We know that electrical current is the result of the movement of free electrons in a conductive body. Depending on the direction in which these electrons are moving, the current is then referred to as continuous or alternating. Although alternating current and direct current are totally different, they both play an important role in electricity production.

Alternating current

The alternating current (or sinusoidal) is, as its name suggests, an electron flow that flows in one direction and then in another. The electrical charges it carries are equal and the traffic intervals are regular. The frequency of the alternating current is measured in hertz (Hz). It represents the number of direction changes made by the current in one second. In Morocco, as in most European countries, the frequency used is 50 Hz.

The alternating current is generated by an alternator. A turbine driven by energy such as water or wind will create electricity and produce electricity. This is the operating principle of power plants.

Electricity distribution is provided by the high voltage (HV) line network, alternating current is sent to the electrical transformers. From there, the voltage and current are lowered so that the current is distributed in the houses.

Direct current

Unlike alternating current, direct current flows in one direction only, from a negative to a positive terminal. It is produced by the chemical activity of a generator, such as a cell or battery. It can also be produced by a photoelectric effect that is generated by photovoltaic panels. Negative electrons are released and move in the conductive body that makes up the electrical circuit.

In most cases, electricity is transmitted with alternating current. Indeed, the intensity of the latter being limited, the loss of heat and energy (Joule effect) is less important than in direct current.
Over very long distances or in the case of underground or submarine cables, direct current is preferred. Indeed, to transport electricity in DC, only two cables are required, while three cables are required to carry out the transport in AC.