US3787740A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Delay timer
Assignee: United States Department of the Navy
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Filing: 1972-10-04
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Granted: 1974-01-22
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Expires: 1992-10-04
Abstract
Abstract An electronic timer providing an accurate time delay comprising two oppositely charged capacitors connected in series with a resistor. One capacitor is smaller than the other and upon having the series circuit closed, it receives charge from the other capacitor. Upon passing through zero volts, an SCR is triggered setting off a squib.
Inventors
- 👤 F Salton
- 👤 A Silverstein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:44
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/28; H03K17/292
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
152 words
A time delay circuit comprising: a supply source; a first capacitor coupled to, and positively charged by said source; a second capacitor coupled to, and negatively charged by said source, said first capacitor having a capacitance several times larger than said second capacitor, said first capacitor charged in series with said second capacitor; a resistor coupled between said first capacitor and said second capacitor; said source coupled between said first capacitor and second capacitor to form a series charging circuit to provide the oppositely charged capacitors; a diode coupled across said second capacitor, a silicon controlled rectifier coupled to said diode, whereby said diode conducts when said second capacitor turns positive due to discharge of said first capacitor, allowing said silicon controlled rectifier to conduct, and means including a positively charged capacitor coupled to the anode of said silicon controlled rectifier to prevent conducting of said rectifier prior to said diode conducting.
Claim 2
Dependent Claim
152 words
A time delay circuit comprising: a supply source; a first capacitor coupled to, and positively charged by said source; a second capacitor coupled to, and negatively charged by said source, said first capacitor having a capacitance several times larger than said second capacitor, said first capacitor charged in series with said second capacitor; a resistor coupled between said first capacitor and said second capacitor; said source coupled between said first capacitor and second capacitor to form a series charging circuit to provide the oppositely charged capacitors; a diode coupled across said second capacitor, a silicon controlled rectifier coupled to said diode, whereby said diode conducts when said second capacitor turns positive due to discharge of said first capacitor, allowing said silicon controlled rectifier to conduct, and means including a positively charged capacitor coupled to the anode of said silicon controlled rectifier to prevent conducting of said rectifier prior to said diode conducting.
Claim 3
Dependent Claim
31 words
A time delay device as recited in claim 1 further including at least one zener diode connected across said resistor; and a voltage divider connected across said first and second capacitors.
Claim 4
Dependent Claim
25 words
A time delay device as recited in claim 2 further including at least one diode connected between said resistor and said second negatively charged capacitor.
References Cited (Backward Citations)
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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) | 1977-01-21 | 1977-07-23 | 1978-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-21 | 1981-07-23 | 1982-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-21 | 1985-07-23 | 1986-01-22 | $7700.00 | Window Closed / Lapsed |