Abstract: A high-frequency electron tube power oscillator includes a multi-grid electron tube (1) in which the output power is adjusted by means of an adjustable impedance element (5) connected in series with the cathode line of the tetrode (1). In order to reduce the dissipated power in the adjustable impedance element (5), the voltage across the impedance element is connected to the screen grid of the tetrode (1) through an amplifier (6) constituted by a triode (9) and a current source (10).

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.

Abstract: A high-frequency generator 1 includes a multigrid electron tube (2). A current source circuit (10) is connected to the control grid (3) or the screen grid (4) of the electron tube (2) and is arranged as an optionally adjustable current source which is also coupled to the main current path of the electron tube. This circuit defines the grid dissipation and also extends the useful life of the electron tube. If the current source circuit (10) is connected to the screen grid (4), the electron tube is further safeguarded in a simple manner against an inadmissibly high screen grid current accompanying an occasional anode voltage drop.