Transformaator

A transformaator, more commonly known as a transformer, is an electrical device that transfers alternating-current energy between two or more circuits through electromagnetic induction. It typically changes the voltage and current levels while conserving power, provided the losses are small. The device usually consists of a magnetic core and at least two windings—the primary and the secondary—coupled by the core.

Principle and construction: When an alternating voltage is applied to the primary winding, a changing magnetic flux is produced in the core, which induces a voltage in the secondary winding according to Faraday's law. The voltage ratio is approximately equal to the turns ratio N2/N1. Power transferred is ideally the same in both windings (excluding losses). Real transformers exhibit core losses (hysteresis and eddy currents) and winding losses (copper losses), and are designed to minimize stray losses. Transformers are typically built with laminated steel cores to reduce eddy currents; high-frequency transformers use ferrite or powdered-iron cores. Transformers can be isolated (two separate windings) or autotransformers (single winding with taps).

Applications: In electrical power systems, power transformers step voltages up or down for transmission and distribution. Instrument transformers provide scaled voltages or currents for measurement and protection. Small transformers are used in power supplies, audio equipment, and medical devices. A transformer transfers energy rather than generating it, so the primary must supply the power. Safety and standards address insulation, ventilation, and thermal management, with installation and rating governed by electrical codes.