Do 214AB vs do-214AC?
DO-214AB, also known as SMC, is the largest size. DO-214AC, also known as SMA, is the smallest size.
How do I choose the right size diode?
The reason for selecting a diode with certain parameters is as follows: Reverse Voltage: Select to be above the highest possible reverse voltage that might be seen across the device. (When the diode is off.) Forward Current: Select to be above the highest possible current that might be seen flowing through device.