High-frequency generator
AssigneeU.S. Philips Corporation
InventorsChristian S. A. E. Patron, Eugene J. Sowinski, Aart P. Huben
Life of this patent
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Abstract
In a high-frequency generator (1) comprising a multigrid electron tube (2), the control grid (3) and the screen grid (4) are substantially d.c. coupled. The tube then oscillates via the internal parasitic capacitance between the screen grid (4) and anode (5) without requiring an external feedback circuit. A reduction of the heat dissipation and a compact electron tube are the result with high oscillation frequencies likewise being attainable. A high-frequency decoupling of the control grid (3), with an intermittent operation of the generator (1), results in a very limited heat dissipation, causing the generator (1) to be very compact.
Claims16
A high-frequency generator comprising:
- a multigrid electron tube comprising at least a cathode, an anode and a grid pair including a control grid and a screen grid, a power supply circuit coupled to said anode and cathode, means coupling said tube to a load, the grid pair being coupled to a main current path of the electron tube, a feedback circuit between the screen grid and the anode for generating a high-frequency signal in the main current path of the electron tube, characterized in that the feedback circuit substantially comprises an internal parasitic capacitance present between the screen grid and the anode of the electron tube, and an impedance element coupled between the control grid and the screen grid, said impedance element having an a.c. impedance with respect to the high-frequency signal that exceeds its d.c. resistance.
A high-frequency generator comprising:
- a multigrid electron tube including a cathode and an anode which define a main current path in the tube, a control grid and a screen grid coupled to said main current path,
- first means for coupling said anode and cathode to a source of supply voltage for the tube,
- a feedback circuit between the screen grid and the anode for generating a high-frequency signal in the main current path of the tube, wherein said feedback circuit substantially comprises an internal parasitic capacitance present between the screen grid and the anode of the tube, and
- second means including an impedance element for coupling the control grid to the screen grid in a manner such that said control grid and said screen grid are each at substantially the same DC voltage level relative to the cathode, said impedance element having an AC impedance for said high-frequency that exceeds its DC resistance.
Dependencies are inferred from the claim text.