US3908131A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control circuit having load and power source isolation
Assignee: 3M Co
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Filing: 1974-01-04
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Granted: 1975-09-23
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Expires: 1994-01-04
Abstract
Abstract A single proportional type control unit having a gated semiconductor switching device controlled by a single condition responsive impedance can be connected to one or more loads or to one or more power sources. Diodes are arranged to provide load and power source isolation. The circuit, for example, is connected in a traffic light control system to control the intensity of more than one lamp in a single traffic signal face for a traffic phase having more than one traffic signal face. One circuit provides control of the intensity of the lamps for onehalf of each cycle of the A.C. source connected to the control circuit. A modified circuit provides full cycle control of the lamps connected to the control circuit. The condition responsive impedance for such use is light responsive.
Inventors
- 👤 William J E Anton
- 👤 John E Collins
- 👤 Peter A Lind
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:59
CPC Classifications
G; G08; G08G; G08G1/00; G08G1/09; G08G1/095
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
121 words
An alternating current control circuit for connection in series with each of a plurality of loads and a common circuit neutral to control current flow to the plurality of loads comprising: a circuit portion including a gated semiconductor switching device and a gating circuit having a variable impedance connected to gate said switching device for controlling current flow through said circuit portion; and a plurality of sets of two, like poled, series connected unidirectional devices, one set for each load, said sets poled in the same direction and connected in parallel across said circuit portion, each of said sets providing a separate load connecting point for the control circuit, said connecting point being intermediate the two unidirectional devices of the set.
Claim 2
Dependent Claim
121 words
An alternating current control circuit for connection in series with each of a plurality of loads and a common circuit neutral to control current flow to the plurality of loads comprising: a circuit portion including a gated semiconductor switching device and a gating circuit having a variable impedance connected to gate said switching device for controlling current flow through said circuit portion; and a plurality of sets of two, like poled, series connected unidirectional devices, one set for each load, said sets poled in the same direction and connected in parallel across said circuit portion, each of said sets providing a separate load connecting point for the control circuit, said connecting point being intermediate the two unidirectional devices of the set.
Claim 3
Dependent Claim
145 words
An alternating current control circuit for connection in series with each of a plurality of loads for controlling current flow to the plurality of loads comprising: a circuit portion including a gated semiconductor switching device and a gating circuit having a variable impedance connected to gate said switching device for controlling current flow through said circuit portion; and a plurality of sets of two, like poled, series connected unidirectional devices, one set for each load plus another set, said sets poled in the same direction and connected in parallel across said circuit portion, each of said sets providing a separate connecting point, said connecting point for each set being intermediate the two unidirectional devices of the set, said connecting point of said another set providing a common connection for the control circuit with the remaining connecting points providing load connecting points for the control circuit.
Claim 4
Dependent Claim
145 words
An alternating current control circuit for connection in series with each of a plurality of loads for controlling current flow to the plurality of loads comprising: a circuit portion including a gated semiconductor switching device and a gating circuit having a variable impedance connected to gate said switching device for controlling current flow through said circuit portion; and a plurality of sets of two, like poled, series connected unidirectional devices, one set for each load plus another set, said sets poled in the same direction and connected in parallel across said circuit portion, each of said sets providing a separate connecting point, said connecting point for each set being intermediate the two unidirectional devices of the set, said connecting point of said another set providing a common connection for the control circuit with the remaining connecting points providing load connecting points for the control circuit.
Claim 5
Dependent Claim
161 words
A control circuit for controlling current flow to a load from a plurality of power sources having a common neutral comprising: a circuit portion for connection in series with the load including a gated semiconductor switching device for controlling the current flow through the circuit portion and a gating circuit having a variable impedance connected to gate said semiconductor switching device; and a plurality of sets of two, like poled, series connected, unidirectional devices one set for each power source, plus another set, said sets poled in the same direction and connected in parallel across said circuit portion and the series connected load, each of said sets providing a separate connecting point for the control circuit, said connecting point for each set being intermediate the two unidirectional devices of the set, said connecting points of said another set provided for connection to the common neutral of the power sources with the remaining connecting points so provided being power source connecting points.
Claim 6
Dependent Claim
161 words
A control circuit for controlling current flow to a load from a plurality of power sources having a common neutral comprising: a circuit portion for connection in series with the load including a gated semiconductor switching device for controlling the current flow through the circuit portion and a gating circuit having a variable impedance connected to gate said semiconductor switching device; and a plurality of sets of two, like poled, series connected, unidirectional devices one set for each power source, plus another set, said sets poled in the same direction and connected in parallel across said circuit portion and the series connected load, each of said sets providing a separate connecting point for the control circuit, said connecting point for each set being intermediate the two unidirectional devices of the set, said connecting points of said another set provided for connection to the common neutral of the power sources with the remaining connecting points so provided being power source connecting points.
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) | 1978-09-22 | 1979-03-24 | 1979-09-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-22 | 1983-03-24 | 1983-09-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-22 | 1987-03-24 | 1987-09-23 | $7700.00 | Window Closed / Lapsed |