1.4 Amplification

A sensor output signal with extremely low strength cannot be directly fed to the ADC input channel. These sensors need gain and buffer stages at the output and before interfacing to the ADC channel. Op amps are required to realize gain and buffer stages. The single-ended sensor output often uses a non-inverting and unity gain follower stage, but the differential sensor output needs a difference amplifier. The major benefit of the difference amplifier is its ability to reject any common mode noise while amplifying the difference voltage. Sensors such as thermocouple, pressure sensors, ambient light sensors, Current Transformer (CT) and strain gauge sensors require amplification.