In the previous video we did a detailed circuit analysis of the famous Discrete BJT Curve Tracer circuit you can find all over the web.
Now that we know how it works, we can think how to improve. I here present to you two versions, the first one alone improves by a lot the characteristic of the transistor under test visible on the oscilloscope.
However... a weird effect is still visible on the screen.
To remove it, it was first necessary to understand where it came from, and turns out that parasitic capacitance plays a significant role in it. The first option is to build a good circuit, meaning avoiding in the first place creating capacitive couplings between the terminals of the transistor. If that isn't sufficient.. The second version I present you exploits a little trick to remove that effect from the oscilloscope screen.