Definition of loop gain and return difference in transistor feedback amplifiers

The paper reviews the position of feedback theory in relation to the design and analysis of transistor amplifiers, in this context, it is claimed that there is less connection with the formal theory of feedback than is usually supposed. In particular, the use of loop gain as a means of investigating stability does not necessarily require an interpretation in terms of signal flow round actual closed loops, and such an interpretation can even be positively misleading on occasions. It is suggested that whatever is needed from feedback theory can, and should, be introduced in terms of conventional network theory.