Differential amplifier with regulator achieves high stability, low drift

Abstract

When d-c signals are to be amplified, the usual approach is to use a direct-coupled circuit. The difficulty of maintaining sufficiently low drift in a direct-coupled configuration led to the development of chopper and chopper-stabilized circuits, where a mechanical chopper reduces drift to low values. Unfortunately, other shortcomings arise, and in most applications the direct-coupled d-c amplifier would be preferable if the drift could be reduced to an acceptable value. The advantages over the chopper or the chopper-stabilized types include rapid recovery from overload, freedom from hash, simplicity and small size due to absence of transformers and capacitors.