The intensity of current is the electrical charge that crosses a section of the conductor in a unit of time. This physical term is very common in university laboratories where the subject is studied. Its academic importance is due to the fact that it is one of the first and most fundamental concepts in electrical studies. The unit of time used for the measurement of electric current through a determined (but conductive) material is the second, therefore, for each second of intensity that is measured, an instantaneous value of the same is determined.

The intensity of current is measured with a galvanometer or Amper (galvanometer calibrated to measure current in conductors) and its unit in the International System of Units is the Ampere denoted by the letter A. The mathematical expression that describes the intensity of electric current is: I = Qt. Electrical conductors must withstand different amounts of load, the more the load is carried, the more resistant the material of which it is composed must be. Silver, copper, aluminum and nickel are elements that are capable of conducting constant and large amounts of electrical energy.

The human body is a conductor of electricity, but strong energy can cause damage to the body. There are several types of electrical current whose intensity is what makes the difference, one is the one used by industries and requires high-resistance conductors, the electrical energy used for domestic use is milder.