The half-wave voltage tripler
of figure 1C. requires C1 to withstand a voltage of Vm, and
both C2 and C3 to withstand voltages of 2 Vm. A good rule of
thumb is to select capacitors whose voltage rating is
approximately twice that of the actual peak applied voltage.
For example, a capacitor which will see a peak voltage of
2 Vm should have a voltage rating of approximately 4 Vm