US4021760A
Expired / Lapsed
US
⏱️ 0.0 years remaining
EMP circuit board filter using MOV devices
Assignee: United States Department of the Army
•
Filing: 1976-01-19
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Granted: 1977-05-03
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Expires: 1996-01-19
Abstract
Abstract Two partial circular chips of metal oxide varistor (MOV) material are moud in a TO-5 transistor case. Each chip acts as a capacitive element to ground for a low pass pi-filter network. An inductance, whose value is chosen for the required filter impedance and cut off frequency, is placed across the MOV chips and connected to TO-5 contacts, along with the MOV, completing the filter network. At normal signal levels, the package acts as a normal low-pass pi-filter network. At higher signal levels and transients, the bipolar MOV components clamp the voltage to a given level, determined by the MOV material grain structure and chip thickness.
Inventors
- 👤 Morris Campi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:56
CPC Classifications
H; H02; H02H; H02H9/00; H02H9/005; H02H9/04; H02H9/044; H03; H03H; H03H1/00; H03H7/00; H03H7/01
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
125 words
A filter for protecting circuits from over-voltage surges, the filter comprising: supporting means for mounting filter components thereon wherein the supporting means includes a planar shoulder for mounting; a plurality of MOV segments mounted on the planar shoulder, the segments positioned in spaced relation to each other to create respective capacitances for the filter; at least one inductance mounted on the planar shoulder, adjacent the MOV segments; electrodes attached to the supporting means and extending outwardly therefrom; and means for connecting the MOV segments and the inductance to preselected electrodes for completing a filter configuration therebetween wherein the connecting means include two outwardly extending leads from the inductance to a first and second preselected electrodes and includes leads connecting each segment with a preselected electrode.
Claim 2
Dependent Claim
125 words
A filter for protecting circuits from over-voltage surges, the filter comprising: supporting means for mounting filter components thereon wherein the supporting means includes a planar shoulder for mounting; a plurality of MOV segments mounted on the planar shoulder, the segments positioned in spaced relation to each other to create respective capacitances for the filter; at least one inductance mounted on the planar shoulder, adjacent the MOV segments; electrodes attached to the supporting means and extending outwardly therefrom; and means for connecting the MOV segments and the inductance to preselected electrodes for completing a filter configuration therebetween wherein the connecting means include two outwardly extending leads from the inductance to a first and second preselected electrodes and includes leads connecting each segment with a preselected electrode.
Claim 3
Dependent Claim
32 words
The subject matter set forth in claim 1 wherein two MOV segments are positioned in coplanar spaced relationship to each other for creating two capacitances with respect to a grounded supporting means.
Claim 4
Dependent Claim
27 words
The subject matter set forth in claim 2 wherein the inductance is a discrete inductor electrically connected between the MOV segments for creating a low pass pi-filter.
Claim 5
Dependent Claim
16 words
The subject matter set forth in claim 3 wherein the supporting means comprises a TO-5 package.
Claim 6
Dependent Claim
25 words
The subject matter set forth in claim 4 together with a Hi-Hat can positioned over the MOV segments and the inductor for encapsulated protection thereof.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-02 | 1980-11-01 | 1981-05-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-02 | 1984-11-01 | 1985-05-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-02 | 1988-11-01 | 1989-05-03 | $7700.00 | Window Closed / Lapsed |