Instrumentation amplifiers (sometimes shortened to In-Amps) are a type of precision gain block used in electronic and measurement test equipment. Instrumentation amplifiers act as a differential amplifier; a type of electronic amplifier that amplifies the voltage difference between two inputs but suppresses any voltage signals that are common to the two inputs. RS offer a range of instrumentation amplifiers from several trusted brands in the industry, including Analog Devices, Microchip, Texas Instruments, and more.
Instrumentation amplifiers are almost always composed of 3 op-amps (operational amplifiers) and several resistors. They provide the most important function of CMR (common-mode rejection) by cancelling out any signals that have the same potential as received by both of the inputs. Any signals that have different potentials get amplified. They are used for low frequency signals (such as <1MHz), which they amplify whilst also cutting out any common-mode noise that may be present in the input signal.
An instrumentation amplifier measures small signals in a noisy environment. The noise generally is "common-mode noise" (the difference between the noise-free common-mode voltage and the actual common-mode voltage). An instrumentation amplifier uses its common-mode rejection to distinguish the noise from the signal of interest. Instrumentation amplifiers are needed in nearly every field of electronics, particularly in the test and measurement industry. They can be used as a voltage follower, selective inversion circuit, a current-to-voltage converter, active rectifier, integrator, a variety of filters, and a voltage comparator.
Unlike instrumentation amplifiers (In Amp), operational amplifiers (Op-Amp) are high-gain voltage amplifying devices with a differential input.