Electrical quantities.

VOLTAGE OR POTENTIAL DIFFERENCE.


The amount of energy that a generator can transfer to electrons depends on its voltage measured in volts (V).
For measure the voltage we normaly use a volmeter with two wires connected in parallel to the element that we are measuring. For example:

MEASURING ELECTRIC CURRENT.

The charge of electrons that flow through the cross-section of a conductor avery second is expressed as:     I= Q/t.
An electric current is measured in amperes (A) in the SI.
One amp is charge of one coulomb which travels through the cross-section of a conductor in a second:  1A=1C/1s
For measure the electric current we use an ammeter connected in series.

OHM'S LAW.

The resistance is the measure of a material's ability to oppose an electric current passing through it. It is measured in ohms and is equal to the voltage divided by  the intensity of the electric current which travels through the material. This operation is called Ohm's Law and it has two more forms:

R= V/I     V=R x I      I= V/R

ELECTRICAL ENERGY AND POWER.

Electrical energy.

The energy that keeps the electrons of a circuit in motion provided y a generator and consume by one or  more loads is called electric tensión.
We can calculate the energy (measure in joules) if an electric current flows at a particular tensión for a certain amount of time: E= V x I x t

Electric power.

It is the amount of energy that it can transform over a certain time of time and is measured in watts (W) or kilowatts (kW). We can calculate the power if an electric current flows at a particular tensión: P= V x I.
Other posible unit of measurement is the kilowatt per hour and can be converted to joules and kilojoules. We can calculate the electrical energy that it consumes over a certain amount of time if we know the poser of a load: E= P x t.