1. Battery BIOS

2. CPU (Central Processing Unit) Brain of the computer Executes millions of instructions per second Built using millions of transistors Needs a heat sink and a cooling method

3. Memory Types: Volatile and Non-Volatile RAM : Random access memory ROM : Read only memory BIOS : Basic input/output system

4. Random Access Memory Volatile Accessed Randomly RAM capacity can be increased

5. Read Only Memory Non-Volatile Mainly used for chipsets ROM capacity is fixed Used for its permanence and Security Data is written once on it during fabrication

6. Basic input/output system EEPROM or Flash Performs POST (Power-on self test) Contents can be upgraded or re-installed

7. Motherboard Interfaces 1- AGP (Accelerated Graphics Port) Used for VGA (Visual Graphics Array) cards When having built-in VGA, no need for VGA card

8. Motherboard Interfaces 2- PCI (Peripheral Component Interconnect) Used for Modems, LAN cards, Sound Cards Laptops and new PCs have PCI Express

9. Battery Lithium Battery Usually 3 volts Used to Keep clock and calendar running When the PC is turned off

10. Power Supply Used to supply all components of PC with power Usually outputs 0, 3.3, 5, 12 volts Converts AC voltage from outlet To DC voltage for PC components

11. Storage 1- Fixed Storage Hard Disk - Magnetic disk - High storage capability - Non-volatile - Technologies (IDE,SCSI,ATA,SATA) Solid State Drive (SSD) - Use transistors - Faster - Non-volatile - No moving parts

12. Storage 2- Removable Storage Floppy disk -1.44MB - Not used nowadays Optical Drive - CD - DVD - Blu-Ray Flash Memory - Removable SSD - High capacities - Cheap and Fast

13. Computer Ports