Re: [EE]: MOSFET as a digital switch by Ned Konz .

On Thursday 13 February 2003 09:09 am, you wrote: > All this talk of FET's is bringing back some fuzzy memories of it > when in class. Thats what happens when you just do digital design > for years. > > These are bidirectional devices right? Such that it doesnt matter > if the load is attached to the drain or source? Or does it matter? Yes, because there is a "body diode" between D and S. On a N-channel device, the body diode will conduct (even if the transistor is OFF) when the S becomes more than a little positive than the D. P channel devices are reversed from that. So when there's a real bidirectional current flow requirement, people tend to use two FETs with their diodes back to back. -- Ned Konz http://bike-nomad.com GPG key ID: BEEA7EFE -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.