US3579050A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High-low voltage detector
Assignee: Nortel Networks Ltd
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Filing: 1969-06-11
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Granted: 1971-05-18
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Expires: 1989-06-11
Abstract
Abstract A solid-state circuit for monitoring low and high voltage conditions in either direct current or alternating current voltage sources. A single transistor in a current control circuit is biased into or out of current conduction by two sample voltages which are related to the monitored voltage. The current flow is detected. For all values of the first sample voltage which exceed a predetermined minimum value the current control circuit will conduct current, provided also that the second sample voltage does not exceed a predetermined maximum value. Irrespective of the value of the first sample voltage, the current control circuit will cease current conduction when the second sample voltage exceeds the predetermined maximum value. The minimum and maximum sample voltage values define boundary conditions which correspond respectively to the low and high values of the monitored voltage.
Inventors
- 👤 Rabindra N Basu
- 👤 Alfred Dvorak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:25
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/165; G01R19/16533; G01R19/16538; H; H02; H02H; H02H3/00; H02H3/20; H02H3/202; H02J; H02J7/00; H02J7/90; H02J7/96
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
192 words
A high-low voltage detection circuit for monitoring a voltage from a voltage source, the circuit comprising: a pair of input terminals for connection to the voltage source; first and second resistors serially connected across the input terminals; a transistor having emitter, base and collector terminals, the emitter terminal being connected to the junction of the first and second resistors; a Zener diode coNnected between the junction of the first resistor and one of the input terminals, and the base terminal, in series opposition to the forward flow of current at the base terminal; a direct-current detection means having an input, the input having a preselected voltage thereacross; and said input being connected between the collector terminal and the junction between the second resistor and the other input terminal; the impedance of said first and second resistors and the reverse breakdown voltage of said Zener diode being selected so that the transistor will conduct only when the voltage across said Zener diode in its reverse conducting region exceeds the voltage across the first resistor and the voltage across said second resistor is less than said preselected voltage to provide a high-low voltage indication.
Claim 2
Dependent Claim
192 words
A high-low voltage detection circuit for monitoring a voltage from a voltage source, the circuit comprising: a pair of input terminals for connection to the voltage source; first and second resistors serially connected across the input terminals; a transistor having emitter, base and collector terminals, the emitter terminal being connected to the junction of the first and second resistors; a Zener diode coNnected between the junction of the first resistor and one of the input terminals, and the base terminal, in series opposition to the forward flow of current at the base terminal; a direct-current detection means having an input, the input having a preselected voltage thereacross; and said input being connected between the collector terminal and the junction between the second resistor and the other input terminal; the impedance of said first and second resistors and the reverse breakdown voltage of said Zener diode being selected so that the transistor will conduct only when the voltage across said Zener diode in its reverse conducting region exceeds the voltage across the first resistor and the voltage across said second resistor is less than said preselected voltage to provide a high-low voltage indication.
Claim 3
Dependent Claim
22 words
The high-low voltage detection circuit in claim 1, further comprising: a base current limiting resistor connected in series with the Zener diode.
Claim 4
Dependent Claim
38 words
The high-low voltage detection circuit in claims 1 or 8, further comprising: a diode connected in series with the collector terminal in such direction that the diode is in series aiding with the base-emitter junction of the transistor.
References Cited (Backward Citations)
US3139562A
Cited
US3465208A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-17 | 1974-11-16 | 1975-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-17 | 1978-11-16 | 1979-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-17 | 1982-11-16 | 1983-05-18 | $7700.00 | Window Closed / Lapsed |