Thanks very much for those detailed explanation on Negative feedback.

Now willing to discuss about Instrumentation Amplifier.

[Edited]



I did the above circuit up to my knowledge and willing to know how good it is.

Description of the circuit:

- U2A and U3A are used as high resistance buffer to prevent loading the signal source heavily ( By 'loading the signal source' i assume drawing high current from the input source V1 and V2)
- The circuit is designed to amplify the input voltage of range (0 to 10)mV into 500 times.
- The high resistance buffer stage gives a gain of 5 (when R5 set to 1K), when V1 not equal to V2. The difference between these two buffer outputs is amplified 100 times by the differential stage U4A.
- When V1 = V2, The high resistance buffer stage acts as a voltage follower.(But not sure of how that happens)

I would like to have some comments on this.

Is this a correct way to design an instrumentation amplifier when need to be used for a practical application?


regard's
Suresh.