Electrical Terms Explained.

Ampère (A): International unit of measurement of the intensity of electric current.

Alternate current (AC): Electrical current flow, variable in time, both as intensity that direction. Reaches a maximum positive value and a maximum negative value passing from zero.

Direct current (DC): Flow of electrical current, constant in time, both in intensity as that direction.

Ground connection (PE): Point of connection of the electric masses intended to be connected physically to the earth. The correct operation avoids the risk of electric shock.

Diode: Non-linear passive electronic component, whose function is to allow the passage of current flow in one direction only and lock it in the opposite direction.

Ohm (Ω): International unit of electrical resistance.

Current rectifier: It is a device consisting of diodes, capable of converting an AC voltage into a DC voltage.


Electrical resistance: Capacity of a conductor to oppose the passage of electric current generating heat.

Transil (TVS = Trans Voltage Suppressor): Electrical component belonging to the category of non-linear transient suppressors. Has a behaviour similar to a Zener diode, but unlike the latter, serves to protect electronic circuits against overvoltage spikes fast and destructive.

Varistor (VDR = Voltage Dependent resistor): Non-linear electronic component used to protect electronic circuitry from overvoltage spikes fast and destructive.

Its behaviour can be compared to a resistor (non-linear) that if it is exceeded the voltage for which it is designed, rapidly lowers its internal resistance so that the spike is strongly attenuated.

Volt (V): International unit of electric potential, and of the potential difference between two points of a conductor or an electric component.

Watt (W): International unit of power.


V : Voltage Volt (V)

R : Resistance Ohm (Ω)

I : Current intensity Ampere (A)

P : Power Watt (W)