Patent US4484251A successfully refreshed from Google Patents.
US4484251A
Expired / Lapsed
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Current restriction element responsive to applied voltage
Assignee: TDK Corp
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Filing: 1982-02-20
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Granted: 1984-11-20
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Expires: 2002-02-20
Abstract
Abstract A current restriction device for alternate circuit with small size, low producing cost and low power loss has been found by using a ferro-electric body with rectangular hysterisis characteristics. Said device is used for instance as a ballast for restricting current in a fluorescent lamp. Said ferro-electric body has main component of B a T i O 3 , additive of S r or P b for substitution of part of B a and Z n or S n for substitution of part of T i , and a mineralizer of M n o or C r2 O 3 . The voltage-current characteristics of said ferro-electric body show non-linearity that the impedance ratio (Z 2 /Z 1 ) of the impedance Z 2 measured with alternate field of 500 volts/mm to the impedance Z 1 measured with alternate field of 5 volts/mm is less than 1/10.
Inventors
- 👤 Sho Masujima
- 👤 Yoshishige Towatari
- 👤 Shoichi Iwaya
- 👤 Hitoshi Masumura
- 👤 Hisao Abe
- 👤 Norimasa Sakamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 01:53
CPC Classifications
H; H01; H01G; H01G7/00; H01G7/06; H01C; H01C7/00; H01C7/10; H01C7/105; H01C7/108; H01C7/115
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
76 words
A current restriction device responsive to an applied electric field comprising a ferro-electric polycrystalline ceramic with a main component of Barium-titanate (BaTiO 3 ), said device having a impedance ratio (Z 2 /Z 1 ) of less than 1/10 wherein Z 2 is the impedance of said device measured with an alternating electric field lower than 500 volts/mm, and Z 1 is the impedance of said device measured with an alternating electric field of 5 volts/mm.
Claim 2
Dependent Claim
76 words
A current restriction device responsive to an applied electric field comprising a ferro-electric polycrystalline ceramic with a main component of Barium-titanate (BaTiO 3 ), said device having a impedance ratio (Z 2 /Z 1 ) of less than 1/10 wherein Z 2 is the impedance of said device measured with an alternating electric field lower than 500 volts/mm, and Z 1 is the impedance of said device measured with an alternating electric field of 5 volts/mm.
Claim 3
Dependent Claim
107 words
A current restriction device responsive to an applied electric field comprising a ferro-electric polycrystalline ceramic with a main component of Barium-titanate (BaTiO 3 ), a first additive selected from Sr and Pb substituted for part of Ba of said Barium-titanate, a second additive selected from Zr and Sn for part of Ti of said Barium-titanate, said device having an impedance ratio (Z 2 /Z 1 ) of less than 1/10, wherein Z 2 is the impedance of said device measured with an alternating electric field lower than 500 volts/mm, and Z 1 is the impedance of said device measured with an alternating electric field of 5 volts/mm.
Claim 4
Dependent Claim
107 words
A current restriction device responsive to an applied electric field comprising a ferro-electric polycrystalline ceramic with a main component of Barium-titanate (BaTiO 3 ), a first additive selected from Sr and Pb substituted for part of Ba of said Barium-titanate, a second additive selected from Zr and Sn for part of Ti of said Barium-titanate, said device having an impedance ratio (Z 2 /Z 1 ) of less than 1/10, wherein Z 2 is the impedance of said device measured with an alternating electric field lower than 500 volts/mm, and Z 1 is the impedance of said device measured with an alternating electric field of 5 volts/mm.
Claim 5
Dependent Claim
30 words
A current restriction device according to claim 1 or claim 2 wherein the ratio of impurities except of said main component and said additives is less than 0.5 weight percent.
Claim 6
Dependent Claim
126 words
A current restriction device responsive to an applied electric field comprising a ferro-electric polycrystalline ceramic with a main component of Barium-titanate (BaTiO 3 ), a first additive selected from Sr and Pb substituted for part of Ba of said Barium-titanate, a second additive selected from Zr and Sn substituted for part of Ti of said Barium-titanate, a mineralizer of at least one of 0.005-0.3 weight % of Cr and 0.005-0.3 weight T of Mn, said device having an impedance ratio (Z 2 /Z 1 ) of less than 1/10, wherein Z 2 is the impedance of said device measured with an alternating electric field lower than 500 volts/mm, and Z 1 is the impedance of said device measured with an alternating electric field of 5 volts/mm.
Claim 7
Dependent Claim
126 words
A current restriction device responsive to an applied electric field comprising a ferro-electric polycrystalline ceramic with a main component of Barium-titanate (BaTiO 3 ), a first additive selected from Sr and Pb substituted for part of Ba of said Barium-titanate, a second additive selected from Zr and Sn substituted for part of Ti of said Barium-titanate, a mineralizer of at least one of 0.005-0.3 weight % of Cr and 0.005-0.3 weight T of Mn, said device having an impedance ratio (Z 2 /Z 1 ) of less than 1/10, wherein Z 2 is the impedance of said device measured with an alternating electric field lower than 500 volts/mm, and Z 1 is the impedance of said device measured with an alternating electric field of 5 volts/mm.
Claim 8
Dependent Claim
29 words
A current restriction device according to claim 4 wherein the ratio of impurities except of said main component, said additives, and said mineralizer is less than 0.5 weight percent.
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) | 1987-11-20 | 1988-05-21 | 1988-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-20 | 1992-05-21 | 1992-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-20 | 1996-05-21 | 1996-11-20 | $7700.00 | Window Closed / Lapsed |