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Malvern, PA, United States

Hernik Y.,Vishay Precision Group
Electronic Engineering Times | Year: 2010

A brief review of the advantages and disadvantages of various resistor technologies shows the interlinked effects of thermal and mechanical forces on resistor electrical characteristics is discussed. Chip resistors remain in high demand and are among the basic building blocks for many circuits. Stresses, whether mechanical or thermal, cause a resistor to change its electrical parameters. Wire wound resistors are generally classified as either 'power' or 'precision' wire wounds. The wire wound resistor is usually made by winding insulated resistance wire of a specific diameter around a bobbin. The TCR is adversely affected by the shift from the optimum film thickness. It has already been noted that wire wound resistors are not available in true chip format. Those capabilities bring high stability and reliability to system performance without any compromise among accuracy, stability and speed.

Belman M.,Vishay | Hernik Y.,Vishay Precision Group
Electronic Engineering Times | Year: 2010

Several factors influencing the generation of the noise in the resistors that depends on variables such as resistance value, temperature, applied voltage and resistor type are discussed. The resistor noise has several components but the most critical for audio applications are thermal noise and current noise. The thermal noise is independent of the resistive material and the current noise has a direct relationship to the type of resistive material. The voltage PSD of current noise is found to be directly proportional to the square of dc voltage drop U across the resistor and inversely proportional to the frequency. Resistors based on composition resistive materials such as carbon and thick film have the highest level of current noise, as a result of the significant non-homogeneity of the resistive-element materials. The noise in thin films results from occlusions, surface imperfections and non-uniform depositions effects that are more significant when the film is thinner.

Kieffer T.P.,Vishay Precision Group | Kieffer T.P.,North Carolina State University | Zhu Y.,North Carolina State University
Conference Proceedings of the Society for Experimental Mechanics Series | Year: 2014

Fe-Ni-Cr alloys have been used for more than 40 years to manufacture metal foil strain gages for specific applications. The main characteristics of this metal are high gage factor, high fatigue strength, and high thermal output. To circumvent the effect of high thermal output, typical applications in stress analysis have involved dynamic loading where the high gage factor and fatigue strength could be used to advantage and the effect of thermal output could be minimized or ignored. Typical applications in precision transducers have also involved dynamic loading and/or careful exercise of Wheatstone bridge circuit cancelation of like-thermal output in adjacent arms. In this paper, we report uniform thermal output variation in Fe-Ni-Cr metal foil strain gages. Quarter bridge and half bridge thermal output data are presented, which illustrated the suitability of this type of strain gage for stress analysis and precision transducers even when loading conditions are not dynamic. © The Society for Experimental Mechanics, Inc. 2014.


Vishay Precision Group | Date: 2014-01-16

Electric components, namely, resistors and resistor networks, low value resistors, shunt resistors, foil resistors, current sensors, potentiometers, trimmer potentiometers, capacity sensors, inductor sensors, volume control sensors, inclinometer sensors, MEMS (microelectromechanical system) sensors, vibrating wire sensors, electrical resistance strain gauges, strain gauge transducers, load cells, pressure sensors, accelerators, stress analysis systems, strain gauge instrumentations, computer software for use in weighing systems and processes control, computer software for use in stress analysis; load cell modules that include electronic instrumentation and systems used for process control, for weighing and sorting, and for process control using transducers; strain gauge instrumentation, reflection polariscopes and photoelastic plastics in the nature of strain sensitive plastics for measuring strains on surfaces of materials for optical measurement and analysis of stresses and strains; strain gauge calibration equipment; strain gauge installation testers; accessories used for surface preparation and installation of electrical resistance strain gauges and bondable resistors, namely, soldering and welding equipment, namely, portable electric powered strain gauge welding and soldering apparatus, bondable electronic terminals, electric bridge completion modules, namely, gauge installation testers, for verifying the electrical quality of strain gauge installation; digital indicators, junction boxes, digital I/O boards; force measurement, web tension and strip tension instruments and systems; pressure transmitters; electro hydraulic positioning systems; aircraft and vehicle scales and weighing equipment and systems; overload and on-board weighing equipment and systems; lift truck scales; strain indicators; data acquisition conditioners, signal conditioning amplifiers; electronic measurement and sensor equipment and systems for use in rolling mills, paper mills and mining.

Vishay Precision Group, George Kelk Corporation and GEORGE KELK Ltd | Date: 1995-08-29

digital electronic sensors for force and load measurement.

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