Vishay Intertechnology, Inc.

Vishay Dale Electronics, Inc.

Vishay Israel Ltd.

Other

Vishay International, Ltd.

Joseph Szwarc

Joel James Smejkal

Reuven Goldstein

Felix Zandman

Dany Mazliah

Toru Okamoto

Makio Sato

Jean-Michel Lanot

Ilya Aronson

On the track of a potentiometer a resistive path of thin film is deposited or a foil is bonded to a matched substrate and a parallel path is formed of discrete contact straps extending from the resistive path. The resistive path has a protecting coating and the wiper is moving on abrasion resistant contact straps. This design enables application of high precision and stability resistor technologies in the production of variable resistors destined for long service life. It enables also, in high precision applications, by maintaining the linearity of the output versus input function, a two-wire connection to the variable resistor used as a position sensor.

Precision variable resistor

A chip resistor having first and second opposite ends includes a rigid insulated substrate having a top surface and an opposite bottom surface, a first electrically conductive termination pad and a second electrically conductive termination pad, both termination pads on the top surface of the rigid insulated substrate, a layer of resistive material between the first and second electrically conductive termination pads, and a first and a second flexible lead, each made of an electrically conductive metal with a solder enhancing coating. The first flexible lead attached and electrically connected to the first electrically conductive termination pad and the second flexible lead attached and electrically connected to the second electrically conductive termination pad. Each of the flexible leads has a plurality of lead sections facilitating bending around the end of the chip resistor.

Surface mounted chip resistor with flexible leads

A high precision power resistor having the improved property of reduced resistance change due to power is disclosed. The resistor includes a substrate having first and second flat surfaces and having a shape and a composition; a resistive foil having a low TCR of about 0.1 to about 1 ppm/&#xb0; C. and a thickness of about 0.03 mils to about 0.7 mils cemented to one of the flat surfaces with a cement, the resistive foil having a pattern to produce a desired resistance value, the substrate having a modulus of elasticity of about 10&#xd7;10psi to about 100&#xd7;10psi and a thickness of about 0.5 mils to about 200 mils, the resistive foil, pattern, type and thickness of cement, and substrate being selected to provide a cumulative effect of reduction of resistance change due to power. The present invention also provides for a method of producing a high precision power resistor.

Method of manufacturing a resistor

An electrical resistor has a surface mounted four terminal current sensor of a very low resistance value and capable of handling short pulses of high power. It comprises a flat metal late, 1 to 50 mils thick, of an alloy of high electrical resistivity, to which are welded, on two opposite sides, two flat metal plates of very high electrical conductivity which serve as terminations for electrical interconnection. A slot is cut, from the outside edge toward the center, into each of the two termination plates which divides them into a wide pad for connection of current carrying wires and a narrow one for voltage sensing. The depth of the slots is optimized to get the best stability of resistance readings with changing ambient temperature and under influence of the self-heating effect.

Surface mounted four terminal resistor

A high precision power resistor having the improved property of reduced resistance change due to power is disclosed. The resistor includes a substrate having first and second flat surfaces and having a shape and a composition; a resistive foil having a low TCR of about 0.1 to about 1 ppm/&#xb0; C. and a thickness of about 0.03 mils to about 0.7 mils cemented to one of the flat surfaces with a cement, the resistive foil having a pattern to produce a desired resistance value, the substrate having a modulus of elasticity of about 10&#xd7;10psi to about 100&#xd7;10psi and a thickness of about 0.5 mils to about 200 mils, the resistive foil, pattern, type and thickness of cement, and substrate being selected to provide a cumulative effect of reduction of resistance change due to power.

High precision power resistors

A precision surface mounted foil resistor has a substrate having top and bottom planar surfaces. A resistance foil is secured to the bottom surface of the substrate and extends over the bottom. A bending protector plate of non-conductive material is superimposed over the resistance foil. A solder material is located at two areas of the foil to provide electrical contact with the PCB. The bending protector element is thicker than the solder contact areas and is provided between the solder material.

Surface mounted resistor

A monolithic resistor is provided with a central resistive metallic foil strip positioned between and attached to a pair of wings formed from an electrically conductive metallic foil. The wings include large surface areas to dissipate heat. A plurality of terminal pins are formed in the conductive strips for connection to an integrated circuit board, as well as a current source.

Monolithic heat sinking resistor

A precision resistor exhibiting a temperature coefficient of resistance which is very low and which is virtually independent of time, and capable of accepting high power, comprises a resistive foil applied to a substrate by means of an appropriate cement, wherein the coefficient of thermal expansion of the substrate is either at zero or as close to zero as is possible, and wherein the resistivity versus temperature characteristic of the foil selected is adjusted so as to compensate for the thermal strain induced change in resistance which results when the temperature of the assembly changes, and the device is reacting to the application of power virtually without creating a transient phenomenon due to the flow of heat. Also a method for producing such a precision resistor.

Precision power resistor with very low temperature coefficient of

Improved resistive electrical components are disclosed comprising an insulating or insulated substrate, a resistive foil bonded to the substrate having photoetched therein a pair of terminal pads for making electrical connections to the component and a system of resistive paths interconnecting the terminal pads, said system including an unadjustable section or sections and a plurality of adjustable sections, each having an adjustment tab associated therewith, said tab being removable to modify said section resistance and thereby altering the total resistance presented by the component between its terminal pads, the configurations of the sections differing from each other in a modified geometric progression so that the total resistance of said component is altered by a differing amount depending on which of the sections is modified by removal of its associated adjustment tab, whereby the total resistance of the component may be systematically varied in a sequence of successive steps to achieve a desired ultimate value of the total resistance of the component to the desired degree of accuracy with the least number of steps, the most effective use of substrate surface area, the least contribution to reliability degradation, and the lowest cost. Adjustment of the total resistance of the component to its desired ultimate value and precision is assisted by monitoring the component resistance while making successive adjustments. Placement of said adjustment tabs along one edge of said substrate simplifies manual adjustment and makes practical the use of automatic apparatus controlled by a monitor.

Growing community of inventors

Ramat Gan, Israel

Joseph Szwarc