Solenoid Driver and Flyback Protection A solenoid is an inductor with a mechanical load attached, and every time the driver turns it off, the stored energy has to go somewhere. The choice of where that energy goes decides how fast the valve releases, how much stress the switch sees, and…

Press-Fit Pin Insertion Force and Plated Hole Control A press-fit joint replaces solder with mechanical interference, and the whole connection depends on dimensions that are measured in tens of micrometres. The compliant pin must deform enough to grip the barrel, the plated through hole must be tight enough to hold…

Rework Practice and Heat Control on Assembled Boards Correcting a defect on an assembled board is a repair, and the difference between a repair that lasts and one that returns is the control of heat. The techniques differ, and the same technique applied without control produces damage that appears later.…

PCB Impedance Control And The TDR Test Report Once a board carries a controlled impedance line, somebody has to prove that the value was met, and on anything faster than a low speed design that proof is a measurement rather than an assurance. The tool used for the measurement is…

Solder Ball and Bump Height Control in BGA Assembly Solder ball geometry is one of the most closely watched characteristics in modern BGA assembly. Every ball has to carry the right volume, sit at the right height, and hold a narrow window from reflow through final test. When bump height…

Anisotropic Conductive Film Bonding for Flex Circuits When a flex circuit has to be joined to a rigid board, to a display, or to a glass panel, soldering is often impossible. The pitch is too fine, the substrate cannot take the temperature, or the connection has to be made over…

Load Cell Signal Conditioning and ADC Layout A load cell turns force into a very small differential voltage, typically a few millivolts at full scale, and the circuit that follows has to extract that signal from an environment full of motors, relays and switching supplies. Load cell signal conditioning is…

RF Impedance Matching: From Simulation To Measurement An RF link can look correct on paper and still disappoint on the bench. The parts are the ones the reference design used, the cables are assembled properly, and yet the gain is low, the noise is high or the waveform has developed…

Medical Impedance PCB: Tolerances, Materials And Testing Diagnostic equipment reads very small signals from a patient and turns them into an image or a waveform, and the board that carries those signals has to do it without adding distortion. That requirement drives a different set of specifications from an ordinary…

Declaration: Regulatory Requirements That Reach the PCB Every electronic product is subject to regulations that have nothing to do with whether it works, and the ones that reach the board are about materials, marking and energy. Knowing which apply early prevents a redesign at the point of certification. Restricted Substances…