US3760192A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fail-safe level detector
Assignee: Westinghouse Electric Corp
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Filing: 1972-02-18
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Granted: 1973-09-18
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Expires: 1992-02-18
Abstract
Abstract A periodic or carrier signal is provided to the anode electrode of a zener diode through a transformer. A signal means provides a direct current level to the cathode electrode of the zener diode. Whenever the direct current level provided by the signal means is at least at a predetermined signal level the zener diode conducts and provides a low impedance path for the periodic signal to the input of an amplifier. The amplifier amplifies the periodic signal and provides the latter signal to the input of a signal utilization device. Whenever the direct current level provided by the signal means is at a signal level less than the predetermined signal level the zener diode is held non-conductive and the signal path to the input of the amplifier is blocked, whereby an amplified signal is not provided to the input of the signal utilization means.
Inventors
- 👤 J Darrow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 00:47
CPC Classifications
G; G01; G01P; G01P1/00; G01P1/07; G01P1/08; G01P1/10; G01P1/103; B; B61; B61L; B61L1/00; B61L1/20; H; H03; H03K; H03K17/00; H03K17/30; H03K17/51; H03K17/74
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
235 words
A level detector comprising in combination: an amplifier having an input to which a signal to be amplified may be applied and an output at which the amplified signal is manifested; a first signal means for providing a first signal which at given times may be at different signal levels; a second signal means for providing a periodic signal; a transformer having a primary winding connected to said second signal means and also having a secondary winding; and a zener diode having an anode electrode connected to a selected one of said first signal means and the secondary winding of said transformer, and a cathode electrode connected to the remaining one of said first signal means and the secondary winding of said transformer, with the electrode that is connected to said first signal means being also connected to the input of said amplifier, said zener diode becoming conductive and providing a signal path for the application of said periodic signal to the input of said amplifier for amplification whenever said first signal is at a selected signal level independent of the signal level of said periodic signal, with said zener diode becoming non-conductive and opening said signal path for blocking the application of said periodic signal to the input of said amplifier whenever said first signal is at a level less than said selected signal level independent of the signal level of said periodic signal.
Claim 2
Dependent Claim
235 words
A level detector comprising in combination: an amplifier having an input to which a signal to be amplified may be applied and an output at which the amplified signal is manifested; a first signal means for providing a first signal which at given times may be at different signal levels; a second signal means for providing a periodic signal; a transformer having a primary winding connected to said second signal means and also having a secondary winding; and a zener diode having an anode electrode connected to a selected one of said first signal means and the secondary winding of said transformer, and a cathode electrode connected to the remaining one of said first signal means and the secondary winding of said transformer, with the electrode that is connected to said first signal means being also connected to the input of said amplifier, said zener diode becoming conductive and providing a signal path for the application of said periodic signal to the input of said amplifier for amplification whenever said first signal is at a selected signal level independent of the signal level of said periodic signal, with said zener diode becoming non-conductive and opening said signal path for blocking the application of said periodic signal to the input of said amplifier whenever said first signal is at a level less than said selected signal level independent of the signal level of said periodic signal.
Claim 3
Dependent Claim
53 words
The combination claimed in claim 1 wherein said amplifier comprises a transistor, with the emitter electrode forming one of the input and output for said amplifier, and the collector electrode forming the remaining one of the input and output for said amplifier, and the base electrode bEing connected by impedance means to ground.
Claim 4
Dependent Claim
16 words
The combination claimed in claim 2 including a detector connected to the output of said amplifier.
Claim 5
Dependent Claim
17 words
The combination claimed in claim 3 including a load of finite impedance being connected to said detector.
Claim 6
Dependent Claim
34 words
The combination claimed in claim 2 including a first biasing network connected between the electrode of said zener diode that is connected to said first signal means and the base electrode of said transistor.
Claim 7
Dependent Claim
46 words
The combination claimed in claim 5 including a second biasing network connected between the electrode of said zener diode that is connected to said first signal means and the one of the emitter and collector electrodes of said transistor which forms the input for said amplifier.
Claim 8
Dependent Claim
219 words
A level detector comprising in combination: a first signal means for providing a first signal which at given times may be at different direct current levels; a second signal means for providing a periodic signal; a transformer having a primary winding connected to said second signal means and also having a secondary winding; a zener diode having an anode electrode connected to a selected one of said first signal means and the secondary winding of said transformer, and having a cathode electrode connected to the remaining one of said first signal means and the secondary winding of said transformer; a transistor having base, emitter, and collector electrodes; a first resistor; a first capacitor connected in parallel with said first resistor and being connected between the electrode of said zener diode that is connected to said first signal means and a selected one of the emitter and collector electrodes of said transistor; a first diode having one electrode connected to the electrode of said zener diode that is connected to said first signal means; a second resistor connected at one terminal to the remaining electrode of said first diode and connected at the remaining terminal to the base electrode of said transistor; and a load device connected to the remaining one of the emitter and collector electrodes of said transistor.
Claim 9
Dependent Claim
219 words
A level detector comprising in combination: a first signal means for providing a first signal which at given times may be at different direct current levels; a second signal means for providing a periodic signal; a transformer having a primary winding connected to said second signal means and also having a secondary winding; a zener diode having an anode electrode connected to a selected one of said first signal means and the secondary winding of said transformer, and having a cathode electrode connected to the remaining one of said first signal means and the secondary winding of said transformer; a transistor having base, emitter, and collector electrodes; a first resistor; a first capacitor connected in parallel with said first resistor and being connected between the electrode of said zener diode that is connected to said first signal means and a selected one of the emitter and collector electrodes of said transistor; a first diode having one electrode connected to the electrode of said zener diode that is connected to said first signal means; a second resistor connected at one terminal to the remaining electrode of said first diode and connected at the remaining terminal to the base electrode of said transistor; and a load device connected to the remaining one of the emitter and collector electrodes of said transistor.
References Cited (Backward Citations)
US3213294A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-17 | 1977-03-19 | 1977-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-17 | 1981-03-19 | 1981-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-17 | 1985-03-19 | 1985-09-18 | $7700.00 | Window Closed / Lapsed |