An electric current that reverses its direction periodically. It is supplied in this form by electricity utilities, such as EDF in France.
A measure of electric current.
An electrochemical system used to store electricity.
A material that carries electricity, such as metals.
A mechanical system that allows the adjustment of the wheel speed based on their turning differences.
A unidirectional electric current in which electrons are always moving in the same direction. It is available in this form in batteries or dry cells.
The motion of electrons in a conductor.
Energy (kWh or MJ)
Power that can be spent per unit time, expressed in kilowatt hours (kWh) or mega joules (MJ).
An electrochemical system used to produce electricity from oxygen and hydrogen.
The element with the smallest atom in the universe. It exists as a gas and has an energy density higher than hydrocarbons.
A material that cannot carry electricity, such as air, plastics and glass.
Load flow through the conductor at a given point. It is measured in amperes (A).
Work produced by a force of 1 newton whose application point moves 1 metre in the direction of the force. Symbol J.
A measure of the energy consumed by a device or available for its consumption. For example, one litre of petrol (gasoline) provides 11 kWh, one litre of diesel fuel provides 13 kWh and one kilogram of hydrogen provides 33 kWh.
The force developed per unit time, expressed in kilowatts (kW) or DIN horsepower (PS).
A set of two parallel forces acting in opposite directions and of the same intensity, or a system equivalent to this set, expressed in Newton-metres (Nm).
The measure of electrical voltage.
The power of a system in which an energy of 1 joule is transferred uniformly for 1 second. Symbol W.
To introduce something new, as yet unknown, into an existing phenomenon.
The quantified result achieved by an athlete in each of his or her public performances.