In this picture from Volume III of the All About Circuits textbook, there is a voltage clamper and a half-wave voltage doubler. I have two questions. The first is, if you just have the clamper (b), will the clamper itself double the voltage during the half of the AC cycle that it is not charging? The second is, in the doubler (a), you have two capacitors that charge to 5V in series, plus the original 5V from the AC source. Why doesn't that give you 15V? Is it because one or the other of the capacitors is always charging?

 

First Q: Don't understand your question.
The output of circuit (b) is a sinewave equal to the input with the negative peak clamped at -0.7V.

Second Q: Yes.
If you want 15V then you need a tripler circuit, not a doubler circuit.