US4114176A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Weak camera battery warning circuit
Assignee: Pentax Corp
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Filing: 1977-08-29
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Granted: 1978-09-12
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Expires: 1997-08-29
Abstract
Abstract A weak camera battery condition is sensed by a transistor 19 whose conduction is controlled by a voltage divider 20, 21 connected across the battery 22, and in response thereto: (a) a transistor 4 is rendered conductive to continuously energize the shutter control magnet 3 which holds the shutter open, once released, and prevents any further film advance, (b) a transistor 9 is rendered conductive whereby the shutter speed display meter 8 indicates an extreme or abnormal value, and (c) a transistor 14 is rendered non-conductive whereby an LED 12 is not illuminated when a battery test switch 11 is closed.
Inventors
- 👤 Masahiro Kawasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 08:22
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/26; G03B43/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
102 words
A circuit arrangement for warning when a camera battery supply voltage falls below a predetermined threshold level, comprising: (a) circuit means for detecting when the battery voltage falls below the predetermined threshold level and for producing an output signal in response thereto, (b) a first drive circuit for rendering a shutter control magnet continuously energized in response to said output signal, (c) a second drive circuit for causing a shutter speed display element to indicate an extreme value in response to said output signal, and (d) a third drive circuit for disabling a battery test indicator in response to said output signal.
Claim 2
Dependent Claim
102 words
A circuit arrangement for warning when a camera battery supply voltage falls below a predetermined threshold level, comprising: (a) circuit means for detecting when the battery voltage falls below the predetermined threshold level and for producing an output signal in response thereto, (b) a first drive circuit for rendering a shutter control magnet continuously energized in response to said output signal, (c) a second drive circuit for causing a shutter speed display element to indicate an extreme value in response to said output signal, and (d) a third drive circuit for disabling a battery test indicator in response to said output signal.
Claim 3
Dependent Claim
34 words
A circuit arrangement as defined in claim 1, wherein the detecting circuit means comprises a voltage divider connected across the battery, and a transistor whose base terminal is connected to the voltage divider junction.
Claim 4
Dependent Claim
39 words
A circuit arrangement as defined in claim 1, wherein the first drive circuit comprises a transistor whose collector-emitter path is connected in series with the shutter control magnet and whose base terminal is connected to the detecting circuit means.
Claim 5
Dependent Claim
40 words
A circuit arrangement as defined in claim 1, wherein the second drive circuit comprises a transistor whose collector-emitter path is connected in series with the shutter speed display element and whose base terminal is connected to the detecting circuit means.
Claim 6
Dependent Claim
56 words
A circuit arrangement as defined in claim 1, wherein the third drive circuit comprises a transistor whose collector-emitter path is connected in series with the battery test indicator, and active circuit means connected between the base terminal of said transistor and the detecting circuit means for rendering said transistor non-conductive in response to said output signal.
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) | 1981-09-11 | 1982-03-13 | 1982-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-09-11 | 1986-03-13 | 1986-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-09-11 | 1990-03-13 | 1990-09-12 | $7700.00 | Window Closed / Lapsed |