The output of a half/full wave diode when the diode(s) is connected to an AC transformer and there is no capacitor is called AC or DC? It does not change to negative plot, so I am in doubt what to call it?
Besides I saw an animation of how to generate DC by just sutable using of comotators, the out was like the output of a full wave rectifier without a cap and they called it an DC generator?!
If you use a single diode, you rectify only half the waves (either all the positive halves or all the negative halves) hence the term half-wave rectifier. If you use four diodes in bridge configuration ( or two diodes with a center-tap transformer), then it rectifies both halves of the waveform and it's called a full-wave rectifier.
In general the rectified, unfiltered signal from a diode rectifier can be considered pulsing DC or DC with high ripple (it's typical of many battery chargers which have no filter), although it still does have a significant AC component and harmonics (as a spectrum analyzer will measure).
This rectification technique is used in RF circuits (particularly microwave)as a frequency doubler (since a full-wave rectified signal has a fundamental frequency twice the input frequency).