US4005344A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Protection circuit for battery powered electronic devices
Assignee: Zenith Electronics LLC
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Filing: 1975-06-23
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Granted: 1977-01-25
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Expires: 1995-06-23
Abstract
Abstract A rechargeable battery provides a source of operating potential for an electronic circuit load. An operator controlled on-off switch connects the battery to a relay, and through the normally open relay contacts, to the electronic circuit. The relay winding is returned to ground through a capacitor. When the switch is closed the relay is momentarily energized by the current which charges the capacitor. A transistor has its collector-emitter path in parallel with the capacitor and its base coupled to the movable tap on a voltage divider connected across the load. In the absence of a low voltage condition across the load, the transistor conducts maintaining relay closure for normal circuit operation.
Inventors
- 👤 Jagjit R. Gaind
- 👤 Philip J. Nowaczyk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 08:34
CPC Classifications
H; H02; H02H; H02H11/00; H02H11/006; H02H3/00; H02H3/24; H02H7/00; H02H7/18
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
159 words
For use in a television receiver utilizing a battery source of operating voltage, susceptible to being damaged by discharge below a predetermined potential, a protection circuit comprising: a viewer operable on-off switch coupled to said battery; a relay, having a normally open switch path in series with said on-off switch on said television receiver and a control winding having first and second ends, said first end coupled to said on-off switch; a capacitor; a diode coupling said capacitor to said second end of said control winding, said capacitor being charged through said control winding and said diode, when said on-off switch is moved to its on position, to momentarily energize said relay; and a transistor having a collector electrode coupled to said second end of said control winding, an emitter electrode coupled to ground, and a base electrode coupled to said television receiver, said transistor conducting to hold said relay energized if said battery potential exceeds said predetermined potential.
Claim 2
Dependent Claim
159 words
For use in a television receiver utilizing a battery source of operating voltage, susceptible to being damaged by discharge below a predetermined potential, a protection circuit comprising: a viewer operable on-off switch coupled to said battery; a relay, having a normally open switch path in series with said on-off switch on said television receiver and a control winding having first and second ends, said first end coupled to said on-off switch; a capacitor; a diode coupling said capacitor to said second end of said control winding, said capacitor being charged through said control winding and said diode, when said on-off switch is moved to its on position, to momentarily energize said relay; and a transistor having a collector electrode coupled to said second end of said control winding, an emitter electrode coupled to ground, and a base electrode coupled to said television receiver, said transistor conducting to hold said relay energized if said battery potential exceeds said predetermined potential.
Claim 3
Dependent Claim
40 words
A protection circuit as set forth in claim 1, further including an adjustable resistor voltage divider substantially in parallel with said television receiver having a moveable contact coupled to said base electrode for adjusting the conduction threshold of said transistor.
References Cited (Backward Citations)
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US3521142A
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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) | 1980-01-25 | 1980-07-26 | 1981-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-01-25 | 1984-07-26 | 1985-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-01-25 | 1988-07-26 | 1989-01-25 | $7700.00 | Window Closed / Lapsed |