Regeneration in Coupled Circuits

1-The simple theory of regeneration in a single oscillatory circuit is developed, both when the oscillatory element is in the plate circuit and in the grid circuit of the regenerating tube. 2-The theory of couple circuits having positive resistances is reviewed and illustrated by means of space models for the secondary current. The use of sections of the model for determining graphically and for visualizing the variations of secondary current as the primary or secondary circuits are changed or as the impressed wave length is varied, is given. The positions of the two peaks of max. max. secondary current, when the coupling is greater than critical, is shown to depend upon the relative values of R/(Lω
0
) = η for the two circuits. When the ratio of η
1
/η
2
is unity, the two peaks are symmetrically located on the space model with respect to the primary and secondary axes, otherwise the space model is unsymmetrical. 3-The theory of regeneration in coupled circuits is developed. It is shown that regeneration in the secondary circuit affects only the impedance of that circuit and may make the equivalent resistance of that circuit zero or negative. The first case taken up assumes the regeneration to be constant, so that the theory for this case is the theory for coupled circuits, one of which has a negative resistance. The boundary equation between oscillation and non-oscillation is derived and plotted.