US1129942A

US1129942A - Gaseous repeater in circuits of low impedance.

Info

Publication number: US1129942A
Application number: US84156814A
Authority: US
Inventors: Harold De Forest Arnold
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1914-05-28
Filing date: 1914-05-28
Publication date: 1915-03-02
Anticipated expiration: 1932-03-02

Description

, H. DE P. ARNOLD. GASEOUS RE'PBATEE IN CIRCUITS OFtLOW IMPEDANCE.

APPLICATION FILED MAY 28, 1914.

Patented Mar- 2, 1 915.

2 SHEETSSIIEET 1.

//7 Men fa /*1 v HdlO/d 0. Arno/d l V/fnes ses:

H. DE P. ARNOLD.

APPLICATION FILED MAY 28, 1914.

GASEOUS REPEATER IN CIRCUITS OP LCW IMPEDANCE.

Patented Mar. 2, 1915.

2 SHBETSSHEET 2.

//7 yen/0r. "rm/d D. Arno/d il/1 v HAROLDIDE FOREST ARNOLD, OF EAST ORANGE, NEW JERSEY. ASSIGNOR TO WESTERN ELECTRIC COMPANY, OF NEW YORK, N..Y., A CORPORATION OF ILLINOIS.

GASEOUS REPEATER IN CIRCUITS 0]? LOW IMPEDANCE.

Specification of Letters Patent.

Patented Mar. 2, 11915.

- Application filed May 28, 191a. Serial No. 841,568.

peaters generally, and of vacuum discharge repeaters more particularly, as ampl fiers without transformers;

Still more particularly, it relates to the use of thermionic repeaters for securlng amplification of current in circuits of low 1mpedance. By a thermionic current is meant current discharge from a hot cathode. Ex-

\ amples of thermionic repeaters are the De Forest audion disclosed in Patent No. 870,532,'date'd February 18, and others, the Von Leiben & Riesz r peaterd1sclosed in Patent No. 1,038,910, dated September 17, 1912, etc. By vacuum discharge is meant current discharge between elec* trodes in space from which nearly all atmosphere is exhausted. The expression vacuum discharge repeaters is intended to 1nclude-repeaters of the thermionic types-and also those in which current flows between electrodes in space maintained in a conductive state by the arc or otherwise. The mercury arc repeaterof an earlier application of this applicant, Serial No. 709,445,

filed July 13, 1912, is an example of the class of vacuum discharge repeaters but 1t is not of the thermionic type.

and especially in submarine and wireless telegraph circuits. It is particularly desirable to exclude transformers from circuits in which an exact reproduction of Wave form is necessary for legibility, as, for example, in submarine cable circuits. It is also desirable toexclude transformers from circuits in which undistorted amplification must be secured over a wide range of frequencies, as, for example, in the reproduction of speech and music. "Heretoforeit has been necessary to employ transformers in circuit with the audion in order to secure eflicient amplification of current by the audion, and this is especially true where the amplification is desired in circuits of-low impedance. This is due to the fact that the impedance of the input circuit of an efiiciently operating audion is very high, at least 100,000 ohms and in general as high as 10 megohms. Hence. in a rent amplification by the audion is lost. For example, if the impedance of the input circuit of the audion is only 100,000 ohms and 1000 ohms impedance, at least 90% of the possible currentiamplification is'lost. Moreover, in the case of audions ofthe prior art,

the impedance in the output circuit of the audion is always so great that a considerable additional loss 7 of possible amplification must occur if the output circuit of the audion is directly connected to a circuit of low impedance.

It has been discovered thataudions of the usual type may be so constructed that, with-' out the use of transformers, they will step up the input voltage of either direct current 85 7' or alternating current of any frequency in one step to asmuch as 30 times its original .value orin two successive steps to as much as 500 times its original value. The voltage amplification thus secured is entirely free from wave distortion whatever may-be the initial frequency and wave form. This typeof audion will, for convenience, be.

hereinafter referred to as the high-voltage output audion. r

It has furthermore been discovered that" audions may be constructedkwhich will step down the input, voltage, for example, to one- 65 circuit of low impedancerif no transformer is used, the larger' part of the possible curpreferably audions.

third of its original value.- This last mentioned type of audion has a high current and a low voltage output; 3 eca use of its low output impedance, suchtype of audion can be worked efliciently into a line of like impedaiicc. This new type of audion will,

' herewith.

It has been discovered that a combination of one or more of the aforementioned highvoltage output type of audions working into one of the high-current output type, will operate,.without transformers, from a line of low impedance, for example, 250 ohms, into 'a like line with a resultant current much greater, fifty or more times greater, than would flow in the second circuit if it were directly connected to'the first'circuit. The present invention-is directed to such combination of two difierent types of repeaters, A system designed to secure the same result and employing a large number of the high-voltage output type of audions connected in multiple and working into a common output circuit in lieu of a single .audion of the high-current output type, forms the subject-matter of still another application for patent in my name, Ser. No. 841,569 filed ofeven date herewith. The ,present invention may be more readily understood by reference to the accompanying drawings in which Figure 1 is a view in perspective of an audion of the high-voltage output type; Fig. 2 is a similar fragmentary View of an audion of the high-current output type; Fig. 3' is a similar fragmentary view of the two different types of audions embodied in a unitary structure; Fig.4 shows a circuit arrangement embodying this invention in which aplurality of audions of thehighvoltage. type in tandem work into'an audion of the low-voltage type; Fig. 5' shows a simplified circuit arrangement giving the same-result as in Fig. 4:; Fig. 6 shows a still further modification more particularly applicable to telephone circuits} Fig. 7 .shows a plurality of audions of the high-voltage type in tandem working into a plurality of audions of the high current output type, each of the latter feeding'into a separate output line; and Fig. 8 shows a circuit arrangement embodying theinvention in which the two different types of audions are combined in one bulb.

Like reference characters refer to like parts throughout the several views,

In the drawings, the audions 1 are of the high-voltage output type and the audions 2 are of the high-current output type. In the former type, the input electrode may be in the form of a grid. preferably made of very fine wire with a line mesh or the like, and the output anode or plate 4: is placed at a considerable distance from the cathode which is preferably a filament 5, as shown. The filament need not present a large active area. The filament, grid and plate are as usual sealed in an evacuated bulb 6. In order to secure best results in this type of audion, the grid should be near the filament, the plate should be distant from the filament, and the grid should present a finely meshed or discontinuous surface between the filament and the plate.

In the hi gh-current output type of audion, the input electrode or grid 7 may be at any side of the filament and should have a coarse mesh or preferably consist merely of a short length of wire. The output electrode or plate 8 is placed as near to the filament 9 as is conveniently possible. The filament preferably presents a large, active area. The filament, grid and plate are as usual sealed in an evacuated bulb 10. In order to secure the ,best results in this type of audion, the grid and plate should both be near the filament, the filament area should be large, and'the grid should present the least possible obstruction between the filament and plate.

As hereinbefore stated, the high-voltage output type of audion gives an amplification with low current and high voltage in its output circuit; whereas the high-current output type gives amplification with high current and low voltage, and hence low impedance, in its output circuit.

In Fig. 4, two high-voltage output audions 1, 1 connected in tandem are shown working into a high-current output audion 2. The batteries 11 are preferably of such value as to make each of the

grids

3, 3 and 7 normally about five volts negative with respect to its adjacent filament. The several filaments are heated by the respective bat teries 12. The output circuit of each audion includes its plate, a high resistance 14, a battery 13 and the filament of the audion. The resistance 14 should be, for example, 100,000 ohms or more. Theinput circuit of the first audion of the group is directly connected to the input line 15. The input voltage ,onthe grid of the first audion 1 causes an increase in the voltage of the current flowing in the output circuit of said audion,

thereby developing a voltage change on the grid of the next audion of the series, and so on. As aresult of such construction and arrangementof these audions, the voltage in the input circuit of the secondof the two I masses audions in tandem is much greater than that impressed upon the first, although the current in the interconnecting circuit is small. The audion 2 acts as an amplifier in which the current is increased and the voltage lowered in its output circuit. Because of the fact that the impedance in the output circuit of the audion 2 is lowered, it can be worked efiiciently into a line 16 of low impedance. It has been found, for example, that the amplifying means shown in- Fig. 4 will work from an incoming line of 250 ohms impedance into an outgoing line of like impedance with a resultant current of more than fifty times that which would flow in the outgoing'line if the latter were di rectly connected to the incoming line.

Fig. 5 shows a simplification of the system illustrated in Fig. 4, in that a common battery 12 furnishes current to all the filaments, said filaments being connected in series with the battery, and a common battery 13 serves for all of the plates.-

' Fig. 6 shows a further simplification of thesystem illustrated in Fig. 5. An impedance coil 17' is included in bridge of the output circuit of each audion, and in the output circuit of the two audions 1, 1,

condensers

18, 18 are inserted in series with the resistances 14. By such arrangement the several batteries 11 may be largely reduced .in voltage. This arrangement is particularly applicable to embodiment in a telephone system.

Fig. 7' shows a plurality of the high-voltage output audions in tandem working into a plurality of the high-current output audions, each of the latter working into its own output circuit 19, 20 or 21. Otherwise, the

circuit arrangement is substantially that shown in Fig. 5. The arrangement shown in Fig. 7 is particularly applicable to the operation of several loud speaking receivers from a common talking circuit.

Fig. 8 shows a structure and circuit arrangement in which an audion of the highvoltage output type works into an audion of the high-current output type, the two audions being contained in a single bulb and operating from a common filament having one branch 5 for the audion 1 and another branch 9 for the audion 2. .The input electrode 7 of the audion 2 is shown in the form of a short length of wire. The circuit arrangement is substantially that illustrated in Figs. 4 and 5, and further description thereof is deemed unnecessary. This structure and airangementhave been found tooperate successfully, without the inter osition oftransformers, between lines o the impedance of ordinary telephone lines.

As applied to submarine cable work for amplifying the feeble current at'the receiving end the invention is of special imporsired. In general in the art of submarine,

land and wireless telegraphy, the invention is of importance with reference to recording, high-speed working and direct repetition from one type of system to another type of system.

What is claimed is:

1. The combination with a source of feeble electric currents, of a thermionic repeateryhaving an input circuit directly connected to said source of current and an output circuit of high voltage, and a second thermionic repeater having an output circuit of low impedance and having an input circuit directly connected to the output circuit of said first mentioned repeater.

2. The combination with a plurality of thermionic repeaters connected in tandem, the first repeater of the series having a, highvoltage output and the last repeater of the series having a high-current output.

3. The combination with an incoming and an outgoing line of low impedance, of a outgoing line.

4. The combination with a line of low impedance, of a current amplif ing means directly connected therewith, said amplifying means comprising a plurality of thermionic repeaters in tandem, the first ofsaid repeaters having a high-voltage output and the last of said repeaters having a hlgh-current output.

5. The combination with a repeater, of a plurality of vacuum discharge repeaters connected in multiple with the output circuit of said first mentioned repeater, said mentioned repeater having a high-voltage age output and said other repeaters each having a high-current output.

6. The combination with a thermionic repeater, of a plurality of thermionic repeaters connected in multiple into which said first mentioned repeater works, said first mentioned repeater having ahigh-voltage output and said other repeaters having a In witness whereof, I hereunto subscribe high-current output. my name this 25 day of May, A. D. 1914.

7. The combination of two thermionic repeater structures connected in tandem and HAROLD DE FOREST ARNOLD 5 having a common inclosing bulb, the first of Witnesses:

said structures having a high-vo1tage out- E. EDLER,

put and. the other a high-current output. K. L. STAHL.