Re: [CAD_CAM_EDM_DRO] Repeatability of Home switches

In a message dated 4/2/2003 7:46:42 PM Central Standard Time,
mgamber@... writes:

>
> The output on the switch is confusing, does sink mean that it is
> coupling the supply voltage to the output? Or is it contact closure
> like a normal switch

mgamber: "Sink" means the part has a solid-state output that "connects" the
output to GROUND or (-). "Source" means it connects the output to +, usually
+5 VDC.

Generally, "sink" is done with an NPN junction (transistor) which has its
emitter connected to (-) ground, and the collector is tied to "output".
"Source" is done various ways, but think of that as basically the "same, only
reverse-polarity" for "sketching purposes".

These two words, "sink" and "source" are used to express what semiconductor
junctions handling the output of an IC (etc.) are doing, but you might think
of a SPDT relay, the "wiper" being "output", and the other two contacts tied
to +ve and -ve. Then, as the relay is operated, it either "sources" or
"sinks". This is not the kind of explanation that makes silicon wizards
gleeful, but it is OK for beginners!

Jan Rowland, Ignernt ol' Troll



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