Diode Circuits

Full wave gives twice the average output of half wave and a ripple at twice the line frequency, so it needs less filtering.

A clipper removes part of the waveform; a clamper shifts the whole waveform by charging a series capacitor to a DC level. A clamper preserves the peak-to-peak swing.

Pick the crudest model the question allows: ideal for a first pass, constant-drop for most numericals, and the exponential only when the question gives $\eta V_T$. The load line finds the operating point when the model is not linear.

The capacitor holds the output up between peaks, so the ripple is whatever the load drains in one cycle. Note the full-wave case discharges for half as long, which is where the factor of 2 comes from.

The series resistor carries both the load current and whatever the Zener takes. Design questions are always the two extremes: minimum input with maximum load must still keep the Zener in breakdown, and maximum input with no load must not exceed its power rating.