Red Seal Industrial Electrician Exam 2025 – 400 Free Practice Questions to Pass the Exam

The frequency of an AC signal can be accurately measured using a frequency meter or an oscilloscope because these instruments are specifically designed to analyze the characteristics of electrical waveforms. A frequency meter measures the number of cycles per second (Hertz) directly, making it a straightforward tool for this purpose. An oscilloscope, on the other hand, visually represents the waveform of the AC signal, allowing the user to determine the frequency by measuring the time period of one complete cycle and applying the relationship between frequency and period (frequency = 1/period).

Other methods of measurement listed do not provide a direct or accurate measurement of frequency. Calculating total resistance is related to DC circuits and does not pertain to the frequency of AC signals. A multimeter set to measure AC voltage can provide voltage readings but typically does not measure frequency. Visual observation of waveforms can give a qualitative sense of frequency but lacks the precision needed for accurate measurement. Thus, using a frequency meter or oscilloscope is the correct and most effective approach to determining the frequency of an AC signal.