Electricity

Electricity is a natural phenomenon resulting from one of the most basic properties of matter, electrical charge. Our understanding of electrical principles has developed from a long history of experimentation. Electrical technology, essential to modern society for energy transmission and information processing, is the result of our knowledge about electrical charge at rest and electrical charge in motion.

The basic unit of electric current is the ampere, named for the French physicist Andre Marie Ampere. One ampere equals 1 coulomb of charge drifting past a reference point each second.

Voltage is the ratio of energy stored by a given a quantity of charge. Work must be performed to crowd same-polarity electric charges against their mutual repulsion. This work is stored as electrical potential energy, proportional to voltage. Voltage may also be thought of as electrical pressure.

The unit of voltage is the volt, named for Alessandro Volta. One volt equals one joule for every coulomb of electrical charge accumulated.

Ohm's law defines the relationship between the three variables affecting simple circuit action. According to Ohm's law, current is directly proportional to the net voltage in a circuit and current is inversely proportional to resistance.