A printed circuit board, often called a PCB, is a flat board that connects electronic components using thin metal pathways instead of wires. Think of it as a city map for electricity: the board is like the land, and copper traces act like roads that carry electrical signals between different parts, such as computer chips, resistors, and capacitors.

You can find PCBs inside almost every electronic device you use: phones, tablets, computers, video game consoles, and even digital watches. The board itself is usually green (though it can be other colors) and covered with tiny metal lines that look like a maze. Engineers design these pathways carefully so electricity flows exactly where it needs to go.

Before PCBs were invented in the 1940s, people had to connect electronic components with individual wires, which was slow, messy, and prone to mistakes. PCBs made it possible to manufacture complex electronics quickly and reliably. Modern PCBs can be incredibly complicated, with multiple layers stacked on top of each other, like a sandwich where each layer has its own pattern of electrical pathways.

The metal pathways are created using techniques similar to printing, where patterns are transferred onto the board using chemicals. This process allows factories to make thousands of identical boards, which is why electronics can be both powerful and affordable today.