30results about How to "Little change in resistivity" patented technology

A single crystal silicon wafer for use in the production of insulated gate bipolar transistors is made of single crystal silicon grown by the Czochralski method and has a gate oxide with a film thickness of from 50 to 150 nm. The wafer has an interstitial oxygen concentration of at most 7.0×1017 atoms / cm3, a resistivity variation within the plane of the wafer of at most 5% and, letting tox (cm) be the gate oxide film thickness and S (cm2) be the electrode surface area when determining the TZDB pass ratio, a density d (cm−3) of crystal originated particles (COP) having a size at least twice the gate oxide film thickness which satisfies the formula d≦−ln(0.9) / (S·tox / 2). The wafers have an increased production yield and a small resistivity variation.

A conductive paste for a thick film circuit, a thick film circuit board employing the same and a manufacturing method thereof relate to the field of thick film circuits. One of the purposes of the invention is to provide a conductive paste for a thick film circuit, which can replace a silver paste and low cost and high security. The conductive paste comprises the following components by mass percent: 72-77 percent of copper powder, 8-10 percent of inorganic adhesive, 4-6 percent of organic adhesive, 5-12 percent of organic solvent and 1-5 percent of additive. Another purpose of the invention is to provide a thick film circuit board employing the paste and adopting toughened glass as a baseplate. The third purpose of the invention is to provide a manufacturing method of the thick film circuit board. The manufacturing method comprises the steps of preparation of the conductive paste, a encapsulating paste and the baseplate, as well as the printing, encapsulating, sintering, performance test and packaging of a circuit diagram. The thick film circuit board has favorable sintering characteristic and aesthetic appearance, and can be widely used in the manufacturing field of electronic components.

The invention belongs to the field of power systems and enterprise power supply systems, and in particular discloses a neutral point and high damping resistor. A high damping resistor is connected inseries to the neutral point and the ground of a primary side or a secondary side of a transformer, and is then grounded through a current transformer. The high damping resistor has a resistance changeno more than +-2% at high temperature, and is also provided with a current meter and a thermometer, and the like. In case of high temperature, the resistance change is small and does not exceed +-2%.If the damping range is expanded, the high damping resistor is suitable if the ratio between capacitance current IR and IC that reaches 1:6 which is much greater than 1:1. The high damping resistor can be widely applicable to capacitance current of a unit voltage class system, better and effectively protects unit voltage class systems at large, can improve continuity and reliability of power supply of most of the systems, can lower incidence rate, increases power supply reliability, and greatly reduces economic loss. The high damping resistor can effectively suppress high frequency electric arc restrike overvoltage, can resist high temperature, obviates the need for expanding the space for heat dissipation, has a small size, and can save material cost.