Ohio Assessment for Educators (OAE) Integrated Science (024) Practice Exam

Which device is used to increase or decrease the voltage of alternating current?

1. Condenser

2. Transformer

3. Resistor

4. Rectifier

The correct answer is: Transformer

The device that is used to increase or decrease the voltage of alternating current is a transformer. A transformer operates on the principle of electromagnetic induction and consists of two or more coils of wire (or windings) that are linked by a magnetic field. When alternating current flows through one coil, it creates a changing magnetic field that induces a voltage in the other coil. The voltage can be increased or decreased by adjusting the ratio of the number of turns of wire in the primary coil (input) to that in the secondary coil (output). If the secondary coil has more turns than the primary, the voltage increases (step-up transformer); if it has fewer turns, the voltage decreases (step-down transformer). This ability to modify voltage makes transformers essential in electrical power systems, allowing for efficient transmission of electricity over long distances and ensuring compatibility with different devices and circuits.