At the beginning of the 18th century it was found out that there exist metals, which conduct the electricity from one physical body to another. Soon after that it became known that electric phenomena are conditioned by that the electricity is represented with the help of two interactive substances. Their properties were denoted by the notion ‘charge’, distinguishing positive and negative charge of bodies. The given substances are divided during the rubbing of bodies of each other that cause electrization of these bodies. The electrization is accumulation of charge of one type on the body. Besides, charges of one type have the repellence ability while charges of opposite types gravitate to each other and are compensate during the connection making the body neutral.
The law of charges interaction was studied experimentally in 1785 by Charles-Augustin de Coulomb with the help of elaborated sensitive torsion balance (Coulomb 2007). He found out that the interaction force between charged bodies is inversely proportional to the distance squared between them.
At present, it is impossible to imagine the life without electricity. The most convenient transportation of electricity in the network is transformer. It is used for increase of generator voltage at electric power stations before electrical energy transportation, and then for decrease of the voltage of power transmission line to the acceptable level of consumers. Transformer is the device on transformation of alternating current of one voltage into alternating current of another voltage at the unchangeable frequency without essential losses of power based on the principle of electromagnetic induction. […]