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Showing papers on "Contact resistance published in 1968"


Journal ArticleDOI
TL;DR: In this article, thermal isolation characteristics of low conductance interstitial materials determined, using test apparatus of axially loaded radiation shielded cylindrical column in vacuum, were determined using test data from a test set.
Abstract: Thermal isolation characteristics of low conductance interstitial materials determined, using test apparatus of axially loaded radiation shielded cylindrical column in vacuum

33 citations


Journal ArticleDOI
TL;DR: In this paper, the contact resistance of wiped-on InGa, evaporated In, and ion-plated In contacts on low-resistivity CdS single crystals both with and without an insulating surface layer have been examined.
Abstract: The contact resistance of wiped-on InGa, evaporated In, and ion-plated In contacts on low-resistivity CdS single crystals both with and without an insulating surface layer have been examined. Resistance-voltage characteristics were measured for applied voltages of 1 mV to ∼ 10 V. On etched crystals (without insulating layer) low-resistance ohmic contacts ( 2 ) are obtained with InGa and evaporated In, whereas the ion-plated In contacts are ohmic but have apparent resistivities of ∼ 3.6 Ω-cm 2 . On unetched crystals (with insulating layer) contacts of InGa and evaporated In are highly resistive (2 × 10 2 to 2 × 10 6 Ω-cm 2 ) and non-ohmic, but the ion-plated contacts have approximately the same characteristics as those applied to etched samples. It is concluded that the high-resistivity surface layer on low-resistivity CdS crystals must be removed or altered in order to make low-resistance ohmic contacts, and that constant R-V (or linear I-V) characteristics are a necessary but not a sufficient condition for neglecting contact resistance in two-terminal measurements of the bulk electrical properties of CdS.

14 citations



Patent
26 Aug 1968
TL;DR: In this paper, the authors describe a thin film resistor structure for a VARIABLE resistor for a TANTALUM NITRIDE. But they do not specify the type of resistors.
Abstract: A THIN FILM RESISTOR STRUCTURE FOR A VARIABLE RESISTOR IS DESCRIBED. THE STRUCTURE EXHIBITS A LOW CONTACT RESISTANCE AND GOOD TEMPERATURE STABILITY BY EMPLOYING A MULTILAYERED CONSTRUCTION. A TANTALUM NITRIDE THIN FILM LAYER IS FORMED OVER AN INSULATOR SUBSTRATE AND IS COVERED IN TURN WITH A THIN LAYER MADE OF A LOW-RESISTANCE AND ANTI-OXIDATION MATERIAL. THE COMPOSITE MULTI-LAYERED STRUCTURE IS THEN SUBJECTED TO A HEAT TREATMENT TO DIFFUSE OR, SCATTER THE LOW-RESISTIVE AND ANTI-OXIDATION MATERIAL IN A SURFACE REGIONS OF THE TANTALUM NITRIDE. THE FINAL HEAT TREATED STRUCTURE EXHIBITS A LOW NOISE LEVEL WHEN EMPLOYED WITH A BRUSH FOR OBTAINING A VARIABLE RESISTOR. THE HEAT TREATMENT IS FURTHER EMPLOYED TO IMPART A PARTICULAR TEMPERATURE COEFFICIENT OF RESISTANCE TO THE STRUCTURE. SEVERAL EMBODIMENTS AND EXAMPLES ARE SHOWN.

9 citations


01 Aug 1968
TL;DR: In this paper, contact-resistance measurements of two OFHC copper specimens loaded and unloaded in vacuum showed that the cold-welded junctions exhibited an amount of ductility generally characteristic of the specimen material.
Abstract: True stress-strain curves, developed from contact-resistance measurements be­ tween two OFHC copper specimens loaded and unloaded in vacuum, showed that the coldwelded junctions exhibited an amount of ductility generally characteristic of the specimen material. Junction ductility was greater when the experiment was kept vibration free. Deliberate vibration introduced during the loading cycle lowered the junction ductility. The contact-resistance-against-load data also seemed to indicate that impulsive forces could increase the a rea of contact under fixed load to a point where the contact a rea might revert to an elastic condition.

7 citations


Journal ArticleDOI
TL;DR: In this paper, the electric resistance of electroless nickel contacts to p-type silicon was investigated and the observed change in contact resistance due to heat treatment was discussed in relation to the chemical transformations in the nickel-silicon-phosphorus system.
Abstract: The electric resistance of electroless nickel contacts to p‐type silicon is investigated. The contact resistance increases by a factor of 100 when the resistivity of substrate silicon increases 10 times. It is also found that the contact resistance greatly increases on increasing the heat treatment temperature except for an intermediate temperature range between 450° and 600°C. The x‐ray and chemical analyses show that the heat treatment at high temperatures causes a sharp increase in content of the nickel suicide phase accompanied by a decrease in the nickel phase. The observed change in contact resistance due to heat treatment is discussed in relation to the chemical transformations in the nickel‐silicon‐phosphorus system.

2 citations


01 Jan 1968
TL;DR: Adhesion between metal couples in vacuum environment and use of contact resistance measurements to evaluate surface contamination was studied in this paper, where the authors used a contact resistance measurement to evaluate the surface contamination.
Abstract: Adhesion between metal couples in vacuum environment and use of contact resistance measurements to evaluate surface contamination

2 citations


01 Jan 1968
TL;DR: In this article, four groups of specimens were assembled for test in the following manner: Group A - Tin plated 26 AWG wire thermally stripped at normal temperature and contact crimped; Group B - Tinplated 26AWG wire mechanically stripped and contact-crimp; Group C - Tin-plated 19-strans of 38-warped wire (19 strands of 38 AWG).
Abstract: : Four groups of specimens were assembled for test in the following manner: Group A - Tin plated 26 AWG wire thermally stripped at normal temperature and contact crimped; Group B - Tin plated 26 AWG wire mechanically stripped and contact crimped; Group C - Tin-plated 26 AWG wire thermally stripped at excessively high temperatures (jacket and insulation charred) and contact crimped; Group D - Silver-plated 26 AWG copper wire (19 strands of 38 AWG) thermally stripped at excessively high temperature and contact crimped. Group A, B, C and D contacts were all crimped with the same tool and positioner to limit variables. The silver-plated wire was added to the test because previous test data accumulated by the manufacturer showed no previous contact resistance failures with 26 AWG silver-plated wire. The results showed that all groups met the initial contact resistance requirement of 7 milliohms maximum but the Group D specimens (silver-plated wire) were the only group to meet the contact resistance requirements after 40 cycles of thermal shock. The Group D specimens had very stable contact resistance and were less than 3 milliohms throughout the test. The other groups had contact resistance values ranging from 10 milliohms to ohms.

2 citations


Journal ArticleDOI
TL;DR: In this paper, a low frequency A.C. is passed through a soil sample and the consequent voltage drop in the soil is measured potentiometrically, and the measurement is carried out at different frequencies and by extrapolating to zero, the electrical conductance of the sample is obtained.
Abstract: A method for the measurement of the electrical conductivity of unsaturated soils is presented. A low frequency A.C. is passed through a soil sample and the consequent voltage drop in the soil is measured potentiometrically. The measurement is carried out at different frequencies and by extrapolating to zero, the electrical conductance of the sample is obtained. The results were in good agreement with those obtained using the D. C. technique. Yet, in the proposed method, difficulties due to electro-osmosis and polarization are avoided and it is possible to carry out measurements over extended periods of time as there occur only negligible changes in the medium measured. The internal resistance of the differential potentiometer is not great enough; therefore, there still does exist a certain influence of contact-resistance. The proposed method enables us to make reliable and accurate measurements (relative error — 0.3%) of electrical conductivity even in relatively dry soils because the contact resistance does not interfere in this set-up.

2 citations


Book ChapterDOI
01 Jun 1968
TL;DR: Transient temperature distribution in two layer one dimensional slab with initially steady state heat transfer and suddenly changed thermal contact resistances was studied in this paper, where the temperature distribution was characterized by a two-layer one-dimensional slab.
Abstract: Transient temperature distribution in two layer one dimensional slab with initially steady state heat transfer and suddenly changed thermal contact resistances