Abstract: A tight-tolerance, low-resistance, high-power chip resistor for mounting on a circuit board in parallel and adjacent relationship to such board. There are discrete terminal plates mounted on one surface of a substrate, in spaced-apart relationship to each other but still quite close to each other. Electrical connections are made by the customer to the terminal plates, at different regions thereof, without adversely affecting the tight-tolerance relationship. The terminal plates additionally provide heat spreading from the resistance film, enhancing the power handling capability of this low-resistance, high-power chip resistor.

Abstract: A fault current fusing resistor, comprising a substrate on which there is a line of resistive film formed of metal and glass in a conductive film, which line is closely confined by containing and sealing substances to prevent venting of vapor from the line during the fusing caused by an electrical fault condition.

Abstract: A power resistor having much improved heat dissipation ability to an underlying heatsink because a step or protuberance is provided that cooperates with the mounting bolt or screw to largely nullify the effects of molding-caused camber or curvature.

Abstract: A resistor combination and method, that is formed by a substrate having a resistive film on it, and pins extruding from one edge of the substrate and connected to the film. A U-shaped cold region is provided on the substrate around at least much of the film, and is so constructed that application of common high overload voltages to the pins causes vertical fracture of the substrate. The resulting substrate pieces are held by the pins to the circuit board. In one embodiment, a synthetic resin housing is provided around the substrate.

Abstract: A low-cost heat sink-mounted power film resistor having a high power rating for its footprint size, and not incorporating any housing. The resistor is bolted or otherwise secured tightly to an external heat sink in high heat-conduction relationship, the external heat sink being contacted flatwise by a rectangular internal heat sink. The footprint size and shape of the internal heat sink correspond substantially to those of commercially-marketed power film resistors having molded synthetic resin housings. The internal heat sink is bonded in high heat-conductivity relationship to a ceramic chip having a resistive film on the side thereof remote from the heat sink. Over such resistive film is a thin environmental coating. The leads are provided and connected to spaced portions of the film, on metalization pads.

Abstract: A telephone resistor combination and method, that is formed by a ceramic substrate having a resistive film on it, and pins on one edge of the substrate and connected to the film. A U-shaped cold region is provided on the substrate around at least much of the film, and is so constructed that application of common high overload voltages to the pins causes vertical fracture of the substrate. The resulting substrate pieces are held by the pins to the circuit board.

Abstract: A balancing resistor and thermistor network for telephone circuits, and combination with an external relay, which reliably handles all three levels of adverse conditions, automatically resets under certain conditions, is physically small in size, and is strong. It is a flat ceramic substrate on both surfaces of which are screen-printed thick-film balancing resistor films. Also screen-printed on both surfaces are termination traces having portions so located that when the substrate substantially instantaneously fractures it reliably and substantially instantaneously breaks the circuits through the resistive films, the fracture occurring in response to a sudden high-voltage overload. Accordingly, there is no damage to, or melting or burning of, small wires in the telephone circuits at points near to or remote from the balancing resistor network. A thermistor film is screen-printed directly onto the substrate at a central region where there is no resistive film.

Abstract: A method of soldering leads to electrical elements, such as resistors, in which a ribbon of solder, having a coating of flux, is sandwiched between a plurality of electrical elements and a plurality of leads. Hydrogen flames then cut the ribbon at points between the electrical elements and also between the leads. The hydrogen flames are then directed at the leads to melt the solder and cause extending portions of the ribbons to be drawn towards the leads.

Abstract: The film-type electrical power resistor includes a flat ceramic chip on the upper surface of which is screen-printed a resistive film. Terminals (leads) are mechanically and electrically connected to the upper chip surface, the terminals being such that the chip may be positioned by the terminals in a predetermined position in a mold cavity during manufacture of the resistor--prior to introduction of synthetic resin. The synthetic resin forms a molded electrically insulating body that embeds the portions of the terminals that are relatively near the chip, and also embeds the upper portion of the chip, but does not embed the bottom surface of the chip. The relationships are such that the lower chip surface may be engaged flatwise with a flat region of a chassis or heatsink. Accordingly, the chip is a substrate for the film, a heatsink for the film, an insulator maintaining the film electrically insulated from the chassis, and a spacer maintaining the terminals spaced from the chassis.

Abstract: The power resistor has a metal housing and heatsink, the bottom wall of which is planar and has a bolt hole therethrough for tight securing of the resistor to a chassis. A planar film-type power resistor is mounted in the housing and encapsulated therein, being held close to the bottom wall of the housing. Heat from the film-type resistor passes through the bottom wall into the chassis, the result being that the power rating of the resistor is high. The metal housing is die-cast of a zinc alloy, at extremely low cost yet with substantially the same heat-transmission characteristic as that of conventional die-castable aluminum alloys.

Abstract: A film-type resistor having a high power rating and a relatively low manufacturing cost. The structural strength of the resistor is derived primarily from a molded body that covers both a film-coated substrate and a heatsink. The heatsink, to which the substrate is bonded in high thermal-conductivity relationship, has an exposed flat bottom surface of relatively large area.

Abstract: An apparatus and method by which a flat film-type resistor is intentionally caused to thermal-shock fracture in response to a predetermined high-voltage overload condition. A stressed spring wire is mounted on such film-type resistor and connected in circuit with it. A predetermined solder and temperature gradient are employed to hold the spring wire in bent condition until the solder melts, whereupon the spring flexes and the circuit breaks. Heatsink portions are provided in the circuit board for such resistor, and receive terminal pins thereof.

Abstract: The film-type electrical power resistor includes a flat chip of aluminum oxide, having a resistive film screen-printed onto one of its sides. Leads are bonded to that side and electrically connected to the film, the leads being such that the chip may be cantilevered by the leads in a mold cavity before introduction of synthetic resin into the cavity, and with the lower chip surface spaced above the bottom cavity wall. A molded body is molded in the cavity to fully encapsulate the chip, film, and inner ends of the leads, there being no mold cup around the molded body. The molded body is formed of high thermal-conductivity thermosetting synthetic resin. Provided through the body is a bolthole for clamping of the resistor to an external chassis or heatsink. The space between the bottom surface of the chip and the flat bottom surface of the molded body is a heat-sinking volume formed of the high thermal-conductivity resin; and the bottom surface of such volume of resin is the bottom surface of the resistor.

Abstract: A method of making a compact high-voltage, high-power, thick-film screen-printed cylindrical resistor. A V-serpentine pattern is formed and adapted to fit on a cylindrical substrate having a diameter range of about 1/10 inch to about 1/2 inch. Such pattern is caused to have adjacent sections at a small acute angle to each other. Furthermore, the pattern is caused to have gaps at the open ends of the loops that are substantially wider than the gaps at the closed ends of the loops. In addition, the pattern is caused to have a sufficient number of undulations, and sufficient gap size, to achieve a predetermined voltage rating. Thereafter, the height of the pattern is changed to achieve a voltage coefficient substantially corresponding to the desired voltage coefficient. Furthermore, the resistive film material is altered to cause it to have a different resistivity, said latter resistivity being such that the same resistance value is achieved.

Abstract: A high-voltage cylindrical film-type resistor has cup-shaped end caps that receive the ends of the cylindrical substrate, each end cap having a convexly-radiused rim that has a radius of at least 1.5 mils in a plane containing the substrate axis. In accordance with the method, the stated radius is achieved by abrading, preferably tumbling.