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Error n connecting resistor | Cypress Semiconductor

Error n connecting resistor

Summary: 2 Replies, Latest post by danaaknight on 25 Jun 2012 11:25 AM PDT
Verified Answers: 0
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user_201261815's picture
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43 posts

I am facing the problem in connecting the resistor  to the circuit ...i send the pic of the circuit and the error too...plz provide some information in how avoid that error.....

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user_1377889's picture
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10803 posts

Since your resistors are external parts (as all annotation components are) you have to connect them via pins to the outer world.

 

Bob

user_14586677's picture
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7648 posts

Are you trying to build a simple OpAmp summer ? If you don't need

the hi Z afforded by the PGAs you can always eliminate them. And

take your gain individulally for each channel by picking specific input

resistors. Also offset the OpAmp so circuit works with - values.

 

http://www.ecircuitcenter.com/circuits/opsum/opsum.htm

 

Right now your circuit has a gain of - 1 in the OpAmp summer, referenced to ground,

hence will not work, eg. output of OpAmp cannot swing below ground w/o you offsetting

the NI input from something higher than Vss.

 

Note dropping PGAs has the additional advantage of less offset and drift. If

you still need super high Z inputs, have to use PGA, you still have to offset the

OpAmp.

 

Regards, Dana.

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