Instrumentation amplifiers (In Amp) use multiple op amps to create an input stage and an output stage. The block diagram displayed here shows a typical three op amp instrumentation amplifier using voltage feedback amplifiers. Due to this topology, the system has very high input impedance, open loop gain, and common mode rejection ratio. These characteristics, in addition to high precision and low noise, are particularly important when dealing with sensitive sensors and small signals riding on a common mode signal.