Input Tracking Property of an Op-Amp

Thread Starter

amjg92

Joined Dec 14, 2010
12
Hi, I need help to understand what is the Input Tracking Property of an Op-Amp, and the conditions under which it applies. I seem not to be able to find anything on the web about it. All I can understand is that it has something to do with the difference in voltage between the input terminals. Am I totally off the track?
Thanks
 

justtrying

Joined Mar 9, 2011
439
I am not sure what you are referring to...

in presence of negative feedback, input at two pins is the same as they are (for analysis purposes) seen as shorted together. This means that voltage difference between two input terminals must remain 0V. Whatever voltage is applied at one input is seen at another.

http://www.allaboutcircuits.com/vol_3/chpt_8/4.html
 
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Thread Starter

amjg92

Joined Dec 14, 2010
12
I have found out that the tracking property only exists if there is a feedback loop and the op-amp is not in saturation. As vp - Vn = Vd the difference in voltage between the terminals.
but I need a derivation of this property
 

thatoneguy

Joined Feb 19, 2009
6,359
An op amp will output whatever voltage it takes, within supply limits, to keep the voltage at the + and - terminals equal.

This applies to amplifiers, followers, inverters, etc.
 
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