Red Seal Construction Electrician Practice Exam

What is the primary function of a transformer?

1. To measure electrical current

2. To increase (step-up) or decrease (step-down) voltage levels between circuits

3. To convert AC to DC current

4. To isolate electrical circuits from ground

The correct answer is: To increase (step-up) or decrease (step-down) voltage levels between circuits

The primary function of a transformer is to increase (step-up) or decrease (step-down) voltage levels between circuits. This process is crucial for the efficient transmission of electrical power over long distances. In power distribution, high voltages are often used to minimize energy loss during transmission. When the electric power reaches the consumption point, transformers are utilized to step down the voltage to a safer level that can be used by homes and industries. Transformers operate on the principle of electromagnetic induction, where a varying current in the primary winding creates a varying magnetic field, which induces a voltage in the secondary winding. By adjusting the number of turns in the coils (windings) of the transformer, this technology allows for precise control of voltage levels required for different applications. The other options address functions that do not pertain to the fundamental role of a transformer: measuring current, converting AC to DC, or isolating circuits. While these are important aspects of electrical systems, they represent different components or devices in electrical engineering rather than the core function of a transformer.