What is the principle of the transformer?

The action of the transformer is based on the phenomenon of electromagnetic induction. The simplest transformer consists of a steel magnetic circuit and two windings located on it. The windings are made of insulated wire and are not electrically connected. One of the windings is supplied with electrical energy from an alternating current source. This winding is called primary. Consumers are connected to another winding, called secondary, (directly or through a rectifier). When a transformer is connected to an alternating current source (electrical network), an alternating current l1 flows in the turns of its primary winding, forming an alternating magnetic flux F. If any receiver is connected to the secondary winding, then under the action of E2, the EMF current I2, induced in each turn of the primary and secondary windings of the transformer, flows through its circuit, according to the law of electromagnetic induction, depends on the magnetic flux penetrating the turn and the rate of its change. The magnetic flux of each transformer is a certain value, depending on the voltage and frequency of the alternating current in the source to which the transformer is connected. The rate of change of the magnetic flux is also constant, it is determined by the frequency of change of the alternating current. Consequently, the same EMF is induced in each turn of the primary and secondary windings. As a result, the ratio of the effective values ​​of the EMF E1 and E2 induced in the primary and secondary windings of the transformer will be equal to the ratio of the numbers of turns N1 and N2 of these windings.