Cooper Industries, Inc.

Charles M Newton

Paul L Urban

Lester B Postlewait

A circuit and method for measuring resistance in an active and high temperature environment is provided using a low frequency square wave as an input. The square wave input is fed through the unit under test into a full-wave rectifier and RMS circuit. The full-wave rectifier and averaging circuit cancel out errors caused by the Seebeck effect and noise. The resulting d.c. signal is proportional to the resistance of the unit under test and can be displayed.

Resistance measurement in an active and high temperature environment

A surface mount soldering/de-soldering tip holder includes a base having recesses or pockets formed therein that include at least one wall configured and sized to cooperate to a side surface of the tip. A cover plate having apertures formed therethrough is positioned on the base such that the apertures are aligned with the recesses in the base. Each aperture includes a convex portion for seating the shank of a soldering/de-soldering tip, while the portion of the cover plate adjacent to the convex portion extends over a portion of the respective recess to form a shelf. The shelf cooperates with the shoulder of a soldering/de-soldering tip once the tip is properly positioned in the recess. To remove a tip that is frictionally secured within a soldering iron adapter, the tip is inserted into one of the recesses formed in the base and positioned so that its shank is seated against the portion of the cover plate that forms the boundary for the convex portion of a respective aperture. As the soldering iron is twisted and pulled, at least one wall of the recess engages a side of the tip to prevent rotation thereof, while the shelf acts on the tip shoulder to retain the tip in the recess. To attach a tip to the adapter, the above procedure is basically reversed.

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Cheraw, SC, United States of America

Charles M Newton