US1959010A

US1959010A - Screen grid tube circuit

Info

Publication number: US1959010A
Application number: US464467A
Authority: US
Inventors: Tellegen Bernardus Do Hubertus
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1929-08-09
Filing date: 1930-06-28
Publication date: 1934-05-15
Anticipated expiration: 1951-05-15

Description

May 15, 1934. a. D. H. TELLEGEN 1,959,010

' SCREEN GRID TUBE CIRCUIT Filed June 28, 1930 l l l l l l INVENTOR BERNARDUS D. H. TELLEGEN ATTORNEY Patented May 15, 1934 PATENT OFFICE SCREEN GRID TUBE CIRCUIT Bernardus Dominicus Hubertus Tellegen, Eindhoven, Netherlands, assignor to Radio Corporation of America, a corporation of Delaware Application June 28, 1930, Serial No. 464,467 In the Netherlands August 9, 1929 Claims.

The present invention relates to improvements in, or relating to, circuit arrangements for screen grid tubes.

In the usual circuit arrangements for screen grid tubes the screen grid element is connected through a resistance to a point having a positive potential with respect to the cathode. The current passing through the screen grid being subject to variations, the voltage in the screen grid, in the said circuit arrangement, may be subject to fluctuations by reason of the potential drop in the resistance. This is an undesired phenomenon which affects the quality of reception.

According to this invention, in order to obvlate the said disadvantage of screen grid is not connected through an ordinary resistance, but rather through a neon glow lamp, or other discharge tube of similar characteristic, to a suitably chosen point of the circuit arrangement,

preferably a point of positive potential. Thus, independently of the current intensity in the screen circuit, the voltage of the screen grid is constant, as, practically, the voltage across the terminals of a neon glow lamp is independent of the current intensity in the lamp.

The novel features which I believe to be characteristic of my invention are set forth in particularity in the appended claims, the .invention itself, however, as to both its organization and method of operation will best be understood by reference to the following description taken in connection with the drawing in which I have indicated diagrammatically one circuit organization whereby my invention may be carried into effect.

In order that the invention may be clearly understood and readily carried into effect one embodiment of the invention will be described more fully with reference to the accompanying drawing, in which such an embodiment is illustrated by way of example.

Referring to the single figure, l designates a screen grid tube having its input circuit connected to a source of high frequency energy to be amplified, and having a cathode 2, a control grid 3, a screen grid 4 and an anode 5. The cathode 2 is connected to the anode 5 through a source of current 6 and the primary 6' of a transformer 7, the latter being connected to a subsequent stage. A neon lamp 8 is connected between the screen grid 4 and a predetermined point 9 of the source of current 6, or of a resistance 9 shunted across the terminals of the source of current.

Thus, the voltage between the point 9 and the screen grid 4 remains constant independently of the current intensity in the lamp 8. Obviously, circuit arrangements distinct from that shown in the drawing are also possible. Thus, for example, the neon lamp may be connected between the screen grid and the cathode, the voltage between the cathode and the screen grid being in this case determined by the operating voltage of the glow lamp. Various means known per se may be used for ensuring the ignition. The invention practically permits of any potential fluctuation of the screen grid being eliminated.

While I have indicated and described one arrangement for carrying my invention into effect, it will be apparent to one skilled in the art that my invention is by no means limited to the particular organization shown and described, but that many modifications may be made in the arrangement, without departing from the scope of my invention as set forth in the appended claims.

What I claim is:

1. A method of operating an electron discharge tube provided with a screen element disposed between the control electrode and anode of the tube, which consists in establishing a gaseous path between the screen element and a point of positive potential having a predetermined value whereby potential fluctuations in the screen element circuit are eliminated.

2. In combination with a screen grid tube circuit a source of high frequency energy to be amplified connected to the input of said circuit, a source of anode potential in the output circuit of the tube, and a gas discharge path between the screen element and said source of potential.

3. In combination an electron discharge tube provided with a cathode, control electrode, anode, and a screen element, a source of high frequency energy connected to the control electrode and cathode, a source of potential in the anode circuit of the tube, an impedance connected across said anode source, and a gas discharge tube connected between the screen element and a predetermined point of said impedance.

4. A relay circuit comprising a thermionic tube having input electrodes, output electrodes, and an auxiliary electrode, a source of signal current connected with said input electrodes, a translating circuit connected with said output electrodes, said translating circuit including a source of potential, and means for applying a constant potential to said auxiliary electrode comprising a discharge tube connecting said auxiliary electrode to a point on said source.

cuit, and means for maintaining the relaying characteristics of said tube constant comprising a discharge device connecting said auxiliary electrode to a point on said resistance.

BERNARDUS DOMINICUS HUBERTUS TELLEGEN.