Elevator Mechanic Practice Exam

What is the standard measure of a digital multimeter readout of 440vac indicative of?

1. Peak Voltage

2. Peak-to-Peak Voltage

3. RMS Voltage

4. Steady State Voltage

The correct answer is: Peak Voltage

A digital multimeter reading of 440 VAC is indicative of RMS (Root Mean Square) Voltage. In alternating current (AC) circuits, the RMS value is the effective value of the voltage, which can produce the same amount of work (or heat) as an equivalent DC voltage. RMS voltage is a critical parameter in electrical engineering and is commonly used to measure the power delivery capability of AC circuits. When digital multimeters are set to measure AC voltage, they typically provide the RMS value, which is more relevant for understanding the energy that can be consumed by devices connected to the power source. Peak voltage and peak-to-peak voltage are typically higher than the RMS voltage and pertain to the maximum voltage levels without regard to their practical utility in circuit operations. Steady state voltage might imply a stable DC value, but in the context of AC voltage measurement, the RMS value is the standard measure that reflects its capacity to do work, which is why a reading of 440 VAC would represent RMS voltage rather than other forms of voltage measurement.