In the formula P = V × I × PF, what does PF stand for?

• A. Power Factor
• B. Phase Frequency
• C. Peak Flux
• D. Pulse Factor

Answer: (A)

PF stands for Power Factor. In AC circuits, voltage and current can be out of sync because of inductive or capacitive elements. Real power, the useful power that does work, is the portion of the apparent power (V × I) that actually does work, and that’s found by multiplying by the power factor: P = V × I × PF. A power factor of 1 means all the current contributes to useful work (a purely resistive load). If PF is less than 1, some current is circulating without doing useful work due to phase difference. The other terms listed aren’t part of this relationship: phase frequency, peak flux, and pulse factor don’t describe how much real work is produced from the electrical supply.