Blog 4 Week 4 Assignment:
Choose 5 terms to describe from page 176 "Key Terms".
1) Form factor refers to the size of the motherboard. The motherboard, the power supply and the computer case must all match. The motherboard has posts that must fit into holes in the case. Both the case and the motherboard have holes that must line up to secure the motherboard. The power supply has to have the correct connectors in order to connect to the motherboard. There are four main form factors, ATX, MicroATX, BTX, and NLX. The ATX is the most popular and comes in three sizes, ATX, miniATX, and flexATX. The MicroATX is a low end board that only has one expansion slot and uses less power. The BTX is the newest form factor and it supports serial ATA, USB 2.0, and PCI Express slots. It has improved air flow and fans, and it does a better job of reducing heat inside the case. The NLX has a smaller motherboard that has a slot on the side that holds a daughter board, or riser card. The daughter board has the expansion slots and connections for the floppy drive and the hard drive. Another type of motherboard with a riser is called an LPX form factor. This motherboard has the connector for the daughter board in the center. Here is a great website (http://www.formfactors.org/formfactor.asp)
2) Electro-Static Discharge, or ESD, can damage or destroy computer components. Much like the shock you receive when rubbing your feet on the carpet and touching something metal, ESD can occur when working in your computer and will cause components you touch to no longer work properly. ESD can occur without the user feeling a shock and will occur while working on the inside of the computer or handling an expansion card. Always touch the bare metal of the computer case, or the metal box of the power supply, before reaching inside to touch any component. An antistatic wristband connected to the computer case, or an antistatic desk, or an antistatic desk mat are good ways to keep your computer components safe. There are also anti-ESD gloves you can wear while working inside the case.
3) Soft switch refers to the ability of the operating system (software = soft switch) to turn off the power to the computer after the user starts the shutdown procedure. If the motherboard (available on ATX and BTX form factors) and the operating system support soft switch, a normal shut down can be achieved when a user pushes the power button on the front of the case. This same feature allows the computer to be turned on with keystrokes. The computer can also be set to "wake on LAN". Soft power is another name for soft switch.
4) Power conditioners protect against power spikes as well as regulating or "conditioning" power during a brownout. Temporary voltage reductions are called brownouts or sags, and temporary voltage surges are called spikes or swells. A surge protector or a power conditioner is essentially a voltage regulator. To find out what size power condition you need multiply the amperage of each component by 120 volts. If the monitor needs 1.9 amps, this equals 228 watts. Then add up all the watts for all the equipment you have and this will tell you how big the surge protector needs to be.
5) Transformers are very important for electrical devices; they change the ratio of current and voltage. The voltage coming into your building is 110 to 120 volts of alternating current. The computer only needs 12, 5, or 3.3 volts of direct current for its components. Therefore, the transformer has to change the AC to DC power and step the voltage from 120 volts to 12 volts. In order for the transformer to convert 120 volt AC current to 12 volts, the electricity passes through two sets of copper wire coils, with an iron core in the center. The 120 volts comes in on the primary coil. Then a second coil of larger wire reduces the voltage. If the primary and secondary coils have the same number of turns, the primary and secondary voltage will be the same. However, if the secondary coil has half as many turns as the primary coil, then the voltage in the second coil will be half that of the voltage in the primary coil. To drop from 120 volts to 12 volts, the primary coil has to have ten times more coils of wire than the secondary coil. The second half of the process is to change AC to DC. This is achieved by wrapping two (or four) diodes together. The diodes act as a rectifier, which only allows part of the AC current to get through the diodes, turning the AC current into DC current. Another piece of this process is the capacitor, which collects and stores the "excess" electricity. This stored electricity is what allows the capacitor to retain a lethal charge even after the computer is unplugged. This charge must be eliminated before working nearby. To discharge a capacitor you must provide a path between the positive and negative terminals of the capacitor. The suggested method is to use a resister with a jumper and alligator clips to connect the terminals of the capacitor. (This is only the opinion of an IT student—do not try any of this without consulting professional help)
Just an interesting P.S. for anyone who has the time to read about Legacy BIOS for Windows 95 and 2000. Microsoft has an archived article entitled "APM Theory of Operation for Windows" at this website: http://www.microsoft.com/whdc/archive/w2apm.mspx
No comments:
Post a Comment