If alternating current is applied to the anode of a diode, what would you expect to see at the cathode?

A diode allows current to flow in only one direction—from its anode to its cathode. When alternating current (AC), which swings between positive and negative voltages, is applied to the anode, the diode only conducts during the positive half of the cycle. During the negative half of the cycle, the diode blocks the current. As a result, the output at the cathode consists of half-cycles of current flowing in a single direction, separated by gaps of zero current. This resulting waveform is called "pulsating direct current." It is not a steady direct current because it hasn't been smoothed out by a capacitor yet, and it is no longer alternating because the current never reverses direction.