Instrumentation amplifier

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Image:Opampinstrumentation.png

An instrumentation amplifier is a type of operational amplifier that has been specifically designed to have characteristics suitable for use in measurement and test equipment. These characteristics include very low DC offset, low drift, low noise, very high open-loop gain, very high common-mode rejection ratio, and very high input impedances. They are used where great accuracy and stability of the circuit both short- and long-term are required.

The gain is calculated as follows:

<math>{V_\mathrm{out} \over V_\mathrm{in}} = -\left (1 + {2 R_1 \over R_\mathrm{gain}} \right ) {R_3 \over R_2}</math>

There are also integrated devices available such as the AD620 (approx 12$) or AD624 (approx 35$) from Analog Devices

See also

External links

it:Amplificatore da strumentazione