A basic transformer is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction. It consists of two essential components: the core and the windings.
Core: The core is typically made of a magnetic material such as iron or steel. Its primary function is to provide a closed magnetic path for the magnetic flux generated by the alternating current (AC) passing through the windings. The core's design and material properties affect the transformer's efficiency, performance, and size. Cores can be categorized into two main types:
Iron Core: These transformers have a solid core made of laminated iron sheets. These sheets are stacked together and insulated to minimize eddy current losses and improve overall efficiency.
Air Core: In certain applications where high-frequency operation is required, an air core transformer might be used. In such transformers, there is no solid magnetic material; instead, the windings are suspended in air. Air core transformers have lower coupling efficiency compared to iron core transformers but are suitable for applications where size and weight are critical, such as in radio frequency circuits.
Windings: The windings are conductive wires wound around the core. There are two types of windings in a basic transformer:
Primary Winding: This is the input winding where the alternating current is applied. It generates a changing magnetic flux within the core due to the alternating current passing through it. The magnetic flux induces a voltage in the secondary winding.
Secondary Winding: This is the output winding where the induced voltage from the primary winding's magnetic flux is collected. The voltage induced in the secondary winding is proportional to the turns ratio between the primary and secondary windings.
The number of turns in each winding directly affects the voltage ratio between the primary and secondary sides of the transformer. If the primary winding has more turns than the secondary winding, it's called a "step-up" transformer, as it increases the voltage from the input to the output. Conversely, if the secondary winding has more turns, it's a "step-down" transformer, decreasing the voltage from the input to the output.
In summary, the core provides a path for the magnetic flux, while the windings create the magnetic fields that induce voltages across the windings. Transformers are essential components in power distribution systems, allowing voltage levels to be adjusted for various applications while minimizing power losses during transmission.