instrumentation amplifier [‚in·strə·men′tā·shən ′am·plə‚fī·ər]
Instrumentation amplifier
differs from an operational amplifier (op-amp), which ideally has infinite open-loop gain and must be used in conjunction with external elements to define the closed-loop transfer function. At one time built in discrete or hybrid form using operational amplifier and resistor networks, instrumentation amplifiers are readily available as inexpensive monolithic integrated circuits. Typical commercial amplifiers provide present gains of 1, 10, 100, and 1000. In some cases, the gain may be set to a special value by one or more external resistors. The frequency response invariably is flat, extending from 0 (dc) to an upper frequency of about 1 kHz to 1 MHz. See Integrated circuits, Operational amplifier
(electronics)
An amplifier that accepts a voltage signal as an input and produces a linearly scaled version of this signal at the output; it is a closed-loop fixed-gain amplifier, usually differential, and has high input impedance, low drift, and high common-mode rejection over a wide range of frequencies.
Instrumentation amplifier
A special-purpose linear amplifier, used for the accurate amplification of the difference between two (often small) voltages, often in the presence of much larger common-mode voltages, and having a pair of differential (usually high-impedance) input terminals, connected to sources Vin1 and Vin2; a well-defined differential-mode gain ADM; and a voltage output Vout, satisfying the relationship given in the equation below. It
Instrumentation amplifiers are used to interface low-level devices, such as strain gages, pressure transducers, and Hall-effect magnetic sensors, into a subsequent high-level process, such as analog-to-digital conversion. See Amplifier, Differential amplifier, Pressure transducer, Strain gage
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