US3704434A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Skin effect rf bridge filter
Assignee: Individual
•
Filing: 1971-04-20
•
Granted: 1972-11-28
•
Expires: 1991-04-20
Abstract
Abstract A filter in a bridge configuration having different types of iron coated conductors. The device excludes current from a load by utilizing the skin effect to attenuate RF energy. The bridge is unbalanced at low frequencies allowing low frequency energy and direct current to pass relatively unhindered.
Inventors
- 👤 Donald A Schlachter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 00:56
CPC Classifications
H; H03; H03H; H03H1/00
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
115 words
A skin effect filter for excluding current from a load comprising: a load from which high frequency current is to be excluded; and a plurality of resistive elements connected in the form of a Wheatstone bridge with said load connected to diagonally opposite junctions of said bridge; each of said resistive elements comprising a central core of conductive material coated with a second conductive material; the central core of a first two opposed arms of said bridge having a higher resistance than the central core of a second two opposed arms; whereby the bridge is unbalanced at low frequencies and, due to the skin effect, balanced at high frequencies to exclude current from said load.
Claim 2
Dependent Claim
115 words
A skin effect filter for excluding current from a load comprising: a load from which high frequency current is to be excluded; and a plurality of resistive elements connected in the form of a Wheatstone bridge with said load connected to diagonally opposite junctions of said bridge; each of said resistive elements comprising a central core of conductive material coated with a second conductive material; the central core of a first two opposed arms of said bridge having a higher resistance than the central core of a second two opposed arms; whereby the bridge is unbalanced at low frequencies and, due to the skin effect, balanced at high frequencies to exclude current from said load.
Claim 3
Dependent Claim
36 words
The filter of claim 1 wherein the first two opposite resistive elements have a central core comprised of a nickel and chromium alloy; and the second two opposite resistive elements have a central core of copper.
Claim 4
Dependent Claim
18 words
The filter of claim 2 wherein the thickness of the conductive coating is equal to the skin depth.
Claim 5
Dependent Claim
13 words
The filter of claim 3 wherein the conductive coating is a ferromagnetic material.
Claim 6
Dependent Claim
11 words
The filter of claim 3 wherein the ferromagnetic material is iron.
Claim 7
Dependent Claim
12 words
The filter of claim 3 wherein the ferromagnetic material coating is nickel.
Claim 8
Dependent Claim
11 words
The filter of claim 3 wherein the ferromagnetic material is cobalt.
Claim 9
Dependent Claim
42 words
The filter of claim 1 wherein the resistive elements of the first two opposite arms are comprised of ferrite tubes; and the resistive elements of the second two opposite arms are comprised of ferrite tubes having a metal conductor through the center.
Claim 10
Dependent Claim
22 words
The filter of claim 1 wherein the resistive elements are constructed to have an equal resistance above a frequency of about 10KHz.
Claim 11
Dependent Claim
22 words
The filter of claim 8 wherein the load is an electroexplosive device whereby the filter provides protection from randomly induced RF energy.
Claim 12
Dependent Claim
59 words
The filter of claim 1 wherein the first two opposite resistive elements are comprised of a nickel and chromium alloy wire; and the second two opposite resistive elements are comprised of iron wire having a DC resistance equal to the first two opposite resistive elements whereby the bridge filter is balanced at low frequencies and unbalanced at high frequencies.
Claim 13
Dependent Claim
49 words
The filter of claim 1 wherein the resistive elements of the first two opposite arms are solid conductors; and the resistive elements of the second two opposite arms have an outer portion of the same material as the first two opposite arms and core of a second conductive material.
Claim 14
Dependent Claim
21 words
The filter of claim 12 wherein the resistive elements of the first two opposite armS are comprised of a nickel-iron alloy.
Claim 15
Dependent Claim
20 words
The filter of claim 13 wherein the core of the second two opposite arms have a core comprised of copper.
Claim 16
Dependent Claim
24 words
The filter of claim 1 wherein the core materials for the respective arms are selected to maintain a balanced bridge at an increased temperature.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-11-28 | 1976-05-29 | 1976-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-28 | 1980-05-29 | 1980-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-28 | 1984-05-29 | 1984-11-28 | $7700.00 | Window Closed / Lapsed |