The Computer Case and Power Supply

04.55 Hasyim Asyari 0 Comments

• Whether buying a tower or desktop it is recommended that the unit conforms to the ATX standard and has at least a 250-watt power supply (300 watts is ideal).
• Purchase a case that comes with a tray that allows easy access to the internal components.
• There are three basic system unit styles: desktops, towers, and portables. Each design offers characteristics that adapt the system for different environments.

• There are two important considerations in choosing a desktop case style for a computer:
• Available desktop space
• Form factor (describes the general layout of the computer case )

• Tower cases are usually designed to sit vertically on the floor beneath a desk.
• Tower cases come in three sizes:

1. Mid towers
2. Mini towers
3. Full-size towers

• The power supply unit provides electrical power for every component inside the system unit.
• There are two basic types of power supplies:
• AT power supplies
• ATX power supplies
• The power supply produces four (five in the ATX) different levels of well-regulated DC voltage for use by the system components. These are +5V, -5V, +12V, and -12V.
• In ATX power supplies, the +3.3V level is also produced and is used by the second-generation Intel Pentium processors. The IC devices on the motherboard and adapter cards use the +5V level.
• Be able to identify the uses for each voltage level and the corresponding color-coded wire. This will allow testing of the wires using a multimeter to determine if there are problems with the power supply.
• The computer power supply produces a voltage only when it has a load. Some component must be running on the machine before a voltage can be found in the power cable connectors.