US3348106A - Tubular condenser of variable capacity - Google Patents

Tubular condenser of variable capacity Download PDF

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Publication number
US3348106A
US3348106A US557792A US55779266A US3348106A US 3348106 A US3348106 A US 3348106A US 557792 A US557792 A US 557792A US 55779266 A US55779266 A US 55779266A US 3348106 A US3348106 A US 3348106A
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United States
Prior art keywords
tubular member
condenser
variable capacity
threaded spindle
tubular
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US557792A
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English (en)
Inventor
Vinz Ottmar
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Schott AG
Original Assignee
Jenaer Glaswerk Schott and Gen
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Filing date
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G5/00—Capacitors in which the capacitance is varied by mechanical means, e.g. by turning a shaft; Processes of their manufacture
    • H01G5/04—Capacitors in which the capacitance is varied by mechanical means, e.g. by turning a shaft; Processes of their manufacture using variation of effective area of electrode
    • H01G5/12—Capacitors in which the capacitance is varied by mechanical means, e.g. by turning a shaft; Processes of their manufacture using variation of effective area of electrode due to rotation of part-cylindrical, conical, or spherical electrodes

Definitions

  • the invention relates to a tubular condenser of variable capacity in which a tubular member is provided on its outer circumference with a stationary electrode which is arranged opposite a slidable electrode arranged in the interior of the tubular member.
  • the slidable electrode has the form of an axially adjustable piston which is mounted on an axially adjustable rod which may consist of a threaded spindle.
  • Such type of condensers are used among other fields also in the UHF range.
  • Condensers of this type are known which are constructed as ceramic or glass tube trimmer. Furthermore, such condensers have been used in which the dielectric comprises an organic material.
  • trimmer-type condensers are employed below 100 mHz. principally for a fine adjustment of circuits and in this type of use are suitably arranged in parallel to a condenser having a substantially greater capacity. In the case of higher frequencies, particularly above 100 mHz., these trimmer condensers are used directly for the construction of electric circuits, and in that case, they constitute exclusively the oscillatory circuit capacity. Furthermore, these condensers are used for resonance compensation of geometrically constructed oscillating systems, such as oscillating chambers, coaxial resonance lines, etc.
  • the requirements on the condenser are particularly high, especially concerning its loss tangent, since on one hand the loss capacity increases proportional with the operating frequency, while on the other hand at these high frequencies the requirements concerning the resonance sharpness and therewith the circuit quality are frequently particularly high.
  • the tubular condenser of variable capacity comprises a tubular member provided with an exterior layer and piston axially slidably mounted in the interior of said tubular member and serving as an inner layer.
  • the piston is axially adjusted by an axially extending threaded spindle which latter forms a path for the electric current to the piston, and this path is made shorter by changing the profile of the thread on the spindle.
  • FIG. 1 illustrates in a longitudinally axial section a tubular condenser of variable capacity
  • FIGS. 2 and 3 illustrate each, partially in section, a different threaded spindle which may be used in the condenser of the present invention.
  • FIG. 4 illustrates in cross-section still another example of a threaded spindle which may be used in the condenser of the present invention.
  • the condenser comprises a tubular member 5 made of a dielectric, such as glass, on one end of which is attached a mounting flange 1 provided With an exteriorly threaded mounting projection 1a and an interiorly threaded cylindrical projection 1b extending axially into the tubular member 5.
  • a threaded spindle 2 extends through the threaded projection 1b and carries on its inner end a piston 3 which slidably engages the inner wall of the tubular member 5 and forms the inner layer or electrode of the condenser.
  • the other electrode of the condenser is formed by an exterior layer 4 fixedly attached to the outer circumference of the tubular member 5.
  • the piston 3 Upon rotation of the threaded spindle 2, the piston 3 is axially adjusted within the tubular member 5 relatively to the stationary outer layer 4.
  • the thread of the spindle 2 has its crests removed to form a flattened helical perimeter 2a so as to make the thread profile trapezoidal, while according to FIG. 3 the root of the thread 2b on the spindle 201 is formed by flattened valleys 2e.
  • the selected shape of the profile of the thread reduces considerably the path for the electric current between the fiange 1 and the piston 3.
  • the threaded spindle 2c is provided with three circumferentially lengthwise or axially extending grooves 2h which have a radial depth extending down to the root diameter of the thread.
  • a tubular condenser of variable capacity comprising a dielectric in the form of a tubular member, an exterior electrode fixedly mounted on the outer circumference of said tubular member, a slidably mounted inner electrode within said tubular member, said slidable electrode comprising a piston axially slidably arranged in said tubular member and attached to an axially extending threaded spindle threadedly supported in a mounting flange at one end of said tubular member, the thread on said threaded spindle having flattened crests to have a trapezoidal profile which reduces at high frequencies the supply conductor resistance for the electric current passing from the spindle to the piston by reducing the length of the current path.
  • a condenser according to claim 1 in which the thread on the threaded spindle is provided with a plurality of lengthwise extending grooves.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Control Of Motors That Do Not Use Commutators (AREA)
  • Fixed Capacitors And Capacitor Manufacturing Machines (AREA)
US557792A 1965-06-16 1966-06-15 Tubular condenser of variable capacity Expired - Lifetime US3348106A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEJ28354A DE1229189B (de) 1965-06-16 1965-06-16 Trimmerkondensator

Publications (1)

Publication Number Publication Date
US3348106A true US3348106A (en) 1967-10-17

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ID=7203260

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Application Number Title Priority Date Filing Date
US557792A Expired - Lifetime US3348106A (en) 1965-06-16 1966-06-15 Tubular condenser of variable capacity

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US (1) US3348106A (en:Method)
DE (1) DE1229189B (en:Method)
NL (1) NL6607631A (en:Method)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3938012A (en) * 1974-01-28 1976-02-10 Standex International Corporation Variable capacitor

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2922093A (en) * 1957-01-22 1960-01-19 Jfd Electronics Corp Coaxial trimmer capacitors

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1883911U (de) * 1963-12-05 Steatit-Magnesia Aktiengesellschaft, Lauf/Pegnitz Vereinfachter Rohrtrimmer mit federnder Führung
DE1898992U (de) * 1964-06-08 1964-08-20 Christian Schwaiger Elektrotei Rohrtrimmerkondensator mit zweitem hilfsdielektrikum.

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2922093A (en) * 1957-01-22 1960-01-19 Jfd Electronics Corp Coaxial trimmer capacitors

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3938012A (en) * 1974-01-28 1976-02-10 Standex International Corporation Variable capacitor

Also Published As

Publication number Publication date
DE1229189B (de) 1966-11-24
NL6607631A (en:Method) 1966-12-19

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