US3728702A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature alarm utilizing paired positive and negative coefficient thermistors
Assignee: Panasonic Holdings Corp
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Filing: 1970-12-07
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Granted: 1973-04-17
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Expires: 1990-12-07
Abstract
Abstract An engine temperature warning device which detects the temperature of an engine by means of a thermosensitive element comprising the combination of a negative characteristic thermistor and a positive characteristic thermistor which are thermosensitive semiconductor resistors to operate a contactless electronic solid state switching circuit to energize and deenergize a warning lamp.
Inventors
- 👤 M Miyamoto
- 👤 M Takaichi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:52
CPC Classifications
G; G01; G01K; G01K3/00; G01K3/005
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
170 words
An engine temperature warning device comprising a temperature detector including a pair of thermistors of positive and negative characteristics, a switching circuit consisting of a Schmitt circuit including a pair of transistors, the base of the first transistor of said Schmitt circuit being connected to a DC power source through said detector, a variable resistor connected in series with said detector across said DC power source for setting said temperature range, said base of said first transistor being connected to a junction point of said detector and said variable resistor, and another variable resistor connected between the emitters of said pair of transistors of said Schmitt circuit in series therewith for setting the hysteresis width of the energization and deenergization of said lamp, an amplifying transistor connected to the second transistor of said Schmitt circuit for amplifying a signal from said Schmitt circuit, and a warning lamp connected to said amplifying transistor, said lamp being energized by the output of said amplifying transistor at temperatures outside a predetermined temperature range.
Claim 2
Dependent Claim
170 words
An engine temperature warning device comprising a temperature detector including a pair of thermistors of positive and negative characteristics, a switching circuit consisting of a Schmitt circuit including a pair of transistors, the base of the first transistor of said Schmitt circuit being connected to a DC power source through said detector, a variable resistor connected in series with said detector across said DC power source for setting said temperature range, said base of said first transistor being connected to a junction point of said detector and said variable resistor, and another variable resistor connected between the emitters of said pair of transistors of said Schmitt circuit in series therewith for setting the hysteresis width of the energization and deenergization of said lamp, an amplifying transistor connected to the second transistor of said Schmitt circuit for amplifying a signal from said Schmitt circuit, and a warning lamp connected to said amplifying transistor, said lamp being energized by the output of said amplifying transistor at temperatures outside a predetermined temperature range.
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) | 1976-04-16 | 1976-10-16 | 1977-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-16 | 1980-10-16 | 1981-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-16 | 1984-10-16 | 1985-04-17 | $7700.00 | Window Closed / Lapsed |