geo:
?Make before break is a good idea, but not necessary.?
You can have a resistor always in the circuit which sets the highest voltage setting and when the switch is rotated other resistors are place in parallel, lowering the resistance and the shunt voltage.
So if the switch fails there is still a resistor setting the voltage.
I 've done this in circuits because I didn't have a make before break rotary switch, and I ended up using a center off toggle switch.
P
