Electronic – What happened to the second half cycle of the half wave rectifier

acdiodesoscilloscoperectifiersemiconductors

Circuit of rectifier

When I'm doing a simple half-wave rectifier with the set-up as shown above (Note: Diode D2 is not connected) and connected terminal 5 and 4 with positive and negative terminal of oscilloscope, this is what I get:

Generated trace: Terminal 5 and 4

Instead of getting a horizontal line in the second half cycle as the diode blocks the current flow in the opposite direction, I get a slanted line with a positive gradient. Can someone give me an explanation on why this happen in my experiment? I have only some basic knowledge about electronics and I'm unable to come up with a plausible explanation.

This is what I get when I connected oscilloscope to terminal 1 and 2, in case it helps:

Generated trace: Terminal 1 and 2


Edit: I uploaded the wrong picture for the my third one. I have uploaded the new picture.

Best Answer

I think you may have your oscilloscope set to block DC i.e. it is AC coupled to terminals 4 and 5. Try setting your scope input to DC.

As for your 2nd picture, you must be measuring somewhere different to where you believe you are measuring - double check your scope probe connections. Maybe what is visible is a fuzziness on the o-scope trace and this is at odds with your original trace that was clear. Maybe the ground point of your o-scope is disconnected or maybe it isn't a good photograph?