Trimmed surge resistors
OwnerJohn P. Kosinskiinventor
Life of this patent
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Abstract
An electrical resistor having a resistance value and capable of withstanding high power surges, utilizing a thick film deposited on a substrate and trimmed with one or more cuts configured to maintain a level of current crowding while increasing the resistance value of the resistor. A surge resistor can be modified in a similar fashion.
Claims20
A method of modifying a surge resistor, said method comprising:
- providing a thick film high voltage surge resistor with an initial resistance value, said thick film trimmed with a U-cut having endpoints outside said thick film to provide a trimmed film portion on one side of said U-cut and a resistive film portion on the other side of said U-cut;
- and
- coupling a J-cut with said U-cut on said resistive film portion, said J-cut having a leg portion along and a distance apart from the leg portion of said U-cut in said resistive film portion and an endpoint outside said thick film, and a curved portion having a radial dimension like the curved portion of said U-cut, said J-cut increasing the resistance value of the resistor.
A method of maintaining a level of current crowding in a trimmed surge resistor while increasing the resistance value of the resistor, said method comprising:
- providing a high voltage surge resistor with an initial resistance value, said resistor trimmed with an initial cut having endpoints outside said resistor to provide a trimmed portion on one side of said cut and a resistive portion on the other side of said cut;
- cutting a groove within said resistive portion and along said initial cut, said groove having an endpoint outside said resistive portion;
- and
- extending said groove to said initial cut with a curved cut having a radial dimension which does not extend the groove into the current pathway of the resistor, said groove cut and extended to increase the resistance to a predetermined resistance value.
A resistor capable of withstanding high power surges, comprising:
- a resistive thick film on a substrate between a pair of electrodes;
- a U-shaped groove in said thick film dividing said thick film into a resistive portion and a trimmed portion, said U-shaped groove having endpoints outside said thick film and a radius of curvature to control current crowding;
- and
- at least one J-shaped groove in said resistive portion and coupled to said U-shaped groove, said J-shaped groove having an endpoint outside said resistive portion and a radius of curvature like the radius of curvature of said U-shaped groove, such that said J-shaped groove increases the resistance value of said resistor.
An electrical resistor component having a precise resistance value and capable of withstanding high power surges, said resistor component of the type in which a thick film is deposited on a substrate and trimmed with a U-cut dividing the thick film into a resistive portion and a trimmed portion, the improvement comprising:
- at least one J-cut providing a post-trim tolerance of about .+-.0.05 percent coupled to said U-cut, said J-cut having a leg portion along and apart from the leg portion of said U-cut and an endpoint outside said resistive portion, and a curved portion having a radial dimension like the curved portion of said U-cut.
Dependencies are inferred from the claim text.