Instrumentation amplifier amplification derivation formula as shown:
Instrumentation amplifier , which is a special differential amplifier with ultra-high input impedance, extremely good CMRR, low input offset, low output impedance, can amplify those signals in the *** mode voltage.
The realization of the instrumentation amplifier circuit is mainly divided into two main categories: the first type of discrete components combined; the other type of monolithic integrated chip directly realized. According to the existing components, respectively, single op-amp LM741 and OP07, integrated four op-amp LM324 and monolithic integrated chip AD620 as the core, designed four instrumentation amplifier circuit scheme.
With the rapid development of electronic technology, operational amplifier circuits are also widely used. Instrumentation amplifier is a precision differential voltage amplifier, which originated from operational amplifiers, and better than operational amplifiers. Instrumentation amplifier to the key components integrated within the amplifier, its unique structure so that it has a high **** mode rejection ratio, high input impedance, low noise, low linearity error, low misalignment drift gain setup flexibility and ease of use and other characteristics, so that it is in the data acquisition, sensor signal amplification, high-speed signal conditioning, medical instruments and high-grade audio equipment and so on are favored. Instrumentation amplifier is a closed-loop gain component with differential input and single-ended output relative to the reference end, with differential input and single-ended output relative to the reference end. Unlike an operational amplifier, where the closed-loop gain is determined by an external resistor connected between the inverting input and the output, an instrumentation amplifier uses a network of internal feedback resistors isolated from the inputs. Instrumentation amplifiers apply an input signal to the 2 differential inputs and the gain can be internally preset, set internally by the user through the pins, or preset through external gain resistors isolated from the input signal.