On Sat, 6 Mar 2004 22:31:57 -0700, you wrote:

>Just wonderin what the 3rd pin on a typical power barrel connector is
>typically used for? This is the pin that connects to the center pin when
>there's no plug and it's not connected when there's a plug.
>
>In the past I've just left it NC, but I wonder if it should be used to
>ground the + input to the power supply.  There's a 7805 and a couple of =
2200
>uF caps on this line.
>
>And yes, it is 10:30 Saturday night; and no, I don't have a life :-)
>

It's for a cut-out when the DC input replaces an internal battery.

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads