Contact Resistance Characteristics of Elastomeric Complex Structure Contacts for Gold and Tin Printed Circuit Board
Characteristics of conductive elastomer which is composed of silicone rubber and dispersed carbon black particles shows conductive and elastic properties in one simple material. This material has been widely applied to contacts of switches and connectors of a liquid crystal panels. However, since surface state of the contact is very soft, it is difficult to remove contaminant films of contaminated opposite side contact surface and to obtain low contact resistance owing to break the film. This study has been conducted to clear structures of the elastomer which indicates removal characteristics for contaminant films and low contact resistance. As specimens, six different types of the elastomer contacts composed by different type of dispersed such materials as carbon and metal fibers, metal mesh, and plated surfaces were used. The opposite contacts were Au and Sn plated contact surface on a printed circuit board (PCB). The elastomeric contacts contained hard materials showed lower contact resistance than only dispersed carbon particles in the elastomer matrix for both contaminated PCB contact surfaces.
Carbon Blacks for Highly Conductive Rubber
Abstract The mechanism of the conductance of the electric current through a carbon black dispersion is still a problem which has not been completely solved. Rubber is an insulator and forms a homogeneous liquid phase, while carbon black is a semi-conductor and forms a dispersible solid phase. Mixtures of these two show electrical properties ranging from a near insulator to a near semiconductor. The picture which has been generally accepted for the mechanism of conductivity in rubber-carbon black compounds is one based on through-going paths of carbon black particles. These through-going paths are formed by carbon black particles either touching or situated so close to adjoining carbon black particles that the electrons have a reasonable chance to jump across the gap. This concept implies that each carbon particle must practically touch its neighbor or else the continuous chain will be broken. The definition of “touching” is not given in this concept. The number of conducting or through-going paths will be...
Generalized Thermal J‐V Characteristic for the Electric Tunnel Effect
The thermal J‐V characteristic for a tunnel junction is derived in terms of a generalized theory. The resulting functional form of the equations is similar to that of Stratton; however, in the present formulation, the physical parameters of the junction appear explicitly, and their effect upon the thermal characteristic is readily appreciated. In Stratton's work, the physical constants appear in the integrand of integral that can be solved only numerically.The theory is applied to symmetric and asymmetric junctions. For the symmetric case, it is shown that, at a given temperature, the percentage change Ĵ in the high‐temperature thermal component of current from the low‐temperature value increases initially with increasing voltage bias up to a maximum peak, and thereafter decreases rapidly. The voltage bias at which the component of thermal current maxima occurs is equal to the interfacial barrier height and, as such, permits what is probably the most accurate method of barrier height determination. Simila...