PCB

A printed circuit board (PCB) is a board used to mechanically support and electrically connect electronic components. Conductive tracks, usually etched from copper sheets, form the circuit’s interconnections and are laminated onto or between non-conductive substrates. PCBs provide physical support for components and enable reliable electrical performance by routing signals and power between parts. They come in various forms, including single-sided, double-sided, and multi-layer boards, and in rigid, flexible, or rigid-flex configurations.

The core materials of a PCB include a non-conductive substrate and copper foils. Common substrates are FR-4 epoxy glass for rigid boards and polyimide for flexible boards. Copper thickness typically ranges from 1 ounce per square foot (about 35 micrometers) to thicker for power applications. The surface is often coated with a solder mask to insulate traces, with a silkscreen layer for labeling. Through-hole vias connect layers, while blind and buried vias are used in multi-layer designs. Finishes such as HASL, ENIG, or ENEPIG protect exposed copper and improve solderability.

Design and manufacturing involve schematic capture, circuit layout, and then fabrication steps: copper etching or milling to form traces, drilling, plating, lamination of multiple layers, and finishing processes. Quality checks include electrical testing such as in-circuit or flying-probe tests. PCB design also considers impedance control, trace width and spacing, thermal management, and manufacturability.

Common PCB types include rigid boards, flexible boards, and rigid-flex boards. They are used across industries, from consumer electronics and automotive to aerospace and medical devices. Standards and compliance, such as IPC guidelines and RoHS, guide design, manufacturing practices, and environmental considerations.