THE COMPUTER An Introduction

THE COMPUTER

The part of the computer that most people refer to as 'the computer' is simply an enclosure or case that holds most of the components that make up a personal computer (a 'PC'). Some people refer to the computer case as the 'hard drive'. The hard drive is a small part of the computer that's inside the computer's case. This computer has only one optical drive (a drive that uses a laser to read the data from the media -- CD, DVD and Blu-ray drives) and no floppy drive. It's extremely rare for a floppy drive to be included with a new computer. Generally a card reader is installed in the slot where the floppy drive would have been installed.

Inside the CPU of a computer

1.Power Supply2.Motherboard3.CD/DVD Drive4.Cooling Fan5.Processor6.RAM7.Sound Card8.Video Card9.Hard Disk

Drive

FRONT PANEL AND BUTTONS

Starting at the bottom and going up, you can see that there is a large round button. That's the power switch. Its used to turn the computer on and off. There are other ways to switch the computer off and I'll cover them later. Above the power button, you can see a row of ports. The four rectangular ports are USB ports. They are typically used with USB flash drives or external hard drives to transfer information onto or from the computer. Between the USB ports are the headphone and microphone jacks. These can be used for gaming headsets.

FRONT PANEL AND BUTTONS

The smaller button to the right of the right-most USB port is the reset button. The reset button should only to be used in the case of a serious crash where the computer freezes. On some machines (machine is slang for computer), the reset button is omitted. If that's the case with your machine, you can reset it by holding down the power button for ~5 seconds.

Front Panel and Buttons

1.Optical Drive2.USB Ports3.Microphone Jack4.Headphone Jack5.Reset Button

6.Power Switch

POWER LIGHTS and HARD DRIVE LIGHTS

Most computers have both 'power lights' and 'hard drive lights'. The power light (power LED) lets you know when the computer is on. If it's on constantly, the computer is operating normally. If it's blinking, it's likely that the computer has gone into either hibernation or suspend mode. The hard drive LED lights up when the hard drive is being accessed or is otherwise active. On the computer below, the lights for power and the hard drive are readily visible. On the one above, the power LED illuminates around the perimeter of the power button.

POWER LIGHTS and HARD DRIVE LIGHTS

The hard drive light isn't easy to see and is really only supposed to be seen if the hard drive is active. If you look directly below the power button, you'll see a vague outline that looks like a short cylinder or pipe. That's the hard drive indicator. In the previous photo, the markings that indicated the function of a button were on the button but that's not always true. Here, the reset button is a bit below the reset marking.

Front Panel and Buttons

1.Hard Drive Light

2.Power Light

BACK PANEL

REAR PANEL SWITCHES

At the top of this computer, you can see where the power source (from the AC mains - the household wall outlet) plugs in. It is plugged into the 'power supply'. The power supply converts the mains voltage 115VAC/230VAC to the various voltages needed by the computer. On this particular power supply, you can see 2 switches. One is the main power switch. The other is the voltage selector switch. The main power switch completely cuts power to the power supply. Switching this off is essentially the same as unplugging the cord from the power supply.

REAR PANEL SWITCHES

When the end of the switch with the '1' is depressed (as it is below), the power supply is able to power up when asked to by the motherboard. The voltage selector switch allows the power supply to operate with different mains voltages. In Europe and other areas of the world (especially Philippines), they use 230VAC (Volts Alternating Current) instead of the 115VAC in the US and Japan.

P/S2 PORTS

The two P/S2 connectors below are for the mouse and keyboard. Not all new computers have these. Many of the new keyboards and mice have USB plugs. If your mouse and keyboard don't have P/S2 connectors and you want to use these (so that you don't take up any USB ports), you have to use adapters. If you decide to use adapters, you will have to restart your computer after you move the mouse and keyboard to the P/S2 ports. You should also know that some keyboards don't work well on some computers through the adapters.

P/S2 PORTS

P/S2 PORT and ADAPTER

S/PDIF

These are digital audio connectors. The one at the top uses a standard phono connector. The one below it uses a Toslink connector. It's an optical output that uses fiber optic cable to transmit the signal to the next component. The gray piece over the port is a door that swings out of the way when you plug the cable in. On this particular motherboard, there is another S/PDIF connector inside the case, near the PCI-E slots. The internal connector is used to send the digital audio signal through the video connectorsto make the DVI output function like an HDMI output. You can use an adapter to go from DVI the HDMI.

S/PDIF

The connector on the left is covered with a protective boot. The connector on the right is not. The image at the right shows the bare end of the connector.

USB 2.0 and Powered eSATA

The top two ports below are standard USB ports. There are two more lower on the panel and there are 3 more USB headers inside the computer. They can support 6 more USB ports. The powered eSATA can be used as USB ports also but they're designed for an external SATA drive. The eSATA connection is much faster than USB 2.0 so it's favored for transferring large files. USB 2.0 is specified because there is not a USB 3.0 that's faster than USB 2.0. This motherboard doesn't support USB 3.0.

USB 2.0 and Powered eSATA

This is an eSATA cable.

USB Cable

The next two images are all USB cables/connectors. The top photo shows the most common configuration. The top connector is the USB-B connector. The bottom is the USB-A. These are commonly used on printers. The second image shows the mini USB-B and micro USB-B connectors. These are commonly used on cell phones. The 'A' connector is designed to be plugged into the computer or power source (in the case of chargers like those used to charge a cell phone from a power-port adapter in a vehicle). The 'B' connector plugs into the device (most commonly a cell phone).

USB Cables

Ethernet

The two connectors on the left are the two USB connectors that were mentioned previously. The connector on the right is the ethernet port. This is where you make the connection to your network or to the internet. The top LED indicates when there is a connection. If it's constantly off, there is no connection/link to the network (cable unplugged/not seated properly in the connector or there is a problem with the network). If it's on solid, there is a connection to the network but no data being transferred. When it's on but blinking, there is activity (data being transferred to/from the network). The bottom LED on the connector indicates the speed of the connection (LED off = 10Mb/s, LED orange =100Mb/s, LED green = 1Gb/s).

Ethernet

Ethernet Cable

This is what an ethernet cable looks like. The color isn't generally important but sometimes red cables indicate that the cable is a 'crossover' cable and may not work as a link between the computer and the network. The cable construction and the terminals are the same as regular cables but the terminals are wired differently.

Ethernet Cable

Analog Audio

These connectors are for the analog audio inputs and outputs. Each jack is capable of carrying two independent channels. The green (front), black (rear), gray (side) and half of the orange (center channel) produce full range audio. The subwoofer only produces low frequencies. The pink (microphone) supports stereo input as does the blue (preamp level audio input).

Analog Audio

Analog Audio

This is one example of the type of cable that you'll use with the analog audio inputs and outputs from the sound card.

Video

The next image shows the three video output connectors on the video graphics card. The one on the leftis the DVI connector. This connector is designed to send a digital signal to a monitor but also has connections for analog video (same as the blue VGA connector). The middle connector is a standard HDMI port. This port and the DVI port (for video cards capable of doing so) can pass digital audio with the digital video signal. The cards take the S/PDIF signal from the motherboard, either via the PCI-Econnector or via a 2-conductor cable.

Video

Video Cable

This is what a VGA cable looks like. The cables intended to connect the monitor to the computer will have this type of connector (with the pins inside) on both ends. If it's an extension cable, it will have one connector like this and one connector like the one on the video card.

Video Cable

HDMI Connector