This video shows an example of performing a simple component test (curve tracer) on an oscilloscope. The simple circuit shown is often called an Octopus (I don't know why), and it's been around for decades, in many variants. You can Google search on Octopus component tester, oscilloscope curve tracer, etc. and find dozens and dozens of variants. In the video, I boil the circuit down to its simplest implementation, describe how it works, and demonstrate how you use it.