Printed Circuit Boards (PCBs) are found in most electronic products.
Printed Circuit Boards (PCBs) are found in most electronic products. Most of the electronic components are physically mounted on the PCB. It generally provides the mechanical support for components and the electrical connections between them. Different PCB technologies can deliver a range of shapes, mechanical properties, thermal performance, electrical characteristics and can withstand different environmental conditions. Appropriate manufacturing techniques can be used to produce PCBs suited to varying levels of circuit complexity and density.
All PCBs have an insulating material which provides the mechanical structure , and a pattern of metal (usually copper) foil to form the interconnections and contact points for the components. There may be a single layer of metal foil on one side of the board. This is known as a single sided board and provides a cost effective solution where complexity and packing density is low. For more complex circuits, metal foil can be placed on both sides of the board with interconnects (known as vias) making electrical connections between the two sides. These are double sided boards. As complexity and packing density increase further additional layers of metal foil and insulating material can be added inside, producing a multi-layer board.
In some applications, the PCB is used to remove head from power components placed on it. The thermal performance of the board is then an important consideration. The board may have components on one side only, with a metal heatsink bonded to the other side. Sometimes a thin fibreglass board is used to increase thermal conductivity through the board. Particular layout techniques further improve heat dissipation.
Rigid fibreglass boards are usually produced by coating thin layers of fibreglass with copper. A photographic process is then used to produce a coating on the surface of the copper. This coating, called a "mask", is in the pattern of the interconnections. Acid is then used to remove the unwanted copper, leaving the required copper tracks. This process is known as etching.
The layers of the PCB are bonded together and holes drilled where connections between layers are required. A further copper plating process plates the inside surface of these holes, connecting any copper tracks through which they were drilled. Once all layers are in place with their tracks etched and the interconnecting holes have been plated, other non-plated holes, such as mounting holes, are drilled.
2 Layer PCB During CAD Layout
This board was designed by KSB Electronics