US3737725A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit overvoltage protector
Assignee: AVIAT CORP
•
Filing: 1971-11-08
•
Granted: 1973-06-05
•
Expires: 1991-11-08
Abstract
Abstract The combination of a voltage sensitive device, for example, a zener diode, in circuit with a current sensitive device, for example, a circuit breaker or a fuse, arranged so that an overvoltage condition causes the voltage sensitive device to actuate the current sensitive device. In one embodiment, the zener diode is connected to a source of reference potential and the output terminal of a circuit breaker. When the voltage at the output terminal of the circuit breaker exceeds the breakdown voltage of the zener diode, the impedance effectively approaches zero and the current flow through the diode to ground causes the circuit breaker to interrupt the circuit between a voltage source and an output circuit. In a modification of this embodiment, a warning lamp is provided across the circuit breaker so that when the breaker has been actuated, the lamp is illuminated. In still another embodiment, a conventional cylindrical fuse in a series circuit with a voltage source and an output circuit is provided with a zener diode having its cathode connected to the output terminal of the fuse and its anode connected to the ground provided, for example, by a conductive member about the envelope of the fuse. When the voltage at the output terminal of the fuse exceeds a minimal level, the diode conducts to cause the fuse to open the circuit between the voltage source and the output circuit.
Inventors
- 👤 T Donnelly
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:57
CPC Classifications
H; H02; H02H; H02H9/00; H02H9/04; H02H9/042
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
163 words
An electrical circuit for removing a circuit from a source of electrical potential at a predetermined overvoltage condition, comprising: a source of electrical potential, an output circuit for receiving said electrical potential, current sensitive means in circuit with said source and said output circuit and arranged so that the electrical potential supplied to said output circuit is interrupted when the current flow to said output circuit exceeds a predetermined level, and voltage sensitive means in circuit with said current sensitive means and said output circuit and arranged so that when the potential supplied to the output circuit exceeds a predetermined level, the voltage sensitive means breaks down to cause said current sensitive means to operate to interrupt the current flow to the output circuit and to remove said output circuit from said source, said voltage sensitive means being selected to become conductive and conductively fail when said potential exceeds said predetermined level, whereupon said voltage sensitive means will fail in a shorted mode.
Claim 2
Dependent Claim
163 words
An electrical circuit for removing a circuit from a source of electrical potential at a predetermined overvoltage condition, comprising: a source of electrical potential, an output circuit for receiving said electrical potential, current sensitive means in circuit with said source and said output circuit and arranged so that the electrical potential supplied to said output circuit is interrupted when the current flow to said output circuit exceeds a predetermined level, and voltage sensitive means in circuit with said current sensitive means and said output circuit and arranged so that when the potential supplied to the output circuit exceeds a predetermined level, the voltage sensitive means breaks down to cause said current sensitive means to operate to interrupt the current flow to the output circuit and to remove said output circuit from said source, said voltage sensitive means being selected to become conductive and conductively fail when said potential exceeds said predetermined level, whereupon said voltage sensitive means will fail in a shorted mode.
Claim 3
Dependent Claim
17 words
The circuit as set forth in claim 1 wherein said voltage sensitive means is a zener diode.
Claim 4
Dependent Claim
92 words
The circuit as set forth in claim 2 wherein said current sensitive means is a circuit breaker comprising an input terminal in circuit with said source, an output terminal in circuit with said output circuit and means for interrupting an electrical connection between said input and said output terminal when the current flow between said input and output terminal exceeds a predetermined level, and wherein said zener diode comprises a cathode in circuit with the output terminal of said circuit breaker, and an anode in circuit with a source of reference potential.
Claim 5
Dependent Claim
37 words
The circuit as set forth in claim 3 further including indicating means connected between said input terminal and said output terminal of said circuit breaker for providing a physical representation that an overvoltage condition has been sensed.
Claim 6
Dependent Claim
16 words
The circuit as set forth in claim 4 wherein said indicating means is an indicator lamp.
Claim 7
Dependent Claim
132 words
The combination of: a current sensitive device, including an input terminal and an output terminal, which is responsive to current flow through said device to achieve a first predetermined condition different from a nominal condition when said current flow exceeds a predetermined level, and a voltage sensitive device in circuit with the output terminal of the current sensitive device and a source of reference potential arranged so that when the voltage at the output terminal of the current sensitive device exceeds a predetermined level, the voltage sensitive device breaks down to cause the current sensitive device to achieve the first predetermined condition, said voltage sensitive means being selected to fail conductively when said voltage exceeds said predetermined level by a predetermined amount, whereupon said voltage sensitive means fails in a shorted mode.
Claim 8
Dependent Claim
132 words
The combination of: a current sensitive device, including an input terminal and an output terminal, which is responsive to current flow through said device to achieve a first predetermined condition different from a nominal condition when said current flow exceeds a predetermined level, and a voltage sensitive device in circuit with the output terminal of the current sensitive device and a source of reference potential arranged so that when the voltage at the output terminal of the current sensitive device exceeds a predetermined level, the voltage sensitive device breaks down to cause the current sensitive device to achieve the first predetermined condition, said voltage sensitive means being selected to fail conductively when said voltage exceeds said predetermined level by a predetermined amount, whereupon said voltage sensitive means fails in a shorted mode.
Claim 9
Dependent Claim
17 words
The combination as set forth in claim 6 wherein said voltage sensitive device is a zener diode.
Claim 10
Dependent Claim
117 words
A first voltage and current sensitive device comprising: a first terminal, a second terminal, a current sensitive member connected between said first terminal and said second terminal, and voltage sensitive means in circuit with either of said first terminal or said second terminal and a source of reference potential and arranged so that when the voltage sensed by said voltage sensitive means exceeds a predetermined level by a predetermined amount, the connection between said current sensitive member and said first terminal and said second terminal is interrupted, said voltage sensitive means being selected to fail conductively when said voltage exceeds said predetermined level by said predetermined amount, whereupon said voltage sensitive means fails in a shorted mode.
Claim 11
Dependent Claim
117 words
A first voltage and current sensitive device comprising: a first terminal, a second terminal, a current sensitive member connected between said first terminal and said second terminal, and voltage sensitive means in circuit with either of said first terminal or said second terminal and a source of reference potential and arranged so that when the voltage sensed by said voltage sensitive means exceeds a predetermined level by a predetermined amount, the connection between said current sensitive member and said first terminal and said second terminal is interrupted, said voltage sensitive means being selected to fail conductively when said voltage exceeds said predetermined level by said predetermined amount, whereupon said voltage sensitive means fails in a shorted mode.
Claim 12
Dependent Claim
17 words
The device as set forth in claim 8 wherein said voltage sensitive means is a zener diode.
Claim 13
Dependent Claim
56 words
The device as set forth in claim 9 further including a non-conductive envelope connecting said first terminal and said second terminal, and a conductive member supported by said envelope and in circuit with said source of reference potential, said zener diode being connected between said conductive member and either said first terminal or said second terminal.
Claim 14
Dependent Claim
17 words
The device as set forth in claim 10 wherein said zener diode is contained within said envelope.
References Cited (Backward Citations)
US3527985A
Cited
US3448341A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-04 | 1976-12-04 | 1977-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-04 | 1980-12-04 | 1981-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-04 | 1984-12-04 | 1985-06-05 | $7700.00 | Window Closed / Lapsed |