US3983449A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Discharge lamp ballast circuits
Assignee: EMI Group Ltd
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Filing: 1975-11-24
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Granted: 1976-09-28
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Expires: 1995-11-24
Abstract
Abstract A ballast circuit for a discharge lamp uses simply a capacitor in series with a relatively small inductor the capacitative reactance being between 24 and 55 times the inductive reactance. At these values the third harmonic distortion is unexpectedly low, while the crest factor (ratio of peak to r.m.s. current) is still within acceptance values. Because the inductor is small the efficiency of the circuit is high, and its cost and weight reduced. The capacitance/inductance ratio can be equated to the ratio of the frequency of the tuned circuit to the supply frequency, and on this basis the preferred range is defined by 5 to 71/2 times supply frequency.
Inventors
- 👤 Peter Adrian Dear
- 👤 Wladyslaw Pelc
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 02:02
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/02; H05B41/04; Y; Y10; Y10S; Y10S315/00; Y10S315/05
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
58 words
In a discharge lamp circuit comprising an a.c. supply, and a discharge lamp, a ballast consisting of a capacitor and an inductor connected in series between the supply and the lamp, the ratio of capacitative reactance provided by the capacitor to inductive reactance provided by the inductor being from about 24 to about 55 at the supply frequency.
Claim 2
Dependent Claim
58 words
In a discharge lamp circuit comprising an a.c. supply, and a discharge lamp, a ballast consisting of a capacitor and an inductor connected in series between the supply and the lamp, the ratio of capacitative reactance provided by the capacitor to inductive reactance provided by the inductor being from about 24 to about 55 at the supply frequency.
Claim 3
Dependent Claim
17 words
A circuit according to claim 1, wherein the said ratio has a lower limit of about 26.
Claim 4
Dependent Claim
17 words
A circuit according to claim 1, wherein the said ratio has a lower limit of about 29.
Claim 5
Dependent Claim
17 words
A circuit according to claim 1, wherein the said ratio has an upper limit of about 50.
Claim 6
Dependent Claim
17 words
A circuit according to claim 1, wherein the said ratio has an upper limit of about 45.
Claim 7
Dependent Claim
17 words
A circuit according to claim 1, wherein the said ratio has an upper limit of about 40.
Claim 8
Dependent Claim
17 words
A circuit according to claim 1, wherein the said ratio is from about 29 to about 40.
Claim 9
Dependent Claim
13 words
A circuit according to claim 1, wherein the said ratio is about 37.
Claim 10
Dependent Claim
59 words
In a discharge lamp circuit comprising an a.c. supply, and a discharge lamp, a ballast consisting of a capacitor and an inductor connected in series between the supply and the lamp, and providing a tuned circuit, the ratio of the frequency of the tuned circuit to the supply frequency lying in the range of about 5 to about 71/2.
Claim 11
Dependent Claim
59 words
In a discharge lamp circuit comprising an a.c. supply, and a discharge lamp, a ballast consisting of a capacitor and an inductor connected in series between the supply and the lamp, and providing a tuned circuit, the ratio of the frequency of the tuned circuit to the supply frequency lying in the range of about 5 to about 71/2.
Claim 12
Dependent Claim
17 words
A circuit according to claim 8, wherein the said ratio has a lower limit of about 51/2.
Claim 13
Dependent Claim
17 words
A circuit according to claim 8, wherein the said ratio has an upper limit of about 61/4.
Claim 14
Dependent Claim
51 words
In a discharge lamp circuit comprising an a.c. supply, and a discharge lamp, a ballast consisting of a capacitor and an inductor connected in series between the supply and the lamp, and providing a tuned circuit tuned to a frequency in the range of about 300 Hz to about 450 Hz.
Claim 15
Dependent Claim
51 words
In a discharge lamp circuit comprising an a.c. supply, and a discharge lamp, a ballast consisting of a capacitor and an inductor connected in series between the supply and the lamp, and providing a tuned circuit tuned to a frequency in the range of about 300 Hz to about 450 Hz.
Claim 16
Dependent Claim
18 words
A circuit according to claim 11, wherein the said range has a lower limit of about 330 Hz.
Claim 17
Dependent Claim
18 words
A circuit according to claim 11, wherein the said range has an upper limit of about 375 Hz.
References Cited (Backward Citations)
US2056629A
Cited
US2170447A
Cited
US2256224A
Cited
US2351499A
Cited
US2695375A
Cited
US2482894A
Cited
US3781597A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-09-28 | 1980-03-29 | 1980-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-28 | 1984-03-29 | 1984-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-28 | 1988-03-29 | 1988-09-28 | $7700.00 | Window Closed / Lapsed |