How do you determine the power factor of an AC circuit?

How do you determine the power factor of an AC circuit?

• A. By measuring voltage only
• B. By measuring current only
• C. By dividing real power by apparent power
• D. By multiplying resistance by voltage

Answer: (C)

To determine the power factor of an AC circuit, the appropriate method involves dividing real power by apparent power. The power factor is a measure of how effectively electrical power is being converted into useful work output and is expressed as a number between 0 and 1 or as a percentage. Real power, measured in watts, represents the actual power used by electrical devices to perform work, while apparent power, measured in volt-amperes (VA), is the product of the voltage and current in the circuit, without regard to the phase angle. The power factor provides insight into the efficiency of the power being utilized in the circuit. Thus, by calculating the ratio of real power to apparent power, you can discern the power factor, which helps identify how much of the electrical power is effectively used in doing useful work as opposed to just being apparent power that does not contribute to productive output. This critical distinction makes the correct approach clear, as simply measuring voltage or current alone does not provide sufficient information to evaluate power factor, nor does multiplying resistance by voltage, which pertains more to Ohm's law and does not reflect the conditions of an AC circuit.

To determine the power factor of an AC circuit, the appropriate method involves dividing real power by apparent power. The power factor is a measure of how effectively electrical power is being converted into useful work output and is expressed as a number between 0 and 1 or as a percentage.

Real power, measured in watts, represents the actual power used by electrical devices to perform work, while apparent power, measured in volt-amperes (VA), is the product of the voltage and current in the circuit, without regard to the phase angle. The power factor provides insight into the efficiency of the power being utilized in the circuit.

Thus, by calculating the ratio of real power to apparent power, you can discern the power factor, which helps identify how much of the electrical power is effectively used in doing useful work as opposed to just being apparent power that does not contribute to productive output.

This critical distinction makes the correct approach clear, as simply measuring voltage or current alone does not provide sufficient information to evaluate power factor, nor does multiplying resistance by voltage, which pertains more to Ohm's law and does not reflect the conditions of an AC circuit.