Which tool measures voltage, frequency, and phase in electrical signals?

• A. Oscilloscope
• B. Multimeter
• C. Spectrum Analyzer
• D. Function Generator

Answer: (A)

Measuring voltage, frequency, and phase in electrical signals is best done with an oscilloscope. It displays voltage as a function of time, so you can see the waveform’s amplitude and how long each cycle takes, which gives you the frequency. To get phase, you compare two waveforms on two channels or use a reference trigger; the horizontal shift between corresponding features (like peaks) tells you the phase difference, and you can convert that time shift into a phase angle using the relation phase = 360° × f × Δt. Modern digital scopes often provide automatic readings for frequency and phase as well. A multimeter mainly reports voltage levels and, on some models, frequency, but it doesn’t show waveform shapes or phase relationships. A spectrum analyzer shows how signal energy is distributed across frequencies, focusing on frequency content rather than the time-domain phase between signals. A function generator is a source of test signals, not a instrument for measuring them.