ESA Certified Alarm Technician Practice Exam

A transformer works by the use of _________________.

1. Static electricity

2. Induction

3. Magnetic resistance

4. Direct current

The correct answer is: Induction

A transformer operates based on the principle of induction, specifically electromagnetic induction. This process involves transferring electrical energy between two or more coils of wire through a magnetic field. When an alternating current flows through the primary coil of the transformer, it generates a varying magnetic field. This magnetic field induces a voltage in the secondary coil according to Faraday's law of electromagnetic induction. The effectiveness of a transformer is reliant on the alternating nature of the current, which is necessary for inducing voltage across the secondary winding. Static electricity does not play a role in the functioning of transformers, as it involves stationary electric charges rather than changing magnetic fields. Similarly, magnetic resistance is not a principle used in transformers; instead, transformers utilize magnetic fields created by alternating current. Finally, direct current does not work with transformers because it lacks the varying magnetic field needed to induce voltage in the secondary winding. Through this understanding of induction, it becomes clear why it is the correct answer in the context of how transformers operate.