A+ Core 1 study notes- keyboard, power supply

Memory  |  Display Adapters & Monitors   |  Floppy,CD-ROM & Hard Disk  |  CPU  |  Keyboard & Power Supply  |  Printers & Cables

Networking  |  Operating System  |  Computers  |  Motherboard  |  Security  |  Miscellaneous

5.Keyboard

Key board connectors:

Key boards come with two types of connectors. They are:

• DIN-5, DIN-5 has 5 pins and used with AT style keyboards.

• Mini DIN-6, also known as PS/2 connector, has around port with 6 pins, one of which being a square pin used for alignment.

6.Power Supply

DC voltages commonly found in a PC:

• +5, and +12 volts are the DC voltages commonly found on PCs.80386 / 486 operate at +5v

• Pentium and above operate at +3.3v

• Power supply wires - yellow=+12v, blue=-12v, red=+5v, & white=-5v

One good way of determining a bad power supply is that the fan will not rotate. Also, the computer will not boot and the LED s indicating the power and disk activity will be OFF.

ATX12V 2.0 power supply provides four different voltages: 3.3Volts, 5Volts, 12Volts and -12Volts. Previous versions of ATX12V used to provide -5V, and it has been discontinued in version 2.x.

Uninterrupted Power Supply (UPS):

An UPS is required for any critical and un-interrupted use of computers. It has the following benefits:

• Provide protection against small surges

• Filters noise from entering the computer

• Provide power to the computer during line power failure

• Give stable power to computer, even when the line power is unstable.

Note that the UPS can give un-interrupted power only for a fixed amount of time under a given load, in the absence of line voltage