Which instrument is best suited for analyzing the frequency of signals?

The oscilloscope is the best instrument for analyzing the frequency of signals because it provides a visual representation of electrical signals over time. By displaying the waveforms, users can easily observe and measure various characteristics of the signal, including its frequency, amplitude, and shape. The horizontal time axis allows for precise time measurements, facilitating accurate frequency calculations based on the observed waveforms.

In contrast, a multimeter typically measures voltage, current, and resistance, but does not visualize signals over time, making it inadequate for frequency analysis. A transformer is used primarily for changing voltage levels in AC circuits and does not measure frequency. A relay is an electromechanical switch used for controlling circuits but does not analyze signal characteristics. Thus, the oscilloscope stands out as the definitive tool for frequency analysis in electronic applications.