Cathode heating apparatus for an electronic power tube
AssigneeThomson-CSF
InventorJean-Claude Lecornet
Life of this patent
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Abstract
An apparatus for heating the cathode of an electronic power tube, having a supply for delivering a heating current to the cathode, an interrupter circuit for periodically interrupting the flow of heating current to the cathode, and controls for controlling the duration of these periodic interruptions and for regulating the net amount of heating current. To achieve this, the controls include a voltage control that varies in such a way so as to bring the heating current from a value of O to Io (where Io is the correct heating current at which the tube will be in a pre-heated condition) during a first, predetermined time period, and then from a current Io to a current Im (where Im is the optimum value for the heating current when the tube is normally operating), during a second predetermined time period.
Claims5
An apparatus for heating a cathode of an electronic power tube having a direct heated cathode, said apparatus comprising:
- feeding means for feeding a heating current to said cathode;
- interrupter circuit means for interrupting said feeding of a current to said cathode;
- and control means coupled to said interrupter circuit means for controlling the interruptions by said interrupter circuit, with a predetermined frequency, and with a duration of passing of current which varies as a function of time which has elapsed, for bringing said heating current from O to Io, which is the effective value of said heating current for which said tube is in a pre-heating condition, and for then bringing said heating current from Io to Im which is the effective value of said heating current when said tube is in its normal operating condition, Im being greater than Io.
Dependencies are inferred from the claim text.