CAMRT Radiography Practice Exam

Autotransformers operate based on which principle?

1. Direct induction

2. Mutual induction

3. Self induction

4. Electromagnetic induction

The correct answer is: Self induction

Autotransformers operate based on the principle of self-induction. This is a fundamental concept in electromagnetism, where a change in current in a coil of wire induces a voltage within the same coil. In autotransformers, a single coil serves both as the primary and secondary winding, allowing for efficient voltage transformation without the need for multiple separate windings. In this configuration, when an alternating current flows through the coil, a magnetic field is created. This magnetic field induces a voltage in different sections of the coil, allowing the transformer to step up or step down the voltage based on the number of turns of wire involved. The self-inductive nature of this process means that the autotransformer can effectively modify the voltage level while minimizing energy losses typically associated with other transformer types that rely on mutual induction between separate coils. Understanding self-induction is crucial for grasping how autotransformers function, especially in applications where variable voltage levels are desired, such as in X-ray equipment and other radiographic devices.