Surge protector for telecommunications terminals
AssigneeNorthern Telecom Limited
InventorsDavid K. Bender, Richard R. Lathrop, Jr.
Life of this patent
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Abstract
A surge protector, particularly for protecting components in a telecommunication system, has a thin ceramic substrate on a surface of which is formed a surge protector resistor having a spiral pattern in the form of a double spiral having two parallel resistor paths in series, the width of the paths and the distance between adjacent path lengths being relatively narrow. Resistance trimming links are provided for increasing the length of a resistor path, there being substantially even distribution of surge effects under surge conditions.
Claims29
A surge protector having substantially even distribution of surge effects, including heat distribution, over the area carrying the surge, comprising:
- a ceramic substrate;
- a spiral electrically resistive pattern formed on one surface of the ceramic substrate, the pattern being in the form of a double spiral having first and second physically parallel resistor paths, joined in series, the first of the paths having path lengths located between path lengths of the second path;
- the width of the path and the distance between adjacent path lengths being relatively narrow;
- and
- trimming means located at a central portion of the double spiral for increasing the length of a resistive path, the trimming means comprising shorting links extending between the first and second physically parallel paths, the first and second paths as adjusted by the trimming means providing a path for substantially uniform heat dissipation from the central portion of the spiral path to edge portions of the substrate.
A method of protecting components in a telecommunications system and the like from voltage surges, comprising:
- placing a narrow spiral electrically resistive path, in the form of a double spiral having first and second physically parallel paths joined in series at an inner end of the double spiral on a surface of a ceramic substrate to provide substantially uniform distribution of effects, including heat distribution, under voltage surge conditions, from a central portion of the double spiral to edge portions of the substrate;
- placing said resistive path in an electrical line between a voltage source and a component to be protected.
Dependencies are inferred from the claim text.