Abstract R.F. generator circuits and components therefor including an output circuit for matching the output of the power tube to a transmission line which enables the tube to be operated at power levels below that at which the output circuit is tuned while preventing destructively high plate currents from being established under such conditions by the proper selection of capacitive and inductive components to provide current-limiting resistance in the plate circuit during detuned operation; a large air capacitor in the output circuit of the power tube having metal plates which physically shape the discharge caused by instantaneously high voltages to which the output circuit may be subjected whereby corona emissions are prevented from creating large flames which can be extremely damaging to the equipment; and a power tube grid circuit which matches, in a most unique way, a driving oscillator circuit to the grid and which provides a neutralizing circuit to eliminate the adverse effects of distributive capacitants wherein the neutralizing portion of the circuit eliminates the dangerous condition of having the plate voltage separated from the grid by only a neutralizing capacitor.
Inventors
👤 Harvey James Beaudry
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-29 11:25
CPC Classifications
H; H05; H05B; H05B6/00; H05B6/02; H05B6/04
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
258 words
In an R. F. generator having a single operating frequency and a stated output power rating and which transfers power to a widely varying load through a transmission line having a characteristic impedance; a power tube having plate, grid and cathode, and having an operating capability greater than the rated power output of the generator; a circuit including inductance elements and capacitance elements, electrically disposed between said plate and the transmission line, and said inductance and capacitance elements including a pi-network formed by two capacitance elements and an inductance element therebetween; said pi-network being tuned to resonance at the operating frequency and rated power output of the generator and being detuned at all other output power levels; said inductance elements and capacitance elements having sufficiently lossy resistance characteristics under detuned operating conditions to be the predominant current limiting factor in the circuit and having a value under such detuned conditions limiting the magnitude of plate current to a level below the maximum plate current for which the tube is rated, whereby the tube will be protected from damage during operation under detuned conditions; one of the capacitance elements which forms said pi-network being formed by a plurality of lossy, parallel connected capacitors, whereby the desired degree of resistance may be more readily achieved for a given overall value of capacitance; and said resistance characteristics beinG small compared to the reactance characteristic of said inductance and capacitance elements, whereby maximum generator efficiency will not be greatly impared under tuned conditions while simultaneously limiting plate current flow under detuned operation.
Claim 2
Dependent Claim
258 words
In an R. F. generator having a single operating frequency and a stated output power rating and which transfers power to a widely varying load through a transmission line having a characteristic impedance; a power tube having plate, grid and cathode, and having an operating capability greater than the rated power output of the generator; a circuit including inductance elements and capacitance elements, electrically disposed between said plate and the transmission line, and said inductance and capacitance elements including a pi-network formed by two capacitance elements and an inductance element therebetween; said pi-network being tuned to resonance at the operating frequency and rated power output of the generator and being detuned at all other output power levels; said inductance elements and capacitance elements having sufficiently lossy resistance characteristics under detuned operating conditions to be the predominant current limiting factor in the circuit and having a value under such detuned conditions limiting the magnitude of plate current to a level below the maximum plate current for which the tube is rated, whereby the tube will be protected from damage during operation under detuned conditions; one of the capacitance elements which forms said pi-network being formed by a plurality of lossy, parallel connected capacitors, whereby the desired degree of resistance may be more readily achieved for a given overall value of capacitance; and said resistance characteristics beinG small compared to the reactance characteristic of said inductance and capacitance elements, whereby maximum generator efficiency will not be greatly impared under tuned conditions while simultaneously limiting plate current flow under detuned operation.
Claim 3
Dependent Claim
54 words
The circuit of claim 1 wherein one of the capacitance elements is electrically disposed between the plate of the tube and the remaining portions of the output circuit and operates as a blocking capacitor and is formed by a plurality of individual capacitors having relatively low-resistance characteristics at the operating frequency of the generator.