How to visualize two signal waveforms simultaneously on the screen of an oscilloscope?

Answer 1

Two methods are commonly used. The first is 'chopped' mode where the two signals are alternately displayed. By adjusting the offsets, each signal can be clearly seen. The chopped mode works for fairly slow signals, much lower frequency than the chopping frequency. For higher speed signals the 'alternate' mode is used. In the alternate mode one signal is displayed for one horizontal sweep time then the second is displayed on the next sweep. The following sweep returns to the first signal and the process repeats.
This is basically what happens inside a dual-channel analog oscilloscope. There were external units sold quite a while ago to provide dual trace capability on a single trace oscilloscope.
There was a third method used, the true "dual beam" oscilloscope which had two actual electron beams and two sets of deflection plates. This was an expensive instrument and not very common.

Answer 2

u require minimum 2-channel oscilloscope for that. connect one signal to first channel and the other signal to second channel. keep scope on DUAL mode (both channels on.)