US3748618A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radio frequency choke
Assignee: Siemens AG
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Filing: 1972-04-17
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Granted: 1973-07-24
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Expires: 1992-04-17
Abstract
Abstract A radio frequency choke for reducing radio frequency interference in switching circuits as for example for gating bidirectional alternating current comprising a composite core with a first portion formed of ferrite material and a second portion formed of laminations of magnetic sheet material. The ferrite and laminated portions may be annular shaped and the radio frequency interference is substantially reduced if an air gap is provided in the ferrite core.
Inventors
- 👤 H Kaiserswerth
- 👤 V Seiler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:23
CPC Classifications
H; H04; H04B; H04B15/00; H04B15/02; H01; H01F; H01F27/00; H01F27/24; H01F27/245; H01F27/25; H01F27/255; H01F38/00; H01F38/02; H01F38/023; H01F3/00; H01F3/10; H01F2003/106
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
84 words
A radio frequency choke for damping radio frequency interference impulses generated by electronic switches such as silicon controlled rectifiers comprising: a core formed of two annular core portions which are axially superposed and upon which at least one winding is mounted, wherein one of said annular core portions is formed of magnetizable, non-alloyed sheet iron material and the other of said annular core portions is formed of ferrite material, and wherein an air gap is formed in said other of said annular core portions.
Claim 2
Dependent Claim
84 words
A radio frequency choke for damping radio frequency interference impulses generated by electronic switches such as silicon controlled rectifiers comprising: a core formed of two annular core portions which are axially superposed and upon which at least one winding is mounted, wherein one of said annular core portions is formed of magnetizable, non-alloyed sheet iron material and the other of said annular core portions is formed of ferrite material, and wherein an air gap is formed in said other of said annular core portions.
Claim 3
Dependent Claim
17 words
A radio frequency choke according to claim 1 wherein said iron material is deep-draw sheet iron material.
Claim 4
Dependent Claim
28 words
A radio frequency choke according to claim 1 wherein said one of said annular core portions is formed of a plurality of ring-shaped laminations of magnetizable iron material.
Claim 5
Dependent Claim
19 words
A radio frequency choke according to claim 1 wherein said air gap in said other core portion extends radially.
Claim 6
Dependent Claim
33 words
A radio frequency choke according to claim 1 wherein the ratio of the effective cross-sectional areas of said other core portion to said one core portion is not greater than one to one.
Claim 7
Dependent Claim
23 words
A radio frequency choke according to claim 1 wherein said air gap has a width within the range of 0.2 through 0.3 millimeters.
Claim 8
Dependent Claim
27 words
A radio frequency choke according to claim 6 wherein the outer diameter of said core is about 34 millimeters and the inner diameter is about 20 millimeters.
Claim 9
Dependent Claim
42 words
A radio frequency choke according to claim 6 wherein the height of said other core portion is about 3 millimeters and the ratio of the cross-sectional area of said other core portion to said one core portion is about one to three.
References Cited (Backward Citations)
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Cited
US1318787A
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DE644690C
Cited
US1910253A
Cited
US3170133A
Cited
US3423710A
Cited
DE1804835A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-23 | 1977-01-22 | 1977-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-23 | 1981-01-22 | 1981-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-23 | 1985-01-22 | 1985-07-24 | $7700.00 | Window Closed / Lapsed |