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The instrumentation amplifier is a modiffiction for the OPAMP difference amplifier whose input resistance is reletivly small.Two OPAMP's voltage followers are used at the inputs but not only buffering can be achieved but also additional gain can be achieved by connecting resistances rather than short circuting in the voltage followers feed back loops and additional resistance connecting their inverting terminals .This additional resistance controls the performance of the insrumentation amplifier.
summer amplifer:-
If we take three equal resistors and connect one end of each to a common point, then apply three input voltages (one to each of the resistors' free ends), the voltage seen at the common point will be the mathematical average of the three.
Instrumentation amplifier:-
The instrumentation amplifier is a modiffiction for the OPAMP difference amplifier whose input resistance is reletivly small
Three equal resistors and connect one end of each to a common point, then apply three input voltages (one to each of the resistors' free ends), the voltage seen at the common point will be the mathematical average of the three.
The instrumentation amplifier is a modiffiction for the OPAMP difference amplifier whose input resistance is reletivly small
a summer amplifier basically adds two signals,where as an intrumentation amplifier can be used to realize various mathematical expressions by setting different resisitor values.
a summing amplifiers output is either equal or propotional to the sum of the inputs
applied. there can be n number of inputs depending upon the current sinking
& sourcing capability of the op amp
while instrumentation amplifier is basiclly used to drive the output produced from
any sensor b/c its loading effect is almost neglegible...
Instrumenation amplifier boosts only the difference of the input signals while attenuating the common-mode signal. The attenuation is given by CMR value and is usually about 90dB. It is used for example by measuring ECG signal (weak potential difference at 2 points) while the capacitively coupled 50/60Hz common-mode can be minimized by CMR value.
we take three equal resistors and connect one end of each to a common point, then apply three input voltages (one to each of the resistors' free ends), the voltage seen at the common point will be the mathematical average of the three.
The instrumentation amplifier is a modiffiction for the OPAMP difference amplifier whose input resistance is reletivly small
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