Adhesion: The ability of dissimilar metals or particles to cling together as a joint is referred to as adhesion. Adhesion in the thick film is created by either a chemical (oxide bonded) or mechanical (Frit) bonds. Peel tests can be used to measure adhesion between lead and substrate and dielectric. Alpha coefficient: In a thermally sensitive resistor or Thermistor applications, the alpha (?) coefficient is a material characteristic that defines the percentage resistance change per degree centigrade. It is also known as the temperature coefficient and it's calculated by the following relationship; ? = 1/RT x dR/dT Where RT is the resistance of the component at the relevant temperature in (°C), dR/dT is the gradient of the R vs. T curve at that temperature point and alpha is expressed in (%/°C) Annealing: Annealing is a heat process whereby a material (metal or glass) is heated to a specific temperature (annealed point) and then allowed to cool slowly in order to maintain ductility and prevent crack and internal stress. Aspect Ratio (AR): The ratio of resistor length to resistor width is the aspect ratio. It's also known as the number of squares. Amplitude Balance: The maximum deviation or difference in amplitude [...]

Ensuring optimal RF performance (that is, mechanical, thermal and electrical performance) of a surface-mount technology (SMT) ceramic device requires the careful procurement and use of consistently well-behaved materials, the use of proper and rigorous design principles, and proper attention paid to the appropriate parameters (on the part of the manufacturer in its design, and on the part of the user in its operation). In this way, the reflection, dissipation, and transmission signatures of the device in question remain consistently and predictably well behaved. Some instances of devices that are designed to maximize dissipative loss are terminations, loads, absorptive filters and dividers, etc. Typically, these devices must minimize reflective loss (regardless of the nature of the signals at their inputs), which, when combined with proper dissipative design, results in an optimal transmission signature as well. SMT devices that are non-dissipative by design are hybrid couplers, power dividers, filters, etc. Filters, of course, are designed such that some signals are to experience a minimum of reflection and dissipation while maximizing transmission, whereas other signals are to experience a maximum of reflection while minimizing transmission. Other dissipative devices are attenuators, voltage dropping resistors, resistive splitters, etc. Attenuators must be designed such that reflective [...]

Considerations for proper soldering methods and techniques of chip resistors. Soldering is the process of using a metal alloy with a low melting temperature to fuse or ‘solder' the electrical contacts of a component to the pads on a circuitboard. Proper soldering enhances the strength and conductivity of the connection. Poor soldering can result in weak connections, higher resistance that causes heat buildup at the connection, and possible failure of the component. Did you also know that hermetically sealed circuit boards are useful for projects with complex computations? A hermetic seal is widely used in applications that require light and compact sealing methods such as missiles or bomb fuses. You can find more information and get a circuit board sealer here. The type of components and the pads to which they will be attached dictate the appropriate soldering method. The correct amount and duration of heat to be applied are determined by the component, the circuit board, the solder pads, the solder and flux, and the environment in which the soldering takes place. For this reason, effective soldering requires reasonable controls. Some experimentation is required to determine the optimal conditions for each specific application. General Soldering Guidelines: All soldering applications [...]

Temperature/Duration Limit Recommendations PEAK TEMPERATURE TIME 260 deg C (500 deg F) 5 Seconds 250 deg C (482 deg F) 10 Seconds 240 deg C (464 deg F) 20 Seconds 230 deg C (446 deg F) 30 Seconds 204 deg C (400 deg F) 40 Seconds Although specific applications will vary and many other variables will need to be considered such as board type, adjacent components, and delivery methods for the solder, using a standard Mil grade solder (ie. SN-62) and a good Mil grade RA or RMA flux, the profile depicted above will typically give good results. Note: Regarding Aluminum Nitride Components: ALN is very thermally conductive. Contact style soldering methods that do not consider the heat-sync properties of these high thermally conductive components (ie. Soldering irons and hot air column heating methods) can be difficult to use. Best results occur with hot plate reflow, or belt or chamber reflow methods. ALN has a TC of 170 W/ m/ °K and this high heat conductivity can cool soldering iron tips the instant they come into contact with the component which often results in turning up the heat on the iron much too high to compensate. Download our tech note [...]