Hi sayzer,

I entirely agree with your comments. I guess at the end of the day it all depends on what compromises in accuracy a designer is willing to make. For testing of code a simple voltage divider is more than adequate.

I tend to stay away from using a logic supply rail for use as a reference for a transducer, or indeed the A\D reference pin, as the voltage at any given time is not accurately known and there is always a lot of noise present.

Another method could be to use a precision regulator to provide the excitation voltage for the transducer and also the A\D reference.

For 'one off' circuits it is easy to accept things the way they are, but for production runs, calibrating out various design issues can be costly.

I suppose if the transducer and refernce pin are tied to the same point they can float around together and provide the required accuracy.

The forum has served its purpose. Leonzio now has a number of ideas to work with and if more people reply even more ideas will abound. The beauty of it all is we never stop learning from each other.

Regards Mike B.

Quote - Always borrow money from a pessimist, as they never expect it back.