Oscilloscope

An oscilloscope is electronic test equipment that shows voltage as a signal. The signal is usually a graph of electrical differences. The vertical axis plots the function of time and the horizontal axis shows the voltage.
An oscilloscope is used in the lab to measure sine and cosine waves and it is easy to use and you can learn how to use it quickly.

In an oscilloscope you can measure 2 waves at one time the same as the picture, you can change the voltage and the current. In addition, you can also measure the period, frequency, amplitude and peak to peak of the wave.

References:
www-ese.fnal.gov
commons.wikimedia.org