical reaction could produce continuous electricity. In 1820 Hans Christian Ørsted found that a current deflects a compass needle, and André-Marie Ampère quickly worked out the mathematics of forces between currents. Georg Ohm published his law of resistance in 1827.
The decisive step came in 1831, when Michael Faraday discovered electromagnetic induction: moving a magnet near a coil of wire induces a current in it. Induction is the working principle behind the electric generator and the transformer. Faraday had already shown electromagnetic rotation in 1821, the forerunner of the electric motor. In 1897 J. J. Thomson identified the electron, giving electric current a particle-level explanation.
Electrification
Electricity became practical technology in the 19th century. The electric telegraph appeared in the 1830s and 1840s. Thomas Edison produced a commercially viable incandescent lamp in 1879. In September 1882 he opened the Pearl Street Station in lower Manhattan, an early central power station that sent direct current (DC) to nearby customers. DC voltage could not easily be changed, so stations had to sit close to the people they served. Alternating current (AC) could be stepped up and down with transformers, which made transmission over long distances efficient. AC was promoted by Nikola Tesla and George Westinghouse, and it won the so-called "war of the currents" in the late 1880s and 1890s.
Electrification transformed factories during the second phase of the Industrial Revolution. Individual electric motors replaced the central steam engine and its line shafts. Electric light, streetcars, household appliances, radio and later the computer and the Internet all depend on a reliable electricity supply.
Generation and distribution
Most electricity is produced by generators that turn mechanical rotation into current through induction. Steam turbines are heated by burning fossil fuels or by nuclear fission. Water turbines and wind turbines are driven directly. Photovoltaic solar cells work differently: they convert light straight into current using semiconductor junctions, with no moving parts. Power stations feed an electrical grid, where high-voltage transmission lines cut resistive losses and transformers lower the voltage for distribution. Public supply systems typically run AC at 50 or 60 hertz, depending on the region. Supply and demand have to be balanced continuously.
According to the energy think tank Ember, coal was still the largest single source of electricity worldwide in 2025, at about 33%. In the same year, renewable sources together (hydropower, wind, solar and others) reached about 34%, passing coal for the first time in roughly a century. Solar and wind together supplied about 17% of global generation and nuclear about 9%. Fossil fuels supplied about 57%. Power generation is a major source of greenhouse gas emissions, so how electricity is produced is central to responses to climate change. Grid-scale batteries and other energy storage are being added quickly to balance variable solar and wind output.
Electronics and information
Electricity carries information as well as energy. Vacuum tubes, and after 1947 the transistor, made it possible to switch and amplify signals with electrical control. The integrated circuit packs billions of transistors onto a single chip. It is the basis of computing, telecommunications and digital media, and the field of electronics grew out of these technologies.
Electricity in nature and living organisms
Lightning is a large electrostatic discharge between clouds or between a cloud and the ground. Living cells keep a voltage across their membranes by controlling the flow of ions. Nerve impulses in the brain and body, and the beating of the heart, depend on these bioelectric signals. Some fish, including the electric eel, produce strong discharges with specialised organs. In medicine, electrical signals from the body are recorded in electrocardiography and electroencephalography. Devices such as defibrillators and pacemakers deliver controlled currents to the body. Current passing through the body can injure tissue and disturb heart rhythm, which is why electrical installations follow insulation, grounding and protection standards.
References
- Who Invented Electricity? The Truth Behind Franklin, Tesla, and Edison - Nibble Blognibble-app.com
- When and Who Invented Electricity?electricians-london.co.uk
- Who Invented electricity?electricalcuriosity.com
- History of Electricity - IERinstituteforenergyresearch.org
- Electric power industryen.wikipedia.org
- The History of Electricity - Compact Historiescompacthistories.com
- Global Electricity Review 2026 - Ember Energyember-energy.org
- Electricity demand and supply trends - Ember Energyember-energy.org
- Clean energy pushes fossil-fuel power into reverse for ‘first time ever’ - Carbon Briefcarbonbrief.org