Relay Control PCB: Isolation, Coil Drive and Board Cost A relay board is the simplest way to let a small logic signal control a large load, and that simplicity hides a set of design rules that decide whether the product is safe and reliable. Isolation distance, coil drive, contact protection…

Gaming Mouse PCB: Sensor, Latency and Rigid-Flex Layout A gaming mouse PCB is a small board with an unusually demanding specification. It has to report movement with almost no delay, survive being clicked millions of times, run for weeks on a charge, and do all of it inside a shell…

Metal Detector PCB: Coil Drive, Phase Detection and Noise A metal detector PCB carries an analogue instrument with a very high gain, and its design is an exercise in keeping one signal out of another. A coil is driven with a current that may be amperes, and the same coil…

Heavy Copper PCBs: Thickness, Process and Design Rules A heavy copper board is not simply a board with more copper on it. The weight of the conductor changes how the copper is etched, how the holes are drilled, how the layers are pressed and how the impedance is controlled, and…

Practical Notes on ESD Protection Electrostatic discharge is a fast, high current event that arrives through the outside world: a cable, a connector, a screw, a finger touching a metal part. The board cannot stop the event from arriving, so the design has to decide where the current goes when…

Flex PCB Coverlay and Stiffener Design: A Practical Guide A flex circuit is only as reliable as the two features that protect and support it. The coverlay seals the conductors and defines where the board may bend, while the stiffener turns a soft area into something a connector or a…

PCB Layout Essentials: Grounding, Crosstalk and Power PCB layout essentials are the small number of decisions that recur on every board, whatever the circuit does. How the ground is arranged, how much coupling is allowed between neighbours, how wide the supply conductors are and where the filter capacitors sit are…

Metal Core PCB Insulation and Thermal Path Design A metal core board is chosen when a component produces more heat than a glass reinforced laminate can move away. The copper circuit sits on a thin insulating layer, and beneath that layer is a solid aluminium or copper plate that spreads…

High Voltage Creepage and Clearance on PCB Design Spacing on a high voltage board is not a matter of taste. It is set by the distance the designer leaves between conductors, by the environment the product will live in, and by the standard the product must satisfy. Two distances matter,…

Backplane PCB Design: Passive, Active and High-Speed A backplane does almost nothing on its own, and that is the point. It carries no processing, no firmware and usually no user-facing function. Its job is to let a set of plug-in modules share power and talk to one another through a…