Abstract:
A printed circuit board terminal includes a rectangular metal wire rod having a substantially rectangle cross-section. One longitudinal end portion of the printed circuit board terminal includes an insertion portion that is configured to be inserted into a through hole provided in a printed circuit board and soldered. A conducting metal plated layer is provided on an entire surface of the rectangular metal wire rod. One marginal portion of the insertion portion, which faces a long side direction of the rectangle cross-section, is removed to reduce a dimension in the long side direction corresponding to a width direction.
Abstract:
A chip resistor having first and second opposite ends includes a rigid insulated substrate having a top surface and an opposite bottom surface, a first electrically conductive termination pad and a second electrically conductive termination pad, both termination pads on the top surface of the rigid insulated substrate, a layer of resistive material between the first and second electrically conductive termination pads, and a first and a second flexible lead, each made of an electrically conductive metal with a solder enhancing coating. The first flexible lead attached and electrically connected to the first electrically conductive termination pad and the second flexible lead attached and electrically connected to the second electrically conductive termination pad. Each of the flexible leads has a plurality of lead sections facilitating bending around the end of the chip resistor.
Abstract:
In a vibrator support structure, a vibrator is supported on a substrate through support pins, substrate connection portions of the support pins and pin connection portions of the substrate are joined through conductive adhesive which is made of a resin including conductive filler and has a pencil hardness of about 4H or less, and the conductive adhesive has a thickness which can buffer vibrations and impacts propagated through the support pins.
Abstract:
In an electronic control unit, a chassis is provided with a plate portion, and a circuit board is secured to a board-side attaching surface of the plate portion with a predetermined space secured relative to the plate portion. The chassis is further provided with a side wall protruding from the circumferential portion of the other surface of the plate portion and is mounted on a surface of a housing incorporating a device therein, with an end surface of the side wall being seated on the surface of the housing. A bus bar is fixed at a fixing portion thereof to the board-side attaching surface between the plate portion and the circuit board and is connected to a terminal of the device which is taken out from the housing. The bus bar is provided at plural free ends thereof with branch portions at which lead portions extend to be joined at end portions thereof to the circuit board. Elastic portions for reducing stresses which are developed at juncture portions of the lead portions to the circuit board as the temperature changes are formed between the base portion and the branch portions alongside the board-side attaching surface.
Abstract:
A connector has terminals, each having a tip end portion. A wiring board has through holes. A land is provided on the wiring board about each through hole. When the connector is mounted on the wiring board, each terminal is connected to one of the lands with a part of the tip end portion being located in the corresponding through hole. The ratio of the cross-sectional area of each tip end portion to the cross-sectional area of each through hole is at least 0.11 and no more than 0.89. This improves the reliability of the joint portions between the terminals and the wiring board.
Abstract:
An apparatus and method for shielding electrical components mounted on a printed circuit board (PCB) from electromagnetic and radio frequency interference by reducing the dissipation of heat away from solder joints. In an embodiment of the invention a radio frequency (RF) shield for a printed circuit board comprises a shield for RF shielding a portion of the PCB having electronic components mounted thereon. The shield has a first portion and a second portion, wherein the first portion has a reduced cross sectional area, for reducing heat conduction between the first and the second portion when the first portion of the shield is inserted into a first plurality of holes in the PCB, for soldering the first portion of the shield to a copper foil of the PCB.
Abstract:
A device and method for mounting a surface mount package onto a printed circuit board includes inserting a pin through a printed circuit board feedthrough for providing movement of the pin within the feedthrough. One end of the pin is soldered to conductive surfaces on the bottom side of the printed circuit board while the other end of the pin id soldered to a surface mount package pad. The package is mounted in a spaced relation with a printed circuit board top surface. The pin is soldered to the board conductive surface using a high temperature solder for forming a solder joint which remains solid during subsequent soldering using a low temperature solder such as a lead tin solder type. The pin is then soldered to the pad of the surface mount package using the low temperature lead tin solder for forming a solder joint between the pad and pin. The pin is sized for loosely fitting within the feedthrough and thus movement caused by a coefficient of thermal expansion mismatch between materials of the pad, pin, and printed circuit board is absorbed by movement of the pin within the feedthrough. As a result, stress relief is provided for the solder joints.
Abstract:
A method of soldering electrical lead strands (of a width at least 0.3 inch) to a printed electrical path is disclosed. The path is planted on an alumina ceramic substrate and a solder pad is attached to a portion of the path. A flat surface portion of each lead strand is forced into full interengagement with a pad, a CO.sub.2 defocused laser beam is directed onto the soldering assembly with the beam controlled to have a beam power of at least 100 watts, a beam spot diameter no less than the width of the lead strand and no greater than the width of the pad, and a beam on-time effective to exert a controlled thermal radius on the soldering assembly to reflow only a preselected portion of the pad and effect a solder joint between the pad and strand portion, the joint having a strength of at least 400 grams. The parameters of the beam power, beam spot diameter, and beam on-time are optimally correlated by the following equation: ##EQU1## where: C is the critical thermal radius, a is the Gaussian radius at 1/e.sup.2, ln is logarithm, Tm is the melting temperature of the solder minus the specimen temperature, P is the laser beam power in watts, A is the surface absorptivity of the solder at 10.6 microns, R is the terminal resistance per unit area of the system, tc is the critical time to bring the solder to the Tm temperature, c is the heat capacity of the system.
Abstract:
The invention provides a spacer for soldering comprising an elongate body having one end provided with a tapped hole and an opposite end provided with a transverse bearing surface having a smooth centering peg projecting therefrom, the peg has a longitudinal outer passage extending over at least a fraction of its length as far as the transverse bearing surface to enable molten solder to penetrate by capillarity as far as the transverse bearing surface. The invention also provides a module including such a spacer.
Abstract:
A main body of an electronic part has multiple electrodes, to which multiple terminals are respectively connected. The terminals include a fuse terminal and a normal terminal, each of which extends from the main body to a printed board so that the main body is supported at a position above and separated from a board surface of the printed board. The fuse terminal has an intermediate portion between an electrode-connected portion and a land-connected portion. The intermediate portion has a cut-off portion having a smaller width than other portions of the fuse terminal, so that the cut-off portion is melted down when excess current flows in the fuse terminal. The intermediate portion extends in a direction parallel to the board surface or in a direction inclined to the board surface at an angle smaller than 90 degrees.