in my electronics lab at university we were studying diodes and I stumbled upon a behaviour that I cannot understand nor explain (I'm I physics undergrad, not and EE).
The circuit we were analysing is a simple single diode rectifier (a 1N4148 signal diode) with a 100 ohm load in parallel with a 330uF electrolytic cap and a 50Hz input sine wave. I noticed that the input signal was clipped. To eliminate the doubt that the problem was to be caused by something other than the circuit (signal generator, oscilloscope etc) I simulated it in LTSpice and got the same result, whitch is the one in the image.
Why is the circuit doing this? If I measure directly the input signal shouldn't I see a 50Hz sine wave?