Abstract: A multibeam-inductive-output-tube amplifier comprises an output cavity and a plurality of electron guns each intended to emit an electron beam through the output cavity, each electron gun comprising a cathode intended to emit the electron beam and a gate allowing the density of the electron beam to be modulated. The amplifier comprises, associated with each gun, a DC voltage supply, each of the supplies connected to the gate of the corresponding electron gun so as to bias the gate. The voltage of at least one of the supplies is adjustable so as to balance the density of the various electron beams.

Abstract: A multibeam-inductive-output-tube amplifier comprises an output cavity and a plurality of electron guns each intended to emit an electron beam through the output cavity, each electron gun comprising a cathode intended to emit the electron beam and a gate allowing the density of the electron beam to be modulated. The amplifier comprises, associated with each gun, a DC voltage supply, each of the supplies connected to the gate of the corresponding electron gun so as to bias the gate. The voltage of at least one of the supplies is adjustable so as to balance the density of the various electron beams.

Abstract: An amplifier including an electronic tube with an axial electron beam, provided with a cathode and at least two collectors, and at least two sources of DC voltage. Each collector is connected to a DC voltage source having a potential difference such that, the further the collector is from the cathode, the lower the potential difference between this collector and the cathode. The DC voltage sources are connected together at a common point situated at the collector whose potential difference with the cathode is the lower but not zero.

Abstract: An amplifier including an electronic tube with an axial electron beam, provided with a cathode and at least two collectors, and at least two sources of DC voltage. Each collector is connected to a DC voltage source having a potential difference such that, the further the collector is from the cathode, the lower the potential difference between this collector and the cathode. The DC voltage sources are connected together at a common point situated at the collector whose potential difference with the cathode is the lower but not zero.

Abstract: A high frequency heating generator which includes an electron tube amplifier, the output of which is connected to a resonant circuit that is electromagnetically coupled to a part to be heated, and a controlled frequency oscillator. The oscillator outputs a high frequency signal to the input of the amplifier. It also includes circuitry to measure the phase shift between the current output to the resonant circuit and the voltage at its terminals, and to modify the frequency of the oscillator as a function of this phase shift. The invention can be applied notably to devices for heating by electromagnetic induction, dielectric losses or plasma.