What is the main function of a transformer in electrical systems?

• A. To measure current
• B. To convert AC to DC
• C. To increase or decrease voltage
• D. To store electrical energy

Answer: (C)

The primary function of a transformer in electrical systems is to increase or decrease voltage levels in alternating current (AC) circuits. Transformers work on the principle of electromagnetic induction, which allows them to transfer electrical energy between two or more circuits through inductively coupled conductors.

When an AC voltage is applied to one coil of wire (the primary winding), it generates a magnetic field that induces a voltage in another coil (the secondary winding). The voltage transformation ratio is determined by the number of turns of wire in each coil. If the secondary winding has more turns than the primary, the voltage increases (step-up transformer), while if it has fewer turns, the voltage decreases (step-down transformer). This ability to adjust voltage levels is crucial for efficient power transmission and distribution in electrical systems, allowing electricity to be transported over long distances with minimal losses.

The alternative functions presented, such as measuring current, converting AC to DC, and storing electrical energy, are performed by different devices specifically designed for those purposes, and do not describe the functionality of a transformer.