Thick film varistor and method of making the same
AssigneeAllen-Bradley Company, Inc.
InventorsAllan V. Kouchich, Robert Marshall
Life of this patent
Estimating the term…
Abstract
A thick film varistor comprises a varistor film sandwiched between a pair of electrodes, one of which is in contact with a cylindrical substrate. Alternatively, the electrodes may be positioned on the same surface of the film--either in contact with the substrate or the surface of the film opposite the substrate. The preferred method of manufacture involves applying a terminating layer to each end of the substrate, forming the varistor film and the electrodes on the substrate in the desired configuration, attaching a lead wire to each end of the substrate in electrical contact with an adjacent terminating layer, and enclosing the varistor film within a conformal coating.
Claims16
A thick film varistor, the combination comprising:
- a cylindrical substrate made of an electrically insulating material and having openings at its opposite ends and an outer longitudinal surface;
- a pair of terminating layers, one being on each end of said substrate;
- a varistor film applied to the outer longitudinal surface of said substrate between said terminating layers;
- a pair of electrodes applied to said varistor film, each being in electrical contact with one of said terminating layers;
- and
- a pair of lead wires, each being inserted into an opening of said substrate at one end of said substrate and being in electrical contact with one of said terminating layers.
A thick film varistor, the combination comprising:
- a cylindrical substrate made of an electrically insulating material and having an outer longitudinal surface;
- a pair of terminating layers, one being on each end of said substrate;
- a first electrode applied to a major portion of the outer longitudinal surface of said substrate with an end in contact with one of said terminating layers;
- a varistor film applied to a portion of the outer longitudinal surface of said substrate between said first electrode and the other of said terminating layers and which is applied to the surface of said first electrode opposite the longitudinal surface of said substrate;
- a second electrode applied to the surface of said varistor film opposite said substrate and said first electrode with an end in contact with the other of said terminating layers;
- and
- a pair of lead wires, each being attached to one end of said substrate and being in electrical contact with one of said terminating layers.
A method of making a thick film varistor, comprising the steps of:
- applying a terminating layer to each end of a cylindrical substrate made of an electrically insulating material;
- applying an electrode paste to the longitudinal surface of the substrate and in contact with one of the terminating layers and heating the paste to form a first electrode;
- applying a varistor paste to the longitudinal surface of the substrate and to the first electrode;
- applying an electrode paste to the varistor paste and in contact with the other of the terminating layers and heating the varistor paste and the electrode paste to form a varistor film and a second electrode;
- and
- attaching a lead wire to each end of the substrate and in electrical contact with one of the terminating layers.
Dependencies are inferred from the claim text.