The same scientific instrument requires its name and purpose.

Oscilloscope is a widely used electronic measuring instrument. It can transform electrical signals invisible to the naked eye into visible images, which is convenient for people to study the changing process of various electrical phenomena. Oscilloscope uses a narrow electron beam composed of high-speed electrons to hit the screen coated with fluorescent substances, which can produce tiny light spots. Under the action of the measured signal, the electron beam, like a pen tip, can draw the curve of the instantaneous value of the measured signal on the screen. Oscilloscope can be used to observe the waveform curves of different signal amplitudes changing with time, and can also be used to test various electric quantities, such as voltage, current, frequency, phase difference and amplitude modulation.