US1913978A - Inductance and capacity - Google Patents

Description

June 13, 1933. H. A. EWEN INDUCTANGE AND CAPACITY Filed June 12, 1930 I I l I I II INVENTOR HARRY ALEXANDER EWEN BY ATfoRNEY Patented June 13, 1938 UNITED STATES "PATENT oFmc HARRY ALEXANDER WIN, OI snmnmn, ENGLAND, ASSIGNOB TO RADIO CORPORATION 01 AIIBIOA; A CORPORATION OF DELAWARE IIDUO'IAICI AND CAPACITY Application filed June II, 1080, lerlal Io. 40,588, and in Great Britain has 14, 1988.

This invention relates to inductances and cap acities for use with electrical resonant circuit arrangements, and has for its object to provide a correcting arrangement where by undesired changes of f temperature chan uency, due to in the e ements of an ordinary tuned circuit or the like, may be compensated.

Accordin to this invention undesired change of requency in the'elements of an ord inary tuned circuit or the like is compensated for by connecting-into or associating with said circuit an auxiliary inductance or ind uctances and/or a capacity or capacities which is or are so constructed as to vary with temperature to an extent necessary to com nsate for the variation in the constants of t e main inductance and condenser in the circuit to'be corrected.

Preferably the auxiliary device or devices is or are itself or themselves variable, i. e.

- is of the type wherein the capacity or inductance at a giventemperature may be varied.

The invention is illustrated in the accompanying drawing; in which:

Figure 1 shows a condenser constructed in accordance with the present invention,

Figures 2 and 3 show a modification'of the arrangement shown in Figure 1,

Fi ure 4 shows an open view 3 wit the closing removed,

of Figure Figure 5 shows acircuit arrangement including one of the capacities shown in Figures l to 4 inclusive.

Figure 6 shows an inductance of constant characteristics, while;

Figure 7 shows a modification of the at rangement of Fi re 6.

Referring to denser suitable for use denser for carryin into efiect, the sai pair of conductive as an-auxiliary conthe present invention "condenser comprises a plates a, 6, located opite .onev another, said lates being carried members whose cee ient of temperalgure 1 which shows a con-.

ture expansion is different. 'As shown, one plate is mounted upon a copper rod 0 or other rod having a relatively large temperature expansion coeflicient, while the other plate is mounted u on a frame (1 of silica or other material 0 relativel low temperature expansion coefficient. he late I) is fixed to the bottom of the pot-1i e carrier (1 of silica, while the copper rod passes throu h a fixing hole in a cross piece 0 car- 55 ried y the top of the carrier. The rod may be fixed in any desired position by means of a set-screw f. With this arrangement the capacity of the condenser will increase with temperature. If the opposite efiect is desired, the electrode fixed to the pot-like carrier may be arranged above the floor thereof or as shown in Figure 2 the floor may be omitted and the electrode fixed about mid-way along the wall. The electrode 6 is formed with a central hole through which the rod 0 carrying the other plate a passes, so that said other plate is on the side of the first plate remote from the cross piece. The arrangement thus described, though capable of capacity adjustment by moving the copper rod in the cross piece, is not convenient for tuning and is therefore most suitable for use in fixed tuned circuits. In a preferred construction shown in Figures 3 and 4 whereby variable capacity is ob-- tained, concentric arcuate plates are employed, one plate being fixed to the carrier 30 d of silica or the like and the copper rod carrying the other plate being arranged to be rotatable. The construction will be obvious from Figure 3. It will be seen that by rotating the rod 0 the capacity of the 35 condenser constituted by the arcuate plates will be varied. This arrangement is very suitable for correcting a circuit such as a 'wavemeter which can be tuned to difl'erent circuit is shown diagrammatically in Figure 5.

In the modification shown in Figure 6, which shows an inductance coil suitable for use in carrying out the invention a silica frame is employed to support one end of the coi h the other end being carried by a rod J of copper or the like arranged to be clamped in an desired position in the frame as shown. ith this construction increase in temperature. increases the value of the inductance.

Figure '3 illustrates a modification of the arrangement shown in Figure in which induc ance coils h are employed, one earned the frame 51 and the other i rod j, As shown any increase in iper-attire increases the mutual inductance csite eiiect may be obtained by arranging coils outside the silica frame and the rod j being passed throu h a suitable positioned hole in one wall 0 the frame i. e. by employing a construction analogous to that shown in Figure 2. It will be seen that the invention has the advantage that the main components of an oscillatory circuit to be corrected may be or standard desi n and constructed of materials which whilst givin rise to changes due to temperature variations, are convenient or cheap for manufacturing processes or have other advantages such as li htness or strength which are important or the purpose in view. It also enables an existing apparatus to be corrected where the requirements of service renders this necessar Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, i declare that what I claim is 1. A. temperature compensating reactance comprising asupporting member of silica, a reactance element, means for fastening said element at one terminal to said supporting member, metallic means, means for adjustably mounting said metallic means on said support, said metallic means having a co-eflicient of expansion different than the co-efiicient of expansion of said support member, and means for fastening the other terminal of said reactance element to said metallic means.

2. A temperature compensating reactance comprising a silica support, housing an inductive reacts'nce element, means for fasone terminal 01" said reactance to said silica supper"; housing member, metallic means adjustably mounted on said silica support housing, said last named metallic means havinga coeiiicient of expansion different than the coeflicient of expansion of the silica support housing, and means for fastening the other terminal of said inductive rcactance to said metallic means.

oesri'een it and 11' though obviously the opferent coefiicient of expansion than said first named support whereby the efi'ect of a v change in temperature on the physical character of-said reactant-e is compensated.

' 4:. A temperature compensating variable condenser comprising a silica support hous ing, a fixed arcuate electrode supported within said housing, outside coi'mecting means for said fixed electrode, movable arcucte electrode supported on one end of a metallic rod, said metallic rod being adiustably supported from said silica support .iousing.

HARRY ALEXANDER EWEN.

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