How Does Electricity Work?

By Jacquelyn Jeanty

Overview

Basic Properties

There are three main properties that make electricity work: voltage, current and resistance. These properties work together inside a circuit, allowing electricity to move from place to place. Scientists measure voltage in units called volts, current in amps, and resistance in ohms. These three quantities lead to a simple mathematical relation called Ohm’s Law, where a voltage of one volt across a resistance of one ohm gives a current of one amp.

Movement Of Electrons

The process of electricity begins when energy from light, heat, or magnetic fields stimulates an atom's electrons, making them move. Some atoms hold their electrons close to the nucleus and some don't. The atoms with a loose hold on their electrons are best at conducting an electrical current.

Conductors And Insulators

Materials such as silver, gold, copper and aluminum have atoms with loosely-bound electrons, these elements are all metals, and most metals are good conductors of electricity. Materials like glass, air and plastic are called insulators; their electron makeup obstructs the flow of an electric current.

Current And Voltage

In order for electricity to flow in a current, there must be some sort of force or pressure pushing the electrons along. This force is called electromotive force or EMF, which is also called voltage.

Parts Of An Electrical Circuit

A circuit carries this electrical current. It is comprised of an electrical source, a load and conductors such as wires that carry the current between the source and the load. An example of an electrical source is a battery. The load could be nearly any kind of electronic component, from a simple light bulb to complex devices such as smartphones.

Voltage And Current

The amount of electromotive force applied by the source determines how much voltage goes through the circuit. By contrast, current is the quantity of electrons that flow past a point in the circuit in a given amount of time.

Resistance

The last piece of the electricity puzzle has to do with the kind of resistance that is working against the electrical current. For example, if you were to use two heavy-gauge wires in your circuit, more current would flow than if you were to use two thin wires. The thicker wires have less resistance and permit a greater current. It is similar to water flowing through a pipe: A large pipe can carry more water than a narrow one.

Electricity And Power

Electricity carries power, and you can calculate electrical power in watts by multiplying volts by amps. Current flows from the electrical source to the load and back again; the load uses the electrical power to accomplish a useful task, such as lighting a kitchen lamp or running an electric motor in a hybrid car.