What is the transformer?

Transformer is a device that uses the principle of electromagnetic induction to change the AC voltage. The main components are the primary coil, the secondary coil and the iron core (magnetic core). The main functions are: voltage transformation, current transformation, impedance transformation, isolation, voltage stabilization (magnetic saturation transformer) and other transformer pictures. According to the purpose, it can be divided into: distribution transformers, fully sealed transformers, combined transformers, dry-type transformers, oil-immersed transformers, single-phase transformers, electric furnace transformers, rectifier transformers, etc.

Usually we use a variety of voltages, such as life lighting is 220V, industrial safety lighting is 36V, and the voltage of the welding machine needs to be adjusted. These are inseparable from the transformer. The transformer can reduce the voltage through the principle of electromagnetic mutual inductance between the main and auxiliary coils. To the voltage we need. In the process of long-distance voltage transmission, we need to increase the voltage to a very high level to reduce the voltage loss, usually to several thousand volts or even tens of kilovolts. This is the role of the transformer. Impedance matching: The most common is in electronic circuits. In order to connect the output and input, a transformer is usually used for impedance matching, such as the old-fashioned broadcast, because the output and the input are connected, and the speakers are high-impedance speakers. , So it can only be matched with an output transformer. Therefore, transformers are inseparable from daily life, and transformers are also inseparable from industrial production.

Primary coil-induction coil or the coil through which the induced current in the transformer passes, also called the primary winding. When an AC voltage U1 is applied to the primary side of the transformer, and the current flowing through the primary winding is I1, the current will be generated in the iron core Alternating magnetic flux makes the primary and secondary windings electromagnetically contact. According to the principle of electromagnetic induction, the alternating magnetic flux will induce electromotive force when passing through these two windings. Its magnitude is related to the number of turns of the winding and the maximum value of the main magnetic flux. The voltage on the side with more winding turns is higher, and the voltage on the side with fewer winding turns is lower. When the secondary side of the transformer is open, that is, when the transformer is no-load, the voltage at the primary and secondary terminals is proportional to the number of turns of the primary and secondary windings. , The transformer serves the purpose of transforming the voltage.

Secondary coil-two coils (or loops) close to each other, when the current in one coil (loop) changes, the magnetic flux in the adjacent coil (loop) changes, and induces electromotive force or induction Current.

Iron core (magnetic core)-The function of the iron core is to strengthen the magnetic coupling between the two coils. In order to reduce the eddy current and hysteresis loss in the iron, the iron core is laminated with painted silicon steel sheets; there is no electrical connection between the two coils, and the coil is wound by insulated copper wire (or aluminum wire).