US3919661A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic monitoring system with delayed activation
Assignee: Individual
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Filing: 1974-11-13
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Granted: 1975-11-11
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Expires: 1994-11-13
Abstract
Abstract A contactless motion detector, comprising an output thyristor controlled by a switching network, has an oscillator coupled to the switching network via a pre-amplifier. The oscillator and the pre-amplifier are energized from a source of pulsating direct current via a supply circuit which is part of the switching network and includes a constant-current unit in parallel with the output thyristor. To prevent untimely switching of the thyristor when power is connected to the system, a delay unit retards the energization of the pre-amplifier until the oscillator has reached its operating condition. The delay unit may include one or more semiconductive devices, such as cascaded transistors or diodes, connected across a capacitor of a resistive/capacitive series circuit which bridges a smoothing capacitor inserted between a pair of bus bars.
Inventors
- 👤 Robert Buck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:19
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/94; H03K17/945; H03K17/95; H03K17/9502; H03K17/28; H03K17/292; H03K17/951; H03K17/952; H03K17/9537; H03K17/9542; H03K17/9547
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
134 words
An electronic monitoring system comprising: detector means sensitive to an ambient condition for generating an output signal varying with a change in said condition, said detector means including a sensing stage and an amplifier stage coupled thereto; a supply circuit including a source of direct current and a current-responsive load; electronic switch means in circuit with said load controlled by said detector means for modifying the flow of current through said load in response to changes in said output signal; conductor means leading from said supply circuit to said detector means for energizing same; and delay means inserted between said conductor means and said amplifier stage for retarding the operation thereof upon activation of said supply circuit until said sensing stage has reached an operative condition, thereby preventing premature actuation of said switch means.
Claim 2
Dependent Claim
134 words
An electronic monitoring system comprising: detector means sensitive to an ambient condition for generating an output signal varying with a change in said condition, said detector means including a sensing stage and an amplifier stage coupled thereto; a supply circuit including a source of direct current and a current-responsive load; electronic switch means in circuit with said load controlled by said detector means for modifying the flow of current through said load in response to changes in said output signal; conductor means leading from said supply circuit to said detector means for energizing same; and delay means inserted between said conductor means and said amplifier stage for retarding the operation thereof upon activation of said supply circuit until said sensing stage has reached an operative condition, thereby preventing premature actuation of said switch means.
Claim 3
Dependent Claim
48 words
A system as defined in claim 1 wherein said sensing stage comprises an oscillator with a normal operating amplitude diminishing upon the development of a condition to be detected, said amplifier stage converting said amplitude into a normally small output signal increasing upon a diminution of said amplitude.
Claim 4
Dependent Claim
34 words
A system as defined in claim 2 wherein said electronic switch means comprises a thyristor with an input circuit including a switching transistor connected to said amplifier stage for energization by said output signal.
Claim 5
Dependent Claim
42 words
A system as defined in claim 3 wherein said supply circuit includes a constant-current unit in parallel with said thyristor and a capacitor in series with said constant-current unit, said conductor means comprising a pair of bus bars connected across said capacitor.
Claim 6
Dependent Claim
17 words
A system as defined in claim 4, further comprising a Zener diode in shunt with said capacitor.
Claim 7
Dependent Claim
26 words
A system as defined in claim 1 wherein said delay means comprises a resistive/capacitive circuit and semi-conductor means connected across a capacitive branch of said circuit.
Claim 8
Dependent Claim
15 words
A system as defined in claim 6 wherein said semiconductor means comprises a Zener diode.
Claim 9
Dependent Claim
18 words
A system as defined in claim 6 wherein said semiconductor means comprises a plurality of diodes in series.
Claim 10
Dependent Claim
17 words
A system as defined in claim 6 wherein said semiconductor means comprises a plurality of cascaded transistors.
Claim 11
Dependent Claim
29 words
A system as defined in claim 9 wherein said transistors are connected in a Darlington chain, further comprising a complementary transistor coupled to the last transistor of said chain.
References Cited (Backward Citations)
US3459961A
Cited
US3747010A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-10 | 1979-05-12 | 1979-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-10 | 1983-05-12 | 1983-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-10 | 1987-05-12 | 1987-11-11 | $7700.00 | Window Closed / Lapsed |