Abstract: An amplifier capable of operation in four modes singly or in combinations is disclosed. The modes are: DC amplification mode, AC amplification mode, suppressed baseline mode, and offset correction mode. In the DC amplification mode, the amplifier operates as a conventional DC amplifier. In the suppressed baseline mode, the outputs of the input and output amplifiers are connected back to their input stages through a long time constant integrator resulting in the suppression of any DC output voltage. In the AC amplification mode an RC decoupling network is inserted in the inputs to the input amplifier means to pass AC signals and reject DC components. In the offset correction mode, the inputs of the input and isolator amplifier means are shorted to create zero differential at the summing junctions thereof. Any offset voltage present at the output of the input amplifier means or output amplifier means is suppressed by means of integrated feedback to the input stage of the input and output amplifier means.