US2956205A - Cold-cathode stepping tube - Google Patents

Description

Oct. 11, 1960 Filed July 18, 1958 G. O. CROWTHER COLD-CATHODE STEPPING TUBE 4 Sheets-Sheet 1 INVENTOR. GEMLD OFFLEY Czeownzm AGEN T Oct. 11, 1960 G. o. CROWTHER 2,956,205

' COLD-CATHODE STEPPING TUBE Filed July 18, 195a 4 Sheets-Sheet 2 INVENTOR GERALD OFFLEY CROWTHER BY MA- AGENT Oct. 11, 1960 G. o. CROWTHER 2,956,205

COLD-CATHODE STEPPING TUBE Filed July 18, 1958 4 Sheets-Sheet 3 INVENTOR GERALD 0F F LE Y GROWTH! R AGENT Oct. 11, 1960 s. o. CROWTHER 2,956,205

COLD-CATHODE STEPPING TUBE Filed July 18, 1958 4 Sheets-Sheet 4 FIG;8

lNV ENTOR GERALD OFFLE Y CROWTHER BY M E.

AGENT United States Patent COLD-CATHODE STEPPING TUBE Gerald Oflley Crowther, Cheam, England, assignor to North American Philips Company, Inc., New York, N.Y.

Filed July 18, 1958, Ser. No. 749,461

Claims priority, application Great Britain July 26, 1957 4 Claims. (Cl. SIS-84.6)

This invention relates to neon discharge counting tubes having a central anode and a plurality of rod-shaped main cathodes symmetrically surrounding the anode, with between every two main cathodes two likewise rod-shaped auxiliary electrodes, which bring about transfer of the discharge from one main cathode to a succeeding main cathode, the auxiliary electrodes being connected in parallel as two rows.

In US. patent application Serial No. 723,404, filed March 24, 1958, now US. Patent No. 2,905,860, issued September 22, 1959, it has already been suggested to displace one of the main cathodes, viz. the zero or marking cathode, with respect to the other electrodes, so that the voltage difference between the anode and the marking cathode which is necessary for transfer of the discharge to this cathode is higher than for the other cathodes. Consequently, upon transfer of the discharge to the marking cathode, it is possible to derive from the tube a higher voltage pulse sufiicient for direct control of a tube connected in cascade to the first tube.

It has been found that if, on the one hand, the condition must be fulfilled that the biassing potential to be applied to the marking cathode in the circuit is not very critical and, on the other hand, that the transfer from the marking cathode via the auxiliary electrodes to the succeeding main cathode should take place with security, the structure according to the prior application is not always satisfactory.

An object of the invention is to provide a construction which is not very critical in regard of the biassing potential of the marking cathode and in which the discharge from the marking cathode may be displaced Without difiiculty.

According to the invention, in a neon discharge counting tube having a centrally-arranged anode and a plurality of nod-shaped main cathodes symmetrically surrounding the anode, with between every two main cathodes two likewise rod-shaped auxiliary electrodes, which bring about transfer of the discharge from one main cathode to a succeeding main cathode, which auxiliary electrodes are connected in parallel as two rows, part of the zero or marking cathode is displaced with respect to the other electrodes so that the voltage difference between the anode and said part of the marking cathode which is required for transfer of, the discharge to said part is higher than for the other cathodes, while the ratio of the distances between said part of the marking cathode and the preceding first and second auxiliary electrodes is substantially the same as for the other cathodes, the marking cathode having a second part which is also displaced outwards, but which is at the same distance from the succeeding first auxiliary electrode as are the other main cathodes.

It has been found that the above-mentioned ratio must satisfy the specified conditions, because otherwise the on the arcuated dot-and-dash line r.

biassing potential of the marking cathode becomes too critical for the circuits normally applied, while the second part of the marking cathode must be sufficiently close to the succeeding first auxiliary electrode to permit a certain transfer to this auxiliary electrode.

The invention will now he described with reference to the accompanying drawing, in which:

Figs. la, 1b and 1c are, respectively, a plan view, a sectional view taken along the line II-II, and a diagrammatic view of an electrode structure for a tube according to the invention;

Fig. 2 is a diagrammatic view of an electrode structure according to the invention.

Figs. 3, 4 and 5 are plan views of a plurality of electrode arrangements according to the invention, of which Figs. 6, 7 and 8 are the side-views.

Fig. 1 shows a portion of the electrode arrangement of a decade counting tube. S is a ceramic disc in which the cathodes and auxiliary electrodes are fixed. The anode (not shown) is a disc parallel to the plane of drawing having a diameter a little less than corresponding to the positioning of the electrodes in the disc S. Of the electrodes there are shown the main cathode K9, the associated first auxiliary electrode GA9 and the second auxiliary electrode GB9. The cathode K0 is positioned outside the curved line on which the other electrodes are situated. Normally, the electrode K0 would have to occupy the position indicated by X. The position of electrode K0 is chosen so that the ratio of the distances d1 and 112 to the first and second preceding auxiliary electrodes is substantially the same as f the electrode would have occupied the position indicated by x.

In order to bring about with security a transfer from K0 to GAO, the electrode K0 would have to be situated Fig. 2 shows the position of electrode K0 if this condition were fulfilled for the electrode K0 displaced outwards.

However, if will be evident that, in the case of Fig 2, the ratio between d1 and d2 approaches unity much more than in the case of Fig. 1. This results in the biassing potential to be applied to K0 being critical.

Figs. 3 and 6 show how the electrode K0 is composed of two parallel rods 1 and 2 which are united by welding at 8 by means of the bent portion 7 of Fig. 6.

In Figs. 4 and 7, the electrode K0 comprises an L-like rod having limbs 3 and 4 such that the discharge passes via GA9 and GB9 to the point of 3 and can pass from the bend between 3 and 4 to GAO.

In Figs. 5 and 8, the electrode K0 comprises a rod 6 having a plate 5 welded thereto.

What is claimed is:

1. A glow discharge tube comprising an anode, a plurality of rod-shaped main cathodes symmetrically disposed about and surrounding the anode, a plurality of rod-shaped auxiliary electrodes spaced from and between adjacent main cathodes to effect a transfer of the discharge from one cathode to an adjoining cathode, said auxiliary electrodes being connected in two parallel rows, and a rod shaped marker cathode having a first portion for the transfer of the discharge thereto positioned relative to the auxiliary electrodes at which the potential difference between the anode and the portion of the marker cathode required for transferring the discharge thereto is higher than for the other cathodes, the ratio of the distances between said portion of the marking cathode and the next preceding auxiliary electrodes being substantially the same as for the other cathodes, said marker cathode having a second portion similarly positioned and being at substan Patented Oct. 11, 1960 tially the same distance from the next succeeding auxiliary 4. A glow discharge tube as claimed in claim 1 in which electrode as are the other main cathodes. the marker cathode comprises a rod having a platelike 2. A glow discharge tube as claimed in claim 1 in which Portion Secured theretothe marker cathode com rises two arallel s aced rods joined together by a bent iaortion of ne of the rods. 5 References Clted 1n the file of thls Patent 3. A glow discharge tube as claimed in claim 1 in which UNITED STATES PATENTS the marker cathode is L-shaped. 2,739,266 Burnett Mar. 20, 1956

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