Surge suppressor with virtual ground
First Claim
Patent Images
1. A surge suppressor adapted to be connected to first and second AC power lines and which provides overvoltage protection without the need for a separate ground conductor, the surge suppressor comprising:
- (a) an AC overvoltage protection circuit comprising at least one MOV connected between the AC power lines for protecting against voltage surges on the AC power lines;
(b) an AC power receptacle having two AC power terminals and a ground terminal and adapted to receive a three prong AC power plug, the AC power terminals for connection to the AC power lines; and
(c) a virtual ground circuit connected between the ground terminal of the AC power receptacle and the AC power lines for providing a return path to the AC power lines for voltage surges appearing at the AC power receptacle, the virtual ground circuit comprising a first MOV connected between the ground terminal of the AC power receptacle and the first AC power line and a second MOV connected between the ground terminal of the AC power receptacle and the second AC power line.
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Accused Products
Abstract
A surge suppressor which provides overvoltage protection for AC power lines, coaxial transmission lines and communication lines using a virtual ground rather than a separate ground conductor.
104 Citations
12 Claims
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1. A surge suppressor adapted to be connected to first and second AC power lines and which provides overvoltage protection without the need for a separate ground conductor, the surge suppressor comprising:
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(a) an AC overvoltage protection circuit comprising at least one MOV connected between the AC power lines for protecting against voltage surges on the AC power lines;
(b) an AC power receptacle having two AC power terminals and a ground terminal and adapted to receive a three prong AC power plug, the AC power terminals for connection to the AC power lines; and
(c) a virtual ground circuit connected between the ground terminal of the AC power receptacle and the AC power lines for providing a return path to the AC power lines for voltage surges appearing at the AC power receptacle, the virtual ground circuit comprising a first MOV connected between the ground terminal of the AC power receptacle and the first AC power line and a second MOV connected between the ground terminal of the AC power receptacle and the second AC power line. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12)
(a) a coaxial transmission line overvoltage protection circuit adapted to be connected to a coaxial transmission line having a shield and a center conductor for protecting against voltage surges appearing on the coaxial transmission line; and
(b) a communication line overvoltage protection circuit adapted to be connected to a communication line for protecting against voltage surges on the communication line.
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7. The surge suppressor of any of claims 1, 2 or 3 wherein the virtual ground circuit further includes at least one gas discharge tube connected in series with the two MOVs.
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8. The surge suppressor of claim 4 wherein the coaxial transmission line overvoltage protection circuit comprises a coaxial gas discharge tube comprising a hollow conductive housing, insulating ends adapted to seal the housing, an inert gas sealed in the housing, a center conductor extending through the housing, the center conductor having a longitudinal axis oriented in a direction parallel to the direction of signal transmission, the diameter of the center conductor being varied along at least a portion of the length of the conductor within the housing for matching the impedance of the coaxial gas discharge tube to that of the coaxial transmission line.
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9. The surge suppressor of claim 4 wherein the coaxial transmission line overvoltage protection circuit comprises an avalanche diode and an inductor connected in series.
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10. The surge suppressor of any of claims 1, 2 or 3 wherein the AC overvoltage protection circuit further comprises a gas discharge tube connected in series with the MOV.
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11. The surge suppressor of any of claims 1, 2 or 3 wherein the AC overvoltage protection circuit further comprises a thermal fuse connected in series with the MOV.
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12. The surge suppressor of any of claims 1, 2 or 3 wherein the AC overvoltage protection circuit further comprises a gas discharge tube and a thermal fuse connected in series with the MOV.
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2. A surge suppressor adapted to be connected to first and second power lines and which provides overvoltage protection without the need for a separate ground conductor, the surge suppressor comprising:
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(a) an AC power plug having at least two conductors for connection to the AC power lines;
(b) an AC overvoltage protection circuit comprising at least one MOV connected between the AC power lines for protecting against voltage surges on the AC power lines;
(c) an AC power receptacle having two AC power terminals and a ground terminal and adapted to receive a three prong AC power plug, the AC power terminals for connection to the AC power lines; and
(d) a virtual ground circuit connected between the ground terminal of the AC power receptacle and the AC power lines for providing a return path to the AC power lines for voltage surges appearing at the AC power receptacle, the virtual ground circuit comprising a first MOV connected between the ground terminal of the AC power receptacle and the first AC power line and a second MOV connected between the ground terminal of the AC power receptacle and the second AC power line. - View Dependent Claims (3)
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Specification