Power supply to provide negative voltage - considerations

Hi,

If I have to supply -3 V to a circuit, can I just flip the power terminals on the power supply and expect the power supply to source current as needed to run my circuit.
By flipping I mean, connect the ground of my circuit to the positive on the power supply and connect the negative terminal (node requiring -3V) of my circuit to the gnd of my power supply.

Now the question is, can any power supply source the necessary current to run my circuit or do I need to know any specific feature of the internal construction which will allow this kind of sourcing of current & also provide the negative voltage for my circuit to run. For example if I use a DAQ board which has a digital pin output from 0 to 5V, for this application, can it source the current & provide the negative voltage necessary for my circuit?

Very confused question. What does "if I use a DAQ board which has a digital pin output from 0 to 5V, for this application, can it source the current & provide the negative voltage necessary for my circuit?" even mean?

First of all, yes a power supply can supply negative voltage if the (+) and (-) terminals are isolated from ground. Like flipping a battery. BUT if the negative terminal is connected to ground then, of course, you CAN'T use if for a negative supply unless everything else in your circuit is isolated from ground. I think you need to sketch something up just to get yourself straightened out.

Hi,

for sure you can any floating +3V supply use a -3V supply.

Current: you just need to know the current consuption. The supply shoud be rated for more current than the application needs. Independent of positive or negative supply.

A digital output pin is not meant to supply a ciruit with power.
Althouh - as long as you keep within the specifed range - it could work.


Klaus