Abstract: A wireless electronic device may be provided with components such as electrical and structural components. During transmission of radio-frequency signals, antennas and wireless communications circuitry of the wireless electronic device may produce associated time-varying magnetic fields. One or more components may be covered with magnetic-resistant shield structures that protect the components from the time-varying magnetic fields by preventing magnetic-induced vibrations. The magnetic-resistant shield structures may include a conductive base layer such a layer of brass. A magnetic-resistant layer may be plated onto the conductive base layer. The magnetic-resistant layer may be formed from an amorphous nickel-phosphorous alloy. The amorphous nickel-phosphorous alloy may be produced by controlling the manufacturing temperature and proportion of phosphorous in the alloy while performing the plating operations within a length of time that ensures non-equilibrium conditions during the plating operations.

Abstract: An electronic device may be provided with integrated circuits and electrical components such as capacitors that are soldered to printed circuit boards. Liquid polymer adhesive such as encapsulant and underfill materials may be deposited on the printed circuit. Electrical components such as capacitors may be coated with the encapsulant. The underfill may be deposited adjacent to an integrated circuit, so that the underfill wicks into a gap between the integrated circuit and the printed circuit board. The encapsulant may be more viscous than the underfill and may therefore prevent the flowing underfill from reaching the electrical components. Some of the encapsulant may be located between the electrical components and the printed circuit board. The encapsulant can be cured to form an elastomeric material covering the electrical components that helps damp vibrations. The elastomeric material may be less stiff than the underfill.

Abstract: The present application describes various embodiments regarding systems and methods for providing efficient heat rejection for a lightweight and durable compact computing system having a small form factor. The compact computing system can take the form of a desktop computer. The desktop computer can include a monolithic top case having an integrated support system formed therein, the integrated support system providing structural support that distributes applied loads through the top case preventing warping and bowing. A mixed flow fan is utilized to efficiently pull cooling air through the compact computing system.

Abstract: The present application describes various embodiments regarding systems and methods for providing efficient heat rejection for a lightweight and durable compact computing system having a small form factor. The compact computing system can take the form of a desktop computer. The desktop computer can include a monolithic top case having an integrated support system formed therein, the integrated support system providing structural support that distributes applied loads through the top case preventing warping and bowing. A mixed flow fan is utilized to efficiently pull cooling air through the compact computing system.

Abstract: The described embodiments relate generally to printed circuit boards (PCBs) including a capacitor and more specifically to designs for mechanically isolating the capacitor from the PCB to reduce an acoustic noise produced when the capacitor imparts a piezoelectric force on the PCB. Conductive features can be mechanically and electrically coupled to electrodes located on two ends of the capacitor. The conductive features can be placed in corners where the amplitude of vibrations created by the piezoelectric forces is relatively small. The conductive features can then be soldered to a land pattern on the PCB to form a mechanical and electrical connection while reducing an amount of vibrational energy transferred from the capacitor to the PCB.

Abstract: A method and apparatus to improve air flow in an air circulating fan assembly by forming an inlet opening in a fan assembly. A static air pressure profile is calculated along a top portion of the fan assembly configured to operate in an enclosure. The shape of a section of the inlet opening in the top portion of the fan assembly is changed based on a pressure contour of the calculated static air pressure profile. The method is repeated iteratively one or more times using an inlet opening changed by a previously calculated static air pressure profile when calculating a subsequent static air pressure profile. The inlet opening is positioned in the top surface of the fan assembly so that the centroid of the inlet opening is laterally offset with respect to the rotational axis of an impeller in the fan assembly.

Abstract: A centrifugal blower in a cooling system of an electronic device having asymmetrical blade spacing with acceptable balance. The asymmetrical blade spacing is determined according to a set of desired acoustic artifacts that are favorable and balance that is similar to that found with equal fan blade spacing. In one embodiment, the fan impeller can include thirty one fan blades. The perceived sound quality from the fan is improved with essentially no effect on the thermal performance of the fan.

Abstract: A centrifugal blower in a cooling system of an electronic device having asymmetrical blade spacing with acceptable balance. The asymmetrical blade spacing is determined according to a set of desired acoustic artifacts that are favorable and balance that is similar to that found with equal fan blade spacing. In one embodiment, the fan impeller can include sixty one fan blades.

Abstract: A centrifugal blower in a cooling system of an electronic device having asymmetrical blade spacing with acceptable balance. The asymmetrical blade spacing is determined according to a set of desired acoustic artifacts that are favorable and balance that is similar to that found with equal fan blade spacing. In one embodiment, the fan impeller can include thirty one fan blades.

Abstract: A fan assembly for a computing device is disclosed. The device can include an impeller having a number of blades and a motor for turning the blades. The motor can turn the blades via a magnetic interaction between the impeller and the motor. A thrust bearing can be used to control a position of the impeller relative to the motor. In particular, the impeller can be configured to rotate around an axis and the thrust bearing can be used to control movement of the impeller in a direction aligned with the axis. In one embodiment, the impeller can be configured to generate aerodynamic forces, such as lift, and the parameters associated with the thrust bearing can be selected to counteract the aerodynamic forces so that the impeller remains within a desired positional range relative to the motor.

Abstract: A method and apparatus to improve air flow in an air circulating fan assembly by forming an inlet opening in a fan assembly. A static air pressure profile is calculated along a top portion of the fan assembly configured to operate in an enclosure. The shape of a section of the inlet opening in the top portion of the fan assembly is changed based on a pressure contour of the calculated static air pressure profile. The method is repeated iteratively one or more times using an inlet opening changed by a previously calculated static air pressure profile when calculating a subsequent static air pressure profile. The inlet opening is positioned in the top surface of the fan assembly so that the centroid of the inlet opening is laterally offset with respect to the rotational axis of an impeller in the fan assembly.

Abstract: A method of optimizing placement of a control source relative to a noise source includes establishing a first pool of constructive chromosomes, each constructive chromosome defining a potential spatial position for the control source in an acoustic space and each constructive chromosome including a plurality of constructive genes having a value-based value that represents an ordinate related to the potential spatial position. A second pool of constructive chromosomes is established by manipulating the value-based values of constructive genes from at least a portion of the plurality of constructive chromosomes of the first pool to create a plurality of modified constructive chromosomes, and evaluating a fitness characteristic of at least some of the constructive chromosomes from the first pool and/or at least some of the constructive chromosomes from the second pool. A portion of the constructive chromosomes are eliminated from the first and/or second pools based on the fitness characteristic.