floating outputs on psu

[amateur_25]

Hi
Am I correct in saying floating outputs on psu means you can swap the +ve and -ne to get a negative voltage?
If so does it matter if the pre regulator that feed the output regulator has a gnd pin?

Here's a block diagram

200va transformer ->rectifier -> l200c (has gnd pin) -> lt3080 (floating output)

[gxti]

Negative voltage is simply a matter of choosing a reference. Even if the power supply's "ground" is the negative terminal, as long as it floats you can simply designate the positive terminal as ground and use it as a negative voltage supply.