Computer Hardware Prof. Henry Martínez Miranda Computer Repair Course
PCs, like the one above, are a general purpose tool with many parts.
A typical motherboard contains areas for computer memory, CPU, AGP, PCI and more.
Motherboards tie everything in your computer together.
Current socket arrangements are often named for the number of pins in the PGA. Commonly used sockets are:
Socket 478 - for older Pentium and Celeron processors
Socket 754 - for AMD Sempron and some AMD Athlon processors
Socket 939 - for newer and faster AMD Athlon processors
Socket AM2 - for the newest AMD Athlon processors
Socket A - for older AMD Athlon processors
Anyone who already has a specific CPU in mind should select a motherboard based on that CPU.
Socket 754 ZIF
A Socket 754 motherboard
Socket 939 ZIF
A Socket 939 motherboard
The newest Intel CPU does not have a PGA. It has an LGA, also known as Socket T. LGA stands for Land Grid Array. An LGA is different from a PGA in that the pins are actually part of the socket, not the CPU.
Computer hardware, such as memory, PCI and AGP connect to the motherboard through slots.
The chipset is the "glue" that connects the microprocessor to the rest of the motherboard and therefore to the rest of the computer. On a PC, it consists of two basic parts -- the north bridge and the south bridge .
A bus is simply a circuit that connects one part of the motherboard to another. The more data a bus can handle at one time, the faster it allows information to travel.
Back Panel Connectors
Computer memory has a big effect on system performance. Pictured above is SIMM memory, or single in-line memory module, which is a type of RAM memory module.
DIMM, or dual in-line memory module, has a 64-bit path to memory chips, whereas the SIMM has only a 32-bit
(184-pin DDR DIMM RAM in the photo)
SODIMM, or small outline dual in-line memory module, is made with integrated circuits and is about half the size of DIMM modules. (200-pin DDR SODIMM RAM in the photo)
A RAM upgrade can greatly extend your computer's lifespan.
The basic input-output system BIOS is the first thing you see when you turn on your computer.
A microprocessor -- also known as a CPU or central processing unit -- is a complete computation engine that is fabricated on a single chip.
64-bit processors have entered the mainstream, such as this eight-generation Athlon processor.
A hard disk is a sealed aluminum box, which has been opened in this photo. The controller electronics are attached to one side, controlling the read/write mechanism and the motor that spins the platters.
This hard drive has three platters, also called hard disks, and six read/write heads.
The arm on a hard disk holds the read/write heads and has to be incredibly fast and precise. There is one arm per read/write head, and all of them are lined up to form one unit.
Storing the Data
Data is stored on the surface of a platter in sectors and tracks . Tracks are concentric circles, and sectors are pie-shaped wedges on a track.
The Integrated Drive Electronics interface was the most popular way to connect a hard drive to a PC.
SATA (Serial ATA) Interface
Serial ATA (SATA) hard drives have become the new standard in hard drive technology.
SATA hard drives result in less clutter and increased airflow in the computer system, because SATA cables are dramatically narrower than EIDE cables.
The Peripheral Component Interconnect (PCI) bus provides direct access to system memory for connected devices. PCI slots can be used for network, graphics and sound cards.
PCI cards use 47 pins to attach to a PCI slot. Pins are thin metal feet that allow computer chips to be attached to a circuit board.
PCI Sound Card
A sound card allows a computer to create and record real, high-quality sound.
An AGP, or accelerated graphics port, allows the operating system to designate RAM for use by the graphics card (like the one above) on the fly.
Like a motherboard, a graphics card is a printed circuit board that houses a processor and RAM.
PCI Express or PCIe eliminates the need for the AGP by accepting more data and supplying more power to video cards.
Just about any computer that you buy today comes with Universal Serial Bus connectors let you attach everything from mice to printers.
PC power supplies use switcher technology to convert the AC input to lower DC voltages. The 3.3- and 5-volts are typically used by digital circuits, while the 12-volt is used to run motors in disk drives and fans.
This PC power supply has been removed from its PC case. The small, red switch at right, above the power-cord connector, is for changing line voltages in various countries.
In this photo you can see three small transformers (yellow) in the center. To the left are two cylindrical capacitors. The large finned pieces of aluminum are heat sinks.
Laptops are different from desktops only in how the components are put together.
Because of this fundamental design difference and because of a laptop's inherent portability, components have to:
Fit into a compact space
Produce less heat than desktop components
Runs at a lower voltage and clock speed
Mounts to the motherboard without using pins
Has a sleep or slow-down mode
Laptop Heat Sink and Fan
Laptops usually have small fans, heat sinks, heat spreaders or heat pipes to help dissipate the heat from the CPU.
Laptop Heat Sink and Fan
Here you can see a heat sink and fan in a laptop, similar to the hardware in a desktop.
Laptops often use smaller memory modules to save space. Memory types used in laptops include:
Small Outline Dual Inline Memory Module (SODIMM)
Dual Data Rate Synchronous RAM (DDR SDRAM)
Single data rate Synchronous RAM (SDRAM)
Proprietary memory modules
A graphics processing unit (GPU)
Most laptops have graphics capability built into the motherboard or have smaller graphics cards with a GPU designed specifically for laptop use.
Laptop LCD Screen
A laptop displays its graphics on a liquid crystal display (LCD) screen. Most screens measure between 12 and 17 inches, and the size of the screen affects the overall size of the laptop.
LiIon batteries are the current standard for laptop computers. They are light and have long life spans. They do not suffer from the memory effect, can be charged randomly, and won't overheat if overcharged. They are also thinner than any other battery available for laptops, making them ideal for the new ultra-thin notebooks. LiIon batteries can last for anything from about 950 up to 1200 charges.