> Would it be better to use a high side switch?

Yes.

> If so how? I know that you
> use P type FETS, but have never done it.

Yes, a P channel FET is probably a good solution.  You need to do the rest
of the homework on exactly how to use one.

If you do this, you need to consider the voltage drop accross the FET when
on.  Unless your currents are high, this shouldn't be much of an issue
however.  If the parts you want to selectively turn off have their own
regulator, then you can put the FET at the input of the regulator.  The FET
won't effect the on voltage at all then, as long as the unregulated supply
has the additional headroom to account for the voltage drop accross the FET.
Again, this won't likely be an issue in your application, but you should do
the math to be sure.


********************************************************************
Olin Lathrop, embedded systems consultant in Littleton Massachusetts
(978) 742-9014, olin@embedinc.com, http://www.embedinc.com

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