US2019770A - Vacuum tube arrangement and circuit - Google Patents

Description

NW. 5 E35. i v 1 p, PRINZ I ZMEQJW VACUUM TUBE ARRANGEMENT AND CIRCUIT Filed July 2 1, 1933 r 3 4) I I mm mammal mm 1 T 1E.+ \mmuwwm mm 2i INVENTOR K3;- J DIETRI VPRINZ B jf/ v a,

ATTORNEY Patented Nov. 5, 1935 ATENT OFFICE VAG'UUM TUBE ARRANGEMENT AND CIRCUIT Germany Application July 21, 1933, Serial No. 681,516 lln Germany July 15, 1932 Claims.

A purpose of the present invention is to provide a novel tube and circuit arrangement wherein a series of plates is disposed within a vacuum tube amplifier in such a manner that with 5 variation of the grid voltage the respective plate circuits will be successively energized.

A further object of the invention is to arrange the elements of a tube and the relative voltages applied thereto, that a virtual cathode is formed outside of the grid and means are provided to change the position of this cathode in the tube.

Other and further objects of the invention will become apparent to those skilled in the art as the description thereof proceeds. For a better understanding of the invention reference is made to the accompanying drawing in which, several embodiments of the invention are shown. In said drawing, 1

Fig. l is a schematic circuit arrangement also showing the relative arrangement of the tube elements;

Fig. 2 is a schematic arrangement showing a modified form of the invention; and,

Fig. 3 is a schematic arrangement also showing a partial section of the tube elements of a modification of the tube of Fig. l.

The invention is concerned with an arrangement free from inertia, which, in the presence of continuous variation of a voltage, allows of making sequentially a plurality of circuits without the use of movable relays or similar means.

The invention is predicated for its operation upon the use of electron tubes which are furnished with a hot cathode and a surrounding grid being at a positive potential in reference to the said cathode. In a tube of this sort, the electrons issuing from the cathode fly across to and through the grid, and if no other electrodes with a high positive potential are present,

they gradually lose their velocity, come to rest and finally return to the grid. The plane or surface wherein the electrons are caused to reverse may be called a virtual cathode, inasmuch as it acts like a source of electrons. The position of this virtual cathode depends upon the size or volume of emission of the actual cathode and the potential of the grid so that the virtual cathode recedes so much more from the grid, the lower the emission and/or the higher the grid potential.

Now, according to the invention, inside the tube, a plurality of plates are disposed at different distances from the grid, the potential of the said plates being slightly positive in relation to 55 the cathode, in other words, of such low positive value that the formation of the virtual cathode (so-called) will not be appreciably disturbed thereby. With each of these plates is connected a circuit. If, then, the grid voltage is progresslvely raised from zero to a more positive value, 5 the virtual cathode will recede from the grid and thus will successively reach the various plates, with the consequence that the connected circuits will sequentially be traversed by current.

Referring now to Fig. l, i denotes the heated 10 cathode of a vacuum tube T, 2 a cylindrical grid formed in the usual manner, and 3, 4 and 5 a series of plates arranged at different distances from grid 2 and in spaced apart planes with respect to the axial center of the grid. As shown 15 in Fig. 1 the plates are plane or substantially plane surfaces having two oppositely disposed connected sections. Numeral t is the grid voltage battery and is adjustable whereby a range of positive voltages may be applied to the grid. 20 Such a battery may consist of a number of series connected cells and the grid voltage will then depend on the number of cells connected in the grid circuit and may thus be easily varied. The common plate battery is denoted by l and 26 this is ordinarily chosen of lower value than battery 6 so that only a low potential is impressed on the plates such as not to prevent the formation of a mass or aggregation of electrons constituting a virtual cathode. Numerals 3, 9 and 30 it denote the impedance or useful loads in the plate circuits.

Starting the battery 6 at zero value, substantially no plate current will ilow and as the voltage of t is increased to a value where a mass 01' electrons collects between plate 3 and grid 2, plate current will flow through plate circuit 3 and energize load 8. In this condition plates 4 and 5 are so remote from the virtual cathode that substantially no current ilows to them. 40

As the battery 6 and thus the voltage of grid 2 is increased, the mass of electrons will collect closer to plate #3 and when within its influence they will travel to it, thus creating plate current 5 in plate circuit 4 and load 9. In a similar manner, as the voltage of ii is further increased, the position of the virtual cathode will approach 5 and current will flow therethrough and through load It. By lowering the voltage of battery 6 and grid 2, it will be obvious that current flow through loads It, 9 and 8 may be stopped.

The arrangement shown in Fig. 3 is generally the same as that shown in Fig. 1 and operates in the same manner. As here shown the plates are in the form of cylinders of increasing diameter and surround the grid and cathode.

By uniting the anodes 3, 4 and 5 with one another, as shown in Fig. 2, then the arrangement may be used for the purpose of obtaining a terrace-type output current characteristic curve. In this case the plates may be fiat surfaces as shown in Fig. 1 or may be in the cylindrical form as shown in Fig. 3. The separate consuming or load devices 8, 9 and Ill of Fig. 1 are here shown combined into a unitary load impedance H in which flows a current which, as a function of the grid voltage supplied by source 6, results in a terraced characteristic. By suitably shaping the anode, of course, other forms or shapes of characteristic may be obtained.

Having described my invention, what I claim 1s:

1. In a device of the class described, the combination of an electron discharge tube having a cathode and at least two plates arranged at different distances from said cathode, a single control grid extending substantially the entire length of said cathode and located between said plates and cathode, plate circuits connecting said plates and cathode and including a common source of potential, and a source of potential having its negative terminal connected to said cathode and its positive terminal to said grid whereby a virtual cathode may be formed closely adjacent either of said plates in accordance with the potential of said source.

2. In a device of the class described, the combination of a vacuum tube having a cathode and two plates arranged at difierent distances therefrom, a control grid located between said cathode and plates, means for impressing a positive voltage of given value on said grid, a plate circuit connecting said cathode and plates and including control grid and at least two plates arranged at 5 different radial distances from said grid, a source of voltage connected between said grid and cathode arranged to impress a positive voltage on said grid of such a value that a virtual cathode is formed between said grid and the inner plate and 10 means for increasing the voltage on said grid whereby the virtual cathode moves outwardly toward the other of said plates.

4. In a device for energizing successive circuits, the combination of a vacuum tube having a cathl5 ode, a control grid, and two plates arranged at different distances from said grid, a plate circuit having two branches connected between said cathode and plates each of said branches including an impedance and means for applying a posi- 20 tive voltage of variable value to said control grid whereby said branch circuits are successively energized.

5. In a device of the class described, the combination of a vacuum tube having a cathode, at 25 least two plates located in different planes and at different radial distances from said cathode,

a plate circuit including a source of voltage and an individual impedance connected to .each of said plates, a control grid positioned between said 30 cathode and plates and means for impressing a potential of adjustable amount which is positive with reference to said cathode on said control grid whereby said impedances may be successively energized and a virtual cathode formed at a distance from said cathode which is greater or less than the distance between the inner plate and cathode.

DIETRICH PRINZ.

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