Red Seal Industrial Electrician Practice Exam

Which component improves power factor in electrical circuits?

1. Transformer

2. Resistor

3. Capacitor

4. Inductor

The correct answer is: Capacitor

The component that improves power factor in electrical circuits is the capacitor. In electrical systems, the power factor is a measure of how effectively electrical power is being converted into useful work output. A power factor less than 1 indicates that some of the power is reactive power, which does not perform any real work but instead oscillates between the source and the load. Capacitors are used in circuits to counteract the effects of inductive loads such as motors and transformers, which tend to draw a lagging current and thus lower the power factor. By placing capacitors in parallel with inductive loads, they introduce a leading current that can offset the lagging current due to the inductive components. This balancing act helps reduce the phase difference between voltage and current, thereby improving the power factor towards unity (1) and increasing the efficiency of the electrical system. Other components mentioned do not serve this purpose in the same way. Transformers are primarily used for voltage conversion. Resistors dissipate energy as heat without improving power factor. Inductors, similar to transformers, also create reactive power and do not assist in power factor correction; in fact, they can exacerbate poor power factor conditions.