Subelement A: Principles— Topic 1: Electrical Elements
Question 3-1A1
Element 3 (GROL)The product of the readings of an AC voltmeter and AC ammeter is called:
Explanation
In an AC circuit, an AC voltmeter measures the RMS (Root Mean Square) voltage, and an AC ammeter measures the RMS current. The direct product of these two readings (Volts RMS × Amps RMS) is defined as **Apparent power**.
Apparent power is the total power that appears to be supplied by the source. It is "apparent" because it does not account for the phase difference that can exist between the voltage and current waveforms in circuits containing reactive components like inductors or capacitors. Its unit is Volt-Amperes (VA).
**True power** (or real power) is the actual power consumed by the resistive portion of the circuit and dissipated as heat or used to do work. It is measured in Watts and is calculated as Apparent power multiplied by the **Power factor** (which accounts for the phase difference). **Current power** is not a standard electrical term.
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