PC Hardware

Understanding Electricity and Electrical Energy

What is electricity? The meaning of the word varies with the user. Electricity to physicists is the primal property of nature, and they call the power delivered at the wall socket and stored in batteries electrical energy. Most people, including computer technicians, are less fussy, often using the term electricity to refer to both:

  • the form of energy associated with moving electrons and protons.

  • the energy made available by the flow of electric charge through a conductor.

For our discussion, we mostly talk about the flow of energy used to run computers-electrical energy-and not worry about the fine points of scientific philosophy.

Some Definitions

For our discussion we employ the following definitions:

  • Electricity: The form of energy associated with charged particles, usually electrons.

  • Electric Charge: When charged particles move in tandem, fields are generated, producing energy.

  • Electrical Circuit: The path taken by an electrical charge.

  • Electric Current: When an electric charge is carried, or flows through a conductor (like wires), it is known as a current. A current-carrying wire is a form of electromagnet. Electric current is also known as electron flow.

  • Power: The rate at which an amount of energy is used to accomplish work. Electrical power is measured in watts, which is determined by multiplying voltage by current.

  • Conductors: Materials that can carry an electrical current. Most conductors are metals.

  • Resistance: A quality of some materials that allows them to slow the speed of an electrical current, producing heat, and sometimes light, in the process.

  • Insulators: Materials that prevent or retard the electrical current of electrons.

  • Ampere: A measurement of current strength, equal to 1 Coulomb per second. Coulomb's Law: two charges will exert equal and opposite forces on each other. Opposite charges attract and like charges repel.

  • Ohm: A unit of electrical resistance. Ohm's Law states that voltage is equal to the product of the current times the resistance, or Voltage = Current x Resistance.

  • Volt: The unit of electromotive force, or potential energy, that when steadily applied against a resistance of 1 ohm, produces a current of 1 ampere.

  • Voltage: The potential energy of a circuit.