A Printed Circuit Board (PCB) is a flat board used to mechanically support and electrically connect electronic components using conductive pathways, tracks, or signal traces etched from copper sheets laminated onto a non-conductive substrate. PCBs are fundamental in modern electronics, serving as the backbone for circuit assembly in computers, networking devices, and other digital hardware. In cybersecurity, the integrity of PCBs is crucial, as tampering or hardware implants can introduce vulnerabilities or backdoors, potentially compromising device security. Understanding PCB design and security helps prevent hardware-based attacks and ensures the reliability of electronic systems.