(under subclass 129) Subject matter involving a vacuum tube amplifying device whose input electrode bias voltage and/or bias control voltage for the same amplifying device is supplied from a resistive circuit network in the cathode to ground path of the vacuum tube amplifying device whereby the plate current flowing through such resistor, which is usually by-passed for signal current frequencies, develops a D.C.. bias voltage at the cathode.
(1) Note. The subject matter in this subclass includes both adjustable self-biasing means cathode circuit self-biasing means, per se, without an adjustable feature, for vacuum tube amplifying device input electrodes. Input electrode bias means without a control feature is classified elsewhere.
SEE OR SEARCH THIS CLASS, SUBCLASS:
70+, for amplifiers having series energized amplifiers devices.
87+, for cathode impedance feedback.
203, and 204, for input electrode biasing. See (1) Note above. 254, and 278+, for semiconductor transistor amplifiers having signal amplitude (volume level) control.
290, for semiconductor amplifiers having D.C.. bias control feedback for stabilization.
296, and 297, for semiconductor amplifiers involving bias or power supply circuitry.
SEE OR SEARCH CLASS
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,
530+, for miscellaneous electron tube circuits with particular bias means.
