Boards

We have chosen for this category all components in which the PCB (Printed Circuit Board) forms the primary part of the structure.  Overhwelmingly (in numbers) this will be motherboards and expansion cards.  There are a few other less obvious candidates in this section as well though.  Other generic descriptions include: systemboard, logic bd and planar.  You will also be familiar with the terms PCA (Printed Circuit Assembly), PWA (Printed Wire Assembly), PWB (Printed Wiring Bd), backplane.

Motherboards are the main printed circuitry in any computer system designed to be expandable so that all other component parts can connect into it, for example:

Expansion cards, typically you plug these directly into one of a rank of slots on the mainboard. ISA (Industry Standard Architecture), parallel, AGP (Accelerated Graphics Port) and PCI (Peripheral Component Interconnect Express) are older interfaces.  More recently you are likely to see PCIe (Peripheral Component Interconnect Express) and PCI-X (Peripheral Component Interconnect eXtended).  In PCs these will comprise mainly of boards to add audio, enhanced graphics, networking capability or possibly port expansion.

In servers though, they can be for a wider range of purposes.  Riser bds are expansion cards bearing additional slots so that you can add extra memory or additional processors, backplanes for power- and drive-cages, controllers for SATA/SAS/FC/SCSI and RAID.

Smaller PCBs include various other internal components of PCs, servers and laptops. LED bds, power on/off bds, interposers for hard drives, card readers and so on.

Many other devices include multiple bds and there are usually several in peripherals such as printers for example.  The controller/engine bd, formatter bd, low and high voltage power bds, a module responsible for running the duplexer are others.