medical electronics III

Luckily, we don't have to build all of this because commercial instrumentation amplifiers are available. The AD620 has a CMRR of 100 dB with a differential gain that is adjustable up to 1,000. This is done by changing the value of a resistor, RG on the input of the chip. . By buying a commercial amplifier we also don't need to worry about the offset null because the internbal circuits is perfectly balanced in the factory.