Cathode Modulation

Author: J.B. Hoag

The details of a cathode-modulation system are shown in Fig. 28 F.

Fig. 28 F. Cathode-modulation. Both of the condensers C should be less than 0.002 μfd.

It is to be noted that, when filament-type tubes are used, there is need for a separate filament transformer in the modulated stage of the r.f. amplifiers. The bypass condensers for this filament should not have a capacitance greater than 0.002 μfd. in order to avoid bypassing the a.f. When the proper operating conditions have been established, the cathode current will be nearly constant, with or without modulation.