Question about regulating voltage

Question about regulating voltage

Does anyone know if a 12V zener diode would be appropriate in regulating a DC voltage of 12V 0.3A in this diagram? Also, what would happen if the voltage drops below 12V? Would the voltage still go through, or would it be stopped completely?

submitted by /u/ilalalayou
[visit reddit] [comments] http://ift.tt/2Ck1Ft6