I was looking at this StackExchange question:
I ran the simulation and I'm confused by the behavior. On the rising edge of the clock the left side of the capacitor charges to a positive voltage. Shouldn't the right side be negative, since current is flowing out of that side?
And then a side question: I set up the circuit on a breadboard and ran it, with a clamping diode, and did not get a suppression of the negative spike. In fact, I get the same behavior with or without the diode.