Contribution to bioelectric potential recording technique

Abstract

A symetrical output stage for amplifiers composed by two vacuum tubes coupled by a common cathodic resistor is described, The equations giving the most adequate value for the gain of the System have been established.

There is described also a balanced imput circuit insensitive to electrostatic flutuations, using a 6L7 and a 6J5 vacuum tubes, the latter as a phase-changer and the former as a mixing tube.