What Is a Main Circuit Board?

A main circuit board is the brain of an electronic device; it allows the device to calculate data to perform tasks, such as operating a computer or turning on a cell phone. Regardless of the device it is controlling, each main circuit board houses specific circuitry pathways and electronic components that are designed specifically for that item to make it functional. Most boards will have peripheral devices, like speakers or cameras, attached to their circuitry so the item can be used in multiple ways.

These boards, or PCBs, are commonly made with robotic automation; the machines follow a circuit schematic supplied from an engineer for constructing a particular electronic device. Circuit pathways are laid across the PCB's surface with a screen printing process using solder paste. Electronic components, from resistors to capacitors, are placed strategically onto the circuit pathway to form a functional device. The main circuit board must be relatively sturdy since it must withstand a special soldering reflow oven to permanently attach the components to the multiple pathways.

Many people are familiar with computer motherboards; these PCBs are a common type of main circuit board. Each motherboard has a distinct arrangement of components, as well as a specific physical shape so that it can fit securely into a desktop or laptop computer. Typically, the computer's main circuit board will have at least one main microprocessor, although many manufacturers are now using multiple processors linked to one another. This complex electronic component allows the PCB to process many different inputs at a time. For example, a user may want to download a video off of the Internet while printing a word processing document; the main circuit board provides the data calculations to keep both jobs running simultaneously without slowing the computer down.

Running peripheral devices, like printers and keyboards, is a key function of the main circuit board. Each PCB has various connection points which are usually in the shape of a plug; the user can access the plugs through strategic openings in the side of the computer, for example. These access points allow the computer's main circuit board to remain versatile over several years by using different peripheral devices.

PCBs can be extremely large or tiny, depending on the device they are controlling. Regardless of the board's size, any user access to the physical PCB should be limited; the circuit pathways can be easily damaged by rogue static electricity. If a user would like to touch or work with a main circuit board, it is good practice to ground the immediate area with static mats. This precaution will prevent any accidental damage to the expensive board.