US1585464A - Electron-discharge apparatus - Google Patents

Description

May 18 192 6.

S. L. CLOTHIER ELECTRON DISCHARGE APPARATUS Filed May 29, 1924 Inventor Stewart, .C|othier-;

His Attorney l atented May 1926.

' UNITEDI STATES PATEN STEWART L. CLOTHIER, OF :SOHENECTADY, NEW YORK; FRANK 'S. .CLOTHIER, GUARD- i,5s5,464 OFFICE.

' IAN OF SAID STEWART L. CLOTHIER; ASSIGNOR'TO GENERAL ELECTRIC COMPANY,

A CORPORATION OF NEW YORK.

ELECTRON-DISCHARGE APPARATUS. i I.

. 5 trodes.

One of the objects of my invention is to provide an improved circuit organization for use with adevice of the type mentioned whereby the amplification which may be obtained with such a device may be increased.

In connection with electron discharge devices of the thermionic type having a grid for controlling the flow of current between cathode and anode it has been proposed to employ a second grid between the cathode and control grid, and to impress upon this second grida constant positive potential somewhat lower than that of-the anode.

grid used -in this way is commonly known as a space charge grid; 'The purpose of this grid is to lower the impedance between the cathode and anode, and for this purpose the grid has ordinarily been maintained at a constant positive potential. .It

- has been observed, however, that the curv rent flowing from .this spacecharge grid varies in the opposite way from the man ner in whichthe current to the anode varies when acted upon by the control grid. That is, as the current to the 'anodeincreases the f and vice versa.

, the space 0 current to the space charge grid decreases, If an impedance is placed in'circuit with arge grid the vcurrent variations 3a m the circuit of the space charge grid will 40 charge 4 cause the potential of the space charge-grid to vary.

, 'A'more specific object of myinvention is to produc dpotential variations of the space i which will act upon the controlfgri through the ca acity existing between the two grids, and commonly'known' .as a regenerative efi'ect,

thereb increasing the amount of amplifica-f 46 tionw ich can be produced by means. of the tube.

It has "'be en prop osed iniVan der Bijl .Patent 1,479,779 to provide an inductive feed-back coupling- 'betweenthe circuit of 5Q the space charge grid and the circuit of the control grid and produce regeneration in this way. In this case the direction of the coupling between the two circuits must be produce. what is Application filed May 29, 1924. Serial 170. 716,821.

arranged in the opposite manner to that of three-electrode device, -by reason of the capacitycoupling between 'the' plate and grid, when the plate. circuit is *properly tuned, the usual adjustment of the plate circuit employed in this case is not suitable for the adjustment of the circuit of the space.

charge grid in the fo ur;electrode device because of'the fact, as pointed out above, that the current in the two circuits vary in opposite directions. I have discovered that thedesired feed-back through'the capacity between the twoxgrids may be obtained ifv the impedance of the space charge "grid'has a suitable capacity rea'ctance. The novel features which I believe to be characteristic of myinvention are set forth with particularity in the appended claims,

my invention itself, however, both as to its organization and method of operation will best be understoodby reference to the fol-' lowing description taken in connection with the accompanying drawing 1 and 2 show diagrammatically-two difi'erent circuit arrangements which may be employed for carrying my inve'ntion into efect. i I have indicated in the drawing the application of my invention to the reception and detection of radio signals. I have shown in the drawing an electron discharge device 1 having themsual electron emitting, cathode in which Figs.

2, anode 3, control grid 4, and space charge grid 5. Signals from the antenna 6 are impressed upon the circuit of the control gr d in the usual manner. The space charge grid 5 is connected by a suitable tap 7 to the battery 8, which supplies the necessary plate potential for the operation of the device. I

In Fig. 1 I have shown in the circuit of the space charge grid a variable inductance 9 and variable capacity 10 in parallel. By suitable adjustment of these impedances the desired regenerative effect may be obtained. I have found that the adjustment of the circuit is not especially critical as when it has once been adjustedto a sensitive. point it is still sensitive over a considerable range of wave lengths. It does not require readjustment every time that the tuning of the input circuit is changed.

The arrangement of Fig. 2 diifers from that of Fig. 1 only in that the entire adjustment of the circuit of the space charge grid is accomplished by means of a variomcter 11. I. have found-that the natural capacity of the variomcter, which I have in dicated by a shunt condenser 12, is in some cases sufi'icient to produce the proper adjustment of the phase relation of the potential of the space charge grid with respect to that of the control grid to produce the desired regeneration.

\Vhile I have shown and described only two modifications of my invention, it is evident that the phase of the potential of the space charge grid with respect to that of the control grid may be adjusted in various other ways to secure the desired result and that my invention maybe cmploycd with any type of circuit connection in which regenerative amplification is desired.

- What I claim as new and desire to secure by Letters Patent of the United States, is

1. An amplifying apparatus comprising an electron discharge device having an electron emitting cathode, an anode and two grids interposed between cathode and anode.

circuit connections between the cathode and each of the other electrodes, means for supplying electrical variations to be amplified to the circuit between the cathode and the grid nearest the anode, means for producing resultant variations of the potential of the grid nearest the cathode, and means for ad' justing the phase of the resultant variations in the potential of the grid nearest the cathode to produce an increased amplification.

2. An amplifying apparatus comprising an electron discharge device having an electron emitting cathode, an anode and two grids interposed between cathode and anode, circuit connections between the cathode and each of the other electrodes, means for supplying electrical variations to be amplified to the circuit between the cathode and the grid nearest the anode, means for producing resultant variations of thepotential of the grid nearest the cathode, and means for adjusting the phase of the resultant variations in the potential ofthe grid nearest the cathode to produce an increased amplification by reason of the capacity relations between the two grids. I 3. An amplifying apparatus comprising an electron discharge device having an elec tronemitting cathode, an anode, and two grids interposed between cathode and anode, circuit connections between the cathode and each of the other electrodes, means for supplying electrical variations to be amplified to the circuit'between the cathode and the grid nearest the anode, and means for producing a regenerative effect by reason of the capacity relations between the two grids, and thereby increasing the amplification.

4. An amplifying apparatus comprising an electron discharge device having an electron emitting cathode, an anode and two grids'interposed between cathode and anode, circuit connections between the cathode and each of the other electrodes, means for supplying electrical variations to be amplified to the circuit between the cathode and the grid nearest the anode, and nicans for iinpressing upon the grid nearest the anode through the capacity between the two grids electrical variations substantially in phase with those originally supplied thereto.

In witness whereof, I have hereunto set my hand this 28th day of May 1924.

" STEWART L. CLOTHIER.

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