On Thu, 3 Jan 2008 09:55:38 -0800 (PST), you wrote:

>I've used the 2 wire RTDs  before...essentially measure the voltage across the device for the temperature, but I've been asked to look at 3 wire or full bridge RTD's.  Now, they talked like they are one and the same but I think a full bridge is a 4 wire?  4 wire seems simple enough in that it has a constant current source to get better accuracy but what about 3 wire devices?  A current source that dumps into a common ground?  Just need some clarification on that.

With 3 wires you can sense the resistance of one RTD wire and make the
assumption the other wire will be the same. 

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