1. What is the function of a transformer?

Transformer is an electrical equipment that uses electromagnetic induction to convert an alternating voltage and current into another or several different voltages and currents of the same frequency, and is used for power transmission, distribution, and consumption in the power system. Simply put, the voltage we use for daily electricity is 220 volts, while the voltage output from common utility poles is actually 10 kilovolts. The transformer comes into play at this point, as it can convert high voltage electricity into 220 volts of low voltage electricity that we can use in our daily lives.

Because transformers can convert electrical energy into a form of high voltage and low current during transmission, and then convert it back when in use, greatly reducing the loss of electrical energy during transmission and enabling it to be economically transported to farther places. In this way, power plants can be built far away from cities. So far, most of the electricity in the world needs to go through a series of transformers to reach users. From this perspective, the function of transformers is still significant. Once a transformer malfunctions, it will cause power outages on a large scale, and the consequences will be unimaginable.

2. How does a transformer change the voltage level?

In 1831, Faraday discovered the phenomenon of electromagnetic induction through experiments, laying the foundation for the invention of transformers. Later, people invented transformers based on Faraday’s law of electromagnetic induction and Lenz’s law. Transformers generally have two independent windings wound around the same closed iron core. The input of electrical energy is called a primary winding, and the output of electrical energy is called a secondary winding. The magnetic field lines generated by the alternating current passing through the primary winding induce voltage in the secondary winding through the iron core. The difference in the number of primary and secondary windings enables voltage to achieve high and low voltage variations.