Electricity - Charge Difference
Electricity is described as the flow of charge. This charge flow is caused by the atoms, and the subatomic particles that make them - electrons, protons and neutrons. Neutrons, having neutral charges, do not contribute to electricity. The main driver is electrons, which have a negative charge and can move from atom to atom. These negatively charged particles always travel towards areas of high positive charge (or protons) and away from negative charge (other electrons). As they flow, the kinetic energy from the electrons is electricity. This flow of charge is called Current.
Conductivity
Materials have a property called conductivity, which refers to how easily a current (flow of electrons) can pass through them.
Conductors: Easy Electron Flow
Most metals are conductors. The way they conduct is due to their molecular lattice structure, but is irrelevant to Systems Engineering. All that matters is that they are conductive, and they are good conductors. Some other non-metallic materials are also conductive, such as:
- Some non-metals e.g. graphite.
- Liquids with dissolved salts
- Plasma (ionised gases) e.g. lightning, neon signs.
Insulators: Difficult Electron Flow
A majority of non-metals are not conductive i.e. are insulators. Examples include wood, rubber, glass. Another notable conductor is pure water, i.e. not salty water. Air is also a pretty good insulator, which is why electrical circuits get broken when a wire is cut.
Electrical Circuits
In order to harness current to do work, an electrical circuit is required. An electrical circuit contains , in simplest terms:
- A closed loop of conductive materials, which is the path
- A power supply, consisting of many charged particles which can travel through the circuit.
- A load, to convert the electrical energy into another form, i.e. a lightbulb is a load that converts electricity to light energy.
