US4196361A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature change detector
Assignee: Mitsubishi Electric Corp
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Filing: 1977-08-08
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Granted: 1980-04-01
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Expires: 1997-08-08
Abstract
Abstract A temperature change detector comprising a heat sensitive semiconductor switching device (heat sensitive thyristor) and which switches when a temperature of an element whose temperature is to be detected is changed by a specific value with respect to the ambient temperature. A variable impedance element such as a thermistor or a diode whose resistance is varied depending upon the ambient temperature is connected between the P gate terminal and the cathode terminal of the heat sensitive thyristor which is thermally coupled to the element whose temperature is to be detected, whereby the effect of the ambient temperature on the switching temperature characteristic of the heat sensitive thyristor is compensated.
Inventors
- 👤 Josuke Nakata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:43
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/14; G; G01; G01K; G01K3/00; G01K3/005; H03K17/94
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
219 words
A temperature change detector which comprises: a heat sensitive semiconductor switching device thermally coupled with an element whose change in temperature is to be detected and including at least one pair of main electrode terminal and a control electrode terminal, the switching device being suddenly switched from a high impedance state to a low impedance state when heated to a switching temperature T s by a change in temperature of the element whose temperature change is to be detected; and a variable impedance element connected between one of the main electrode terminals of the heat sensitive semiconductor switching device and the control electrode terminal for compensating for changes ΔT in ambient temperature of the switching device by changing the switching temperature T s of the switching device by an equal amount ΔT, the value of the impedance of the variable impedance element being varied by changes 66 T in ambient temperature of the switching device, and the value of the switching temperature T s of the switching device being controlled by the value of the impedance of the variable impedance element to change by an equal amount ΔT, whereby the temperature change of the element whose change in temperature is to be detected can be detected without maintaining constant the ambient temperature of the heat sensitive semiconductor switching device.
Claim 2
Dependent Claim
219 words
A temperature change detector which comprises: a heat sensitive semiconductor switching device thermally coupled with an element whose change in temperature is to be detected and including at least one pair of main electrode terminal and a control electrode terminal, the switching device being suddenly switched from a high impedance state to a low impedance state when heated to a switching temperature T s by a change in temperature of the element whose temperature change is to be detected; and a variable impedance element connected between one of the main electrode terminals of the heat sensitive semiconductor switching device and the control electrode terminal for compensating for changes ΔT in ambient temperature of the switching device by changing the switching temperature T s of the switching device by an equal amount ΔT, the value of the impedance of the variable impedance element being varied by changes 66 T in ambient temperature of the switching device, and the value of the switching temperature T s of the switching device being controlled by the value of the impedance of the variable impedance element to change by an equal amount ΔT, whereby the temperature change of the element whose change in temperature is to be detected can be detected without maintaining constant the ambient temperature of the heat sensitive semiconductor switching device.
Claim 3
Dependent Claim
26 words
A temperature change detector according to claim 1 wherein the heat sensitive semiconductor switching device has at least four semiconductor layers having alternatively different conductive types.
Claim 4
Dependent Claim
25 words
A temperature change detector according to claim 1 wherein the heat sensitive semiconductor switching device is formed by a PNP transistor and a NPN transistor.
Claim 5
Dependent Claim
16 words
A temperature change detector according to claim 1 wherein the variable impedance element is a thermistor.
Claim 6
Dependent Claim
17 words
A temperature change detector according to claim 1 wherein the variable impedance element is a PN diode.
References Cited (Backward Citations)
US3708720A
Cited
US3959621A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-04-01 | 1983-10-01 | 1984-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-04-01 | 1987-10-01 | 1988-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-04-01 | 1991-10-01 | 1992-04-01 | $7700.00 | Window Closed / Lapsed |