US3885171A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thyristor element and circuit
Assignee: Blackwell Electronics Ind Co Ltd
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Filing: 1971-11-03
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Granted: 1975-05-20
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Expires: 1991-11-03
Abstract
Abstract The radio noise generated by a thyristor circuit is reduced by extending the turn-on time. A condenser is connected between the gate and cathode electrodes of the thyristor, which is so constructed that it has an equivalent circuit including a PNP transistor, an NPN transistor and three resistors, connected respectively between the base of the PNP transistor and the collector of the NPN transistor, the base of the NPN transistor and the collector of the PNP transistor, and the collector of the NPN transistor and the anode terminal of the thyristor. The time constant of the condenser with the equivalent resistors establishes the turn-on delay. An application of the invention in a lamp dimming circuit is disclosed.
Inventors
- 👤 Akira Hirono
- 👤 Masayoshi Miyajima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 17:28
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/16; H03K17/51; H03K17/56; H03K17/72; H03K17/725
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
203 words
A semi-conductor circuit comprising: a thyristor having a gate electrode, an anode electrode, and a cathode electrode; and circuit means comprising a condenser connected between said gate electrode and said cathode electrode for preventing abrupt buildup of current flow through said thyristor and thereby reducing the generation of radio noise upon turn-on of said thyristor by extending the turn-on time of said thyristor, said thyristor being so constructed that it has an equivalent circuit including an NPN transistor and a PNP transistor, the collector of said NPN transistor being connected to the emitter of said PNP transistor through a first equivalent resistor, the collector of said NPN transistor being connected through a second equivalent resistor to the base electrode of said PNP transistor, the collector of said PNP transistor being connected to the base of said NPN transistor through a third equivalent resistor, said emitter of said PNP transistor serving as said anode electrode, said collector of said PNP transistor serving as said gate electrode, and said emitter of said NPN transistor serving as said cathode electrode, and said condenser and said first, second, and third equivalent resistors establishing a time constant which causes substantial delay in the turn-on time of said thyristor.
Claim 2
Dependent Claim
203 words
A semi-conductor circuit comprising: a thyristor having a gate electrode, an anode electrode, and a cathode electrode; and circuit means comprising a condenser connected between said gate electrode and said cathode electrode for preventing abrupt buildup of current flow through said thyristor and thereby reducing the generation of radio noise upon turn-on of said thyristor by extending the turn-on time of said thyristor, said thyristor being so constructed that it has an equivalent circuit including an NPN transistor and a PNP transistor, the collector of said NPN transistor being connected to the emitter of said PNP transistor through a first equivalent resistor, the collector of said NPN transistor being connected through a second equivalent resistor to the base electrode of said PNP transistor, the collector of said PNP transistor being connected to the base of said NPN transistor through a third equivalent resistor, said emitter of said PNP transistor serving as said anode electrode, said collector of said PNP transistor serving as said gate electrode, and said emitter of said NPN transistor serving as said cathode electrode, and said condenser and said first, second, and third equivalent resistors establishing a time constant which causes substantial delay in the turn-on time of said thyristor.
Claim 3
Dependent Claim
110 words
A semi-conductor circuit as recited in claim 1, further comprising a source of alternating current power, a load, said load being connected between one side of said source and said anode electrode, the other side of said source being connected to said cathode electrode, and a control circuit for said thyristor including a variable resistor and a capacitor connected in series between said anode and cathode electrodes and a breakdown element connected between the junction between said variable resistor and said capacitor and said gate electrode, whereby a trigger pulse is applied to said gate electrode when the charge on said capacitor reaches the breakdown voltage of said breakdown element.
Claim 4
Dependent Claim
15 words
A semi-conductor circuit as recited in claim 2, wherein said breakdown element comprises a DIAC.
Claim 5
Dependent Claim
26 words
A semi-conductor circuit as recited in claim 2, wherein said load is a lighting load and said circuit is a dimming circuit for said lighting load.
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) | 1978-05-19 | 1978-11-18 | 1979-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-19 | 1982-11-18 | 1983-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-19 | 1986-11-18 | 1987-05-20 | $7700.00 | Window Closed / Lapsed |