Instruumendivõimendi

Instruumendivõimendi, often referred to as an instrumentation amplifier, is a differential amplifier with very high input impedance, high common-mode rejection ratio, and low DC offset. It is designed to amplify small signals that are close to a large common-mode voltage. Unlike a basic operational amplifier configured as a differential amplifier, an instrumentation amplifier typically uses three op-amps and a few resistors.

The core of an instrumentation amplifier is its ability to amplify the difference between two input signals while rejecting any voltage that is common to both inputs. This makes it ideal for amplifying signals from sensors like thermocouples, strain gauges, and bridge circuits, which often have small differential signals superimposed on larger common-mode noise. The high input impedance ensures that the amplifier does not draw significant current from the signal source, thus preserving the integrity of the measured signal.

The gain of an instrumentation amplifier is usually set by a single external resistor. This simplifies circuit design and allows for precise gain adjustment. The high common-mode rejection ratio (CMRR) is crucial for accurate measurements in noisy environments, as it effectively filters out unwanted interference. Instrumentation amplifiers are widely used in data acquisition systems, medical equipment, and industrial control applications where precise amplification of low-level signals is required.