Motherboard

 It is the most important part of the Computer(you can get it as it is named as "Mother"). Coming for the dimensions of the Motherboard as a form factor ATX(Advanced Technology Extended) is the most used one. Here are the components which are connected to the motherboard.

Mouse and Keyboard:

In the starting stages of the computing days, I/O devices are connected using PS/2 connectors. But now they have been changed to USB.

USB(Universal Serial Bus):

As mentioned above I/O devices can be connected using the USB. In the starting days, any input device has to be connected using PS/2 only when the system is shutdown. This has changed with USB. With USB C everything thing can be connected to the system without switching it off.

Parallel Port:

Most printers use a special connector called a parallel port. Parallel port carries data on more than one wire, as opposed to the serial port, which uses only one wire. The parallel port uses a 25-pin female DB connector. Parallel ports are directly supported by the motherboard through a direct connection or through a dangle.

CPU Chip:

The central processing unit, also called the microprocessor performs all the calculations that take place inside a pc. CPUs come in a variety of shapes and sizes. Modern CPUs generate a lot of heat and thus require a cooling fan or heat sink. the cooling device(such as a cooling fan) is removable, although some CPU manufacturers sell the CPU with a fan permanently attached.

Ram Slots:

Random-Access Memory(RAM) stores programs and data currently being used by the CPU. RAM is measured in units called bytes. RAM has been packaged in many different ways. The most current package is called a 168-pin DIMM(Dual Inline Memory module).

IDE(Integrated Drive Electronics) Controller:

Industry standards define two common types of hard drives: EIDE(Enhanced IDE) and SCSI (Small Computer System Interface). The majority of the PCs use EIDE drives. SCSI drives show up in high-end PCs such as network servers or graphical workstations. The EIDE drive connects to the hard drive via a 2-inch wide, 40-pin ribbon cable, which in turn connects to the motherboard. IDE controller is responsible for controlling the hard drive.

PCI(Peripheral Component Interconnect) slot:

Intel introduced the Peripheral component interconnect bus protocol. The PCI bus is used to connect I/O devices(such as NIC(Network Interface Controller) or RAID(Redundant Array of Inexpensive Disks) to the main logic of the computer. The PCI bus has replaced the ISA bus.

ISA slot:

  (Industry Standard Architecture) It is the standard architecture of the Expansion bus. The motherboard may contain some slots to connect ISA compatible cards.

CMOS Battery:

 To provide CMOS with power when the computer is turned off all motherboards come with a battery. These batteries mount on the motherboard in one of three ways: the obsolete external battery, the most common onboard battery, and built-in battery.

AGP slot:

If you have a modern motherboard, you will almost certainly notice a single connector that looks like a PCI slot but is slightly shorter and usually brown. You also probably have a video card inserted into this slot. This is an Advanced Graphics Port (AGP) slot.