US1291106A - Electrical resistance. - Google Patents

Description

J. H. PAYNE. ELECTRICAL RESISTANCE. APPLICATION FILED NOV. 2:. 1911.

1,291, 106. atented Jan. 14, 1919.

Inventor 5 John HPagne,

b H is Atorneg.

com; 11. PAYNE,

OF'BALLSTON SPA, NEW YORK, ASSIGNOR T0 GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

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Specification of Letters I'atent.

Patented Jan. 14,1919.

Application filed November 21, 1917. Serial Io. 208,071.

To all 'whom it may concern: Be it known that I, JOHN H. PAYNE, a citizen of the United States, residing at Ballston Spa, in the county of Saratoga, State of New York, have invented certain new and" useful Improvements in Electrical Resistances, of which-the following is a specification.

The present invention'comprises a novel resistance unit which is particularly sultable for use in receiving systems for wireless telegraphy, particularly in amplifying systems or and instances when a unit of constant known."high resistance is desired.

In accordance with my invention a film of conducting material is deposited in a 0d vacuumupon the-inner surface of a sealed bulb and good electrical connections with leading-in conductors are provided by means of more conducting localized deposits of metal films adjacent the leadmg-in conductors. My invention includes both a procand a new article of manufacture,

The novel features of my invention are set forth with particularity in the appended claims. For a better understanding of my invention, reference may be had to the ap pended drawings taken in connection with the accompanying description.

Figure 1 is a sectional view of the resistance' unit in the first stage of manufacture; Fig. 2 is a sectional view of the unit provided with localized terminal films at the ends of the inclosing bulb, and 3 is a sectional view of the completed unit.

As shown in Fig. 1 the unit consists of.

an elongated bulb 1 consisting of glass, or

other suitable non-conducting material. In-

this bulb is mounted a metal holder 2, one end of which is sealed the wall of the container 1, and which-1s. specially bent near the sealed-in end to touch the wall of of the container 1. Near the ends of the filament 3 are wound short sections 5 and 6 of some material of relatively lower volatility than the filament- 3, for example, co

per, nickel, silver, or suitable alloys. t

I the end of the container 1, opposite the end into which the holder 2 is sealed, there is provided another leading-in conductor. 7 sealed into the wall of the container and having a section bent so as to" be in close contact with the wall of the container near the end. v

With the 'tube thus assembled a, vacuum is produced in the containeiggn" bulb being heated during exhaustion and the same degree of care being exercised'as- .i good practice inthe exhaustion of candescent'lamps. Preferably the highes vacuum attainable with the use of the mos eflicient pumps such as the condensation pump or the molecular pump, is produced in the bulb.

A heating current is passed through the filament 3 through the holder 2, leading-in wire 4, until the metal bodies 5 and 6 are vaporized by the heat generated in the filaments. The metal vapor is deposited locally at the ends of the bulb 1, asindicated in Fig. 2. The heating current is then in- 7 creased until-the filament itself is more or less volatilized as may be desired. The

volatilized metal is deposited by a closely adherent filament upon the" surface of the bulb, a good electrical connection being established by its deposition upon the already deposited metal filament at the ends of the bulbs.

By properly proportioning the 'bulb andadjustlng the length of time that the. thermal evaporation of the filament is continued and the temperature at which the evaporation is carried on, the thickness of the resistance filamentmay be easil predetermined. This'isnot possible in the liquid or paste type of high resistances formerly used. When preparing the conducting film allowance must be made for the temperature coeflicient of the deposited film. In practice, the resistance is observed during forming and .the' deposition is stopped at such pointthat the film when cooled to room temperatures willhave the desired resistance. This precaution is only necessary as the forming temerature wlth a highly incandescent filament is several hun e degrees above room temperature.

As shown in Fi 3, the completed unit is preferably provi ed-with 'conduc caps 8 and 9 contacting with the leading-m con (luctors 4 and 7, and held in position by a body of cement 10 filling the space between the ends of the tube and terminal caps.

As the described resistances remain at their constant predetermined value during use and do not polarize, they are superior to the various forms of higher resistance now in use.

Although resistance units embodying my invention may be manufactured to have almost any desired resistance, from a few ohms upward, my invention is more particularly applicable to units of small current carrying capacity having resistances somewhere within the range of about 25,000 ohms to 20 megohms.

WVhat Iclaim as new and desire to secure by Letters Patent of the United States, is

1. An electrical resistance unit comprising a sealed non-conducting container, current conductors sealed into said container, a film of refractory conducting material upon the inner surface of said container, and localized films of conducting material contacting both with said conductors and said film.

2. An electrical resistance unit comprising an evacuated glass tube, current conductors sealed into said tube, a film of refractory metal located upon the inner surface of said tube, and areas of good conducting material contacting with said conductors and said film, at the ends only and with said current conductors.

3. An electrical resistance unit comprising an evacuated glass. tube, leading-in c0nductors sealed into the ends of said tube,- a film of molybdenum located upon the inner surface of said tube intermediate said conductors and localized films of copper at the ends of said tube contacting with said molybdenum film and said conductors.

4. An electrical resistance unit comprising a sealed container of insulating material, a gas-free film of conducting material deposited on the inner surface of said container by evaporation in an inclosed space, means for contacting with said film at two separated points and leading in conductors joined to said contacting means. a 5. The process of making electrical resistance units which consists in evaporating within an evacuated glass tube and near the ends thereof, a body of metal sufficient in amount to produce a localized film, and then thermally evaporating a filament of refractory metal located to deposit a continuous film of metal upon the inner surface of said tube connecting said first-deposited, locali zed films of. metal.

In witness whereof, I have hereunto setmy hand this 5th day of November, 1917.

JOHN H. PAYNE.

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