It is said that ,the maximum output voltage is only half that of the maximum secondary voltage since only half of it is rectified at any time due centre tapping. why?

1. For a bridge, three additional POWER components
to fail, uses four rather than one diode.

2. For center tapped plus two rectifier FW circuit,
requires CT transformer, and one additional POWER
diode to reduce realibility.

3. Any diode going short-circuited, places remaining
diodes across the circuit AC supply, leading to very
high damaging current which MUST be protected against.

4. For the CT plus two diodes circuit the diodes require
double the voltage rating of the HW or Bridge FW.