How do power transformers work?

How do power transformers work?
Power transformers operate based on Faraday’s law. Simply put, they use electromagnetic induction to connect two circuits, transferring current from one circuit to the other. As mentioned earlier, the voltage may sometimes increase or decrease during the transfer process depending on changes in energy demand. However, the frequency of the current remains constant.

Power transformers consist of a magnetic core, a primary winding, and a secondary winding. In a transformer diagram, the structure looks like a square (the core), with two wires (the primary and secondary windings) wound around each vertical side. These windings carry isolated currents and are connected to each other through the central magnetic core. In a transformer, current is introduced through the primary winding, which generates an electromagnetic field in the core, which in turn generates a voltage in the secondary winding. The voltage or current in the secondary winding is the current that is sent out, completing the power transfer from the primary circuit to the secondary circuit.

What does a step-up transformer do?
A step-up transformer is a type of power transformer that takes a low voltage and increases it when transferring it to another circuit. While the voltage increases from the primary circuit to the secondary circuit, the current decreases. However, the frequency remains constant during transmission.

A step-up transformer still contains a primary winding, a secondary winding, and a magnetic core. It operates based on the principle of electromagnetic induction.

Using an electromagnetic field, voltage and current are transmitted through the wires of the secondary winding. However, in a step-up transformer, the primary winding has a higher voltage and fewer turns around the core than the secondary winding. The secondary winding has more turns to increase the voltage in the secondary wire and transmit it to a new circuit with higher voltage and lower current.

Step-down transformer
What does a step-down transformer do?
Step-down transformers operate in the opposite manner to step-up transformers. They receive a high voltage from one circuit and convert it to a lower voltage before transmitting it to another circuit. Step-down transformers differ in that they increase the current while reducing the voltage. However, like step-up transformers, the frequency remains constant in step-down transformers.

The internal structure of a step-down transformer is similar to that of a step-up transformer. It consists of a primary winding, a secondary winding, and a metal core. It receives current in the primary winding and transmits the converted current through the secondary winding using the electromagnetic field generated by the core. However, unlike the step-up transformer, the main winding has more turns. This inversion of the structure helps the step-down transformer reduce the voltage when transferring current from one circuit to another. The step-down transformer is also known as an autotransformer.