Abstract: 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.

Abstract: 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.

Abstract: A carrier for electronic components which generate heat during their operation, such as high power semiconductors, is disclosed. The carrier includes complementary ends which are designed to permit the second end of a first carrier to abut and overlap the first end of a second carrier to conserve space when more than one carrier is mounted on a substrate containing an electronic circuit. Preferably each end of each carrier has an aperture bored therethrough to allow the carrier to be mounted to the substrate with fasteners such as screws. The apertures are located so that the aperture in the second end of a first carrier aligns with the aperture in the first end of a second carrier to permit a first and a second carrier to be fastened to the substrate with a common fastener passing through the aligned apertures. Similarly, the aperture in the second end of a second carrier is positioned to align with an aperture in the first end of another carrier.