US3903476A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Triggering means for silicon controlled rectifier circuit
Assignee: Skil Corp
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Filing: 1974-07-15
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Granted: 1975-09-02
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Expires: 1994-07-15
Abstract
Abstract The circuit for controlling the power supplied to a load from an alternating source in which a silicon control rectifier is connected in series with the source and the load. The particular silicon control rectifier used is one in which the impedance between the cathode and the gate is sufficiently high so that a simple RC firing circuit can be connected to the gate and the capacitor charged periodically to a value sufficient to effect conduction of the SCR.
Inventors
- 👤 Alex F Gawron
- 👤 Louis J Vassos
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:34
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/285; H02P7/292; H02P7/295; H02M; H02M1/00; H02M1/08; H02M1/081
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
237 words
A power control circuit comprising: a pair of terminals for connection to an alternating current source; a semiconductor controlled conducting device having a high cathode to gate resistance, anode and cathode electrodes and a gate means; means for connecting one of said electrodes to one of said terminals; means for connecting the other of said electrodes to one side of a load; means for connecting the other side of the load to the other of said terminals; a capacitor connected from said gate means to said cathode electrode; a charging circuit for said capacitor comprising a resistive voltage divider connected between said anode and cathode electrodes and an adjustable resistor connected to an intermediate point on said voltage divider; means for adjusting the voltage at the intermediate point on said voltage divider; said power control circuit including an electrically insulating substrate and wherein said voltage divider and said adjustable resistor are formed in spaced locations on said substrate and further including a movable wiper having first and second contact points spaced from each other a distance sufficient to permit one to engage a portion of either said voltage divider or a portion of said adjustable resistor but insufficient to permit both of said contact points to engage said voltage divider and said adjustable resistor simultaneously so as to permit adjustment of the voltage at the intermediate point of said voltage divider and adjustment of said adjustable resistor.
Claim 2
Dependent Claim
237 words
A power control circuit comprising: a pair of terminals for connection to an alternating current source; a semiconductor controlled conducting device having a high cathode to gate resistance, anode and cathode electrodes and a gate means; means for connecting one of said electrodes to one of said terminals; means for connecting the other of said electrodes to one side of a load; means for connecting the other side of the load to the other of said terminals; a capacitor connected from said gate means to said cathode electrode; a charging circuit for said capacitor comprising a resistive voltage divider connected between said anode and cathode electrodes and an adjustable resistor connected to an intermediate point on said voltage divider; means for adjusting the voltage at the intermediate point on said voltage divider; said power control circuit including an electrically insulating substrate and wherein said voltage divider and said adjustable resistor are formed in spaced locations on said substrate and further including a movable wiper having first and second contact points spaced from each other a distance sufficient to permit one to engage a portion of either said voltage divider or a portion of said adjustable resistor but insufficient to permit both of said contact points to engage said voltage divider and said adjustable resistor simultaneously so as to permit adjustment of the voltage at the intermediate point of said voltage divider and adjustment of said adjustable resistor.
Claim 3
Dependent Claim
47 words
The power control circuit of claim 1 wherein said voltage divider includes two separate resistance sections and said adjustable resistor includes a single resistance section and said wiper includes a third contact point mounted closer to one of said first and second contact points than the other.
Claim 4
Dependent Claim
25 words
The power control circuit of claim 1 wherein said voltage divider includes two separate resistance sections and said adjustable resistor includes two separate resistance sections.
Claim 5
Dependent Claim
146 words
In a power tool having a driving motor and an actuating element, the improvement comprising a control circuit for said motor including a controllable semiconductor switching device having a control element connected in series with said motor and having means for connections to a power source, a capacitor connected to said control element effective to determine the conduction thereof when charged to a predetermined voltage, a charging circuit for said capacitor including a voltage divider having means for connection to the power source, a resistor connected from said voltage divider to said capacitor, an electrically insulating substrate supporting said voltage divider and said resistor-spaced positions and a movable wiper having first and second spaced contact points engageable with said voltage divider and said adjustable resistor and a mechanical connection to said actuating element so as to be moved in response to movement of said actuating element.
Claim 6
Dependent Claim
146 words
In a power tool having a driving motor and an actuating element, the improvement comprising a control circuit for said motor including a controllable semiconductor switching device having a control element connected in series with said motor and having means for connections to a power source, a capacitor connected to said control element effective to determine the conduction thereof when charged to a predetermined voltage, a charging circuit for said capacitor including a voltage divider having means for connection to the power source, a resistor connected from said voltage divider to said capacitor, an electrically insulating substrate supporting said voltage divider and said resistor-spaced positions and a movable wiper having first and second spaced contact points engageable with said voltage divider and said adjustable resistor and a mechanical connection to said actuating element so as to be moved in response to movement of said actuating element.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-01 | 1979-03-03 | 1979-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-01 | 1983-03-03 | 1983-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-01 | 1987-03-03 | 1987-09-02 | $7700.00 | Window Closed / Lapsed |