The 'Rectifier Keys' are
SE = Single ended, only one
power supply voltage is generated.
BP = Bipolar (not the disorder),
it means two voltages of opposite polarities are generated.
HW = half wave, only one
FW = Full Wave, two camel
WTF = you know this one
BR = bridge rectifier
VD = not what you think,
but would you believe Voltage Doubler?