Writen by Kristy Annely

Single board computers are small circuit boards that have all the components necessary to function as a complete digital computer. We do not see them often and when we do, we have a hard time recognizing them. However, most of us must have used a single board computer in one form or another. These components are often embedded in cell phones, fax machines, GPS receivers and other electronic products that make use of computer technology.

Electronic products are not the largest market for single board computers. They find wider use in industrial applications. Such computers are called industrial single board computers, or simply industrial computers. They are used for a variety of industrial functions. Most of these computers are embedded in industrial machines that perform complex tasks, while others are arranged in a rack-mount format and are used for data acquisition and processing, as well as in product research and development.

Industrial single board computers are different than your regular home or office desktop computers. They are even quite different from other single board computers embedded in electronic products. These differences are dictated by their industrial functions. Industrial single board computers are usually designed to perform a solitary task, unlike desktop computers that are for multitasking. Because they are used in industrial processes, industrial single board computers are specifically designed to withstand various industrial factors such as shocks, vibrations, humidity, electromagnetic interference, radio frequency interference, dust, flash and mist.

Looking at the history, most industrial single board computers were initially manufactured in-house or by companies that use them. There are several reasons for this. First, industrial single board computers are often used for company-specific applications, so companies find it more practical to hire engineers to manufacture their own single board computers m rather than let another company manufacture single board computers for them.

Another reason is the lack of standards for single board computers, so the development in a particular single board computer does not necessarily affect other single board computers. Everything changed, however, when PCs began conquering the computer world. Shortly after the PC dominated the computer scene, standards for single board computers started to appear. These standards gave rise to the creation of off-the-shelf single board computers that conform to particular standards and can be programmed to perform specific tasks.

Because these single board computers cost less and are usually updated with new technologies, many companies have opted to use them rather than develop their own industrial single board computers. Some companies still opt for custom single board computers and purchase them from manufacturers rather than develop them in-house.

Writen by Stella Blue

An AC Power Adapter is an electronic device which produces a specific direct current from the mains with an Alternating Current (AC). Although actually a power supply it is popularly known as an AC Power Adapter or AC Adapter. Laptops along with most other portable devices use Direct Current (DC), this also applies to rechargeable batteries which power laptops. Direct Current has a constant flow of electric charge in one direction and flows from low to high potential. Connecting a laptop to AC is unsuitable and dangerous due to the varying magnitude and direction of the current, which can cause an internal component to fail and even result in fire.

The AC Adapter carries out the following steps to produce the correct current and voltage to power your laptop or charge your laptop battery:

• Converts the mains voltage to a lower voltage level

• Converts the AC voltage to a DC voltage by a process called rectification

• Smooths out any voltage ripple

• Converts the voltage to the required voltage to power the laptop

The other well-known name for an AC Power Adapter is battery charger or laptop battery charger. This is an important device providing you with laptop mobility and frees you of restriction from using the power cord. Check the link at the end of this article to find the correct AC Power Adapter for your laptop.

Car and Airplane Power Adapters

This is a particular design of a power adapter which accepts DC input and output DC voltage required to power a laptop. Instead of a standard plug for a wall socket, these have a specific cable that plugs in the cigarette lighter. The 12V DC supplied through the cigarette lighter socket is converted to provide a different DC voltage. This power adapter can also be used in other vehicles with similar sockets i.e. Vans, trucks and even boats. Air or airplane adapters work in the same way.

Universal Laptop Power Adapters

Complying with most mains power supplies worldwide, a universal power adapter or power supply is able to accept an input voltage ranging from 100 - 240 V with a frequency range of 50 - 60Hz. A truly universal product. However, the term universal also applies to the array of laptops it can supply power to. Laptops are built to various specifications and the power consumption varies accordingly. Physical attributes also differ between laptops and are not limited to the power socket. Manufacturers of universal laptop power adapters supply various connecting tips allowing the adapter to be connected to various laptops. These connecting tips help the power adapter detect the correct voltage to supply the laptop.

Universal power adapters are also available for cars and airplanes. Supplied with different types of plugs to fit a car cigarette lighter socket or the in-seat adapter on most airplanes, such power adapters truly allow the user to be mobile over great distances. The 2-Power Universal Car Air Power Adapter can power 98% of laptop computers.

Stella Blue

Laptop Batteries and AC Power Adapters.
universal laptop power adapters
Universal Car Air Power Adapter

Writen by Gary Hendricks

One of the most important but overlooked components in your PC is the PC case. Selecting a good PC case is an important step in building your computer, since it determines several things. It determines the number of PC components you can have, as well as how well your system’s temperature. And heck, it also determines how good your PC looks!

Let’s take a look at the different factors to consider when selecting a good PC case.

External Space

The first factor to consider is how much space your PC case is going to take up. Are you placing it on a tight, crammed desk? Or on a large desk? If you have the space, tower PC cases are a good choice. If you’re short of space, you may wish to consider smaller mini PC cases which are getting more popular these days.

Internal Space

Another factor to consider is how many components you wish to fit in your PC case. If you’re a computer nut like me, you’ll want to fit in a good motherboard, CPU, a couple of hard drives, video card, LAN card, cooling fans, a CD-ROM drive and a DVD writer. That’s a lot of components to be cramming into a PC case! Again, a good choice would be a tower PC case. However, with so many components, you have to watch out for overheating problems - make sure you deck out the system with a couple of good fans.

Motherboard Support

One thing you must absolutely remember - check that your motherboard can fit into the case! Some cases are flexible enough to support AT, ATX and Baby-AT boards, but others only support one of these sizes. Even then, you need to be careful - some cheaper ‘ATX’ cases don’t really fit ATX motherboards. I remember buying a wonderful ATX motherboard and it couldn’t fit into my PC case! Imagine my frustration!

Power Supply

Most PC cases come with power supplies. With more and more components being fitted into a PC, you will certainly need enough juice to power them. My advice is to go for at least a 400W power supply. Also make sure the unit is ATX 2.01 compliant to avoid motherboard compatibility issues.

Cooling

If you’re a overclocker or have many system components, you’ll need to ensure you’ve got enough fans in that case to cool the system. Good PC cases allow multiple (4 or more) cooling fans to be installed, ensuring good ventilation.

Looks

Just a few years back, PC cases were boring white boxes. These days, you can find a plethora of colorful PC cases - if you’re concerned about your PC’s ‘look’. Many PC enthusiasts I know go for good looking PC cases that come in a variety of colors - red, black, green, blue and what not.

Conclusion

In summary, always remember to consider the above factors when selecting PC cases. For the average home or business user, a good, simple case like the Just 4 PC case is recommended. If you’re a hardcore computer enthusiast, you’ll want to pay more attention to factors like internal space, motherboard support and cooling. Cases like the Premium 2531 and the Ultra UV Wizard would be ideal. Just consider your budget and your needs carefully - then go grab that case!

Gary Hendricks runs a hobby site on building computers. Visit his
website at http://www.build-your-own-computers.com for tips and
tricks on assembling a PC, as well as buying good computer components.

Writen by Michael Russell

Imagine a human brain without a memory component. You have all this data stored inside your head but you don’t even know how to remember it or if it’s even there. How frustrating would that be?

Computer memory or Random Access Memory (RAM) provides the facility for a PC to temporarily store programs, files and various content that is located on the hard disk. It is responsible for the data that are displayed on your screens. Everything inside your hard disk can be considered data. From programs (spreadsheet applications, word processors, messengers etc. etc.) to personal files, cookies or virus databases. This being said, the bigger the memory size capability of your PC the more programs/files you will be able to use all at the same time.

What does it look like? Memory is a circuit board loaded with RAM chips. It is around one inch wide and four inches long.

How does it work? When you click on a program, the processor calls the data from the hard disk and temporarily stores it in your RAM. You open another program and the processor puts it on top of the previous program. In short, it piles the opened programs and gets them ready for access at the command of the user. However, the number of programs that you put on top of another is dependent on the capacity of your RAM.

Consider a puzzle. You line up all the pieces of the puzzle face up all over a table and start building the puzzle section by section. You are dependent on the size of the table. If it were a 5000 piece puzzle, you’d need a very big table indeed. In the same way, the RAM allows you to open different applications or programs and gives you the benefit of being able to work on different projects at the same time provided it can accommodate the number of applications that you use, so size does matter in terms of RAM capabilities. Bigger capacity means more memory space for more applications. It’s like a human head being equipped with an elephant’s brain. Once you have reached full capacity, then this is the time that PCs begin to crash, it is like putting puzzle pieces on top of one another thereby covering your view of the one underneath. It slows you down, confuses you and generally just wastes time. So remember: the bigger the RAM that you have the more applications you will be able to work on.

Types of RAM: There are a lot of types of RAM on the market; the following list provides types that are most commonly used and most likely that you will encounter.

DRAM : Dynamic Random Access Memory

DRAM is unarguably the most common type of RAM. So as not to lose what content is inside it, it is refreshed every so often.

SRAM : Static Random Access Memory

Much faster and more efficient than DRAM but also very costly to produce.

VRAM: Video Random Access Memory

Used for video cards and on-board video memory for motherboards. Mainly provides memory for monitors.

Finally, something that you should keep in mind, RAM loses all information when it is turned off. It does not have the capacity to store the information that it gathers when it is turned on. Therefore, it is best to save often.

Writen by Cedric H. Dirose

When the first external harddrive first hit the market, it was large, clunky, slow and very expensive. Like most aspects of the world of computer technology, however, the prices of these external had drives have steadily fallen, even as the speed, reliability and storage capacity has increased so greatly. While the storage capacity of the first external hard drives was measured in mere megabytes, today most external hard drives are capable of holding hundreds of gigabytes worth of data.

There are a number of reasons why a computer owner would opt to buy an external harddrive instead of installing a secondary hard drive inside the computer case. One of the most significant benefits, of course, is that of convenience and simplicity. After all, many computer users are simply not comfortable opening the cases of their computer and installing additional hardware. When you opt for an external rather than an internal hard drive you do not need to crack the case; you simply need to plug it in and go.

Another great benefit of an external harddrive is its portability. Unlike internal hard drives, external hard drives can be moved from computer to computer in a matter of minutes, simply by unplugging them from one computer and plugging them into another. For this reason, external hard drives are often used in the business world, especially by traveling employees. Traveling employees can instantly sync up the data on an external hard drive with that on their desktop or laptop PC, and then easily transport that data anywhere in the world.

There are a number of things to consider when buying a new external hard drive, whether the drive is to be used for business or personal purposes. One consideration, of course, is that of price. While there used to be a huge price differential between internal and external hard drives, with external hard drives costing far more than internal had drives, these days the difference in price has dropped significantly, making an external harddrive a more realistic choice for more and more people.

Storage capacity, of course, is important as well. As with any type of hard drive, it is best to buy as large an external hard drive as you can afford. Even if you do not think you will ever need all those gigabytes of storage, it never hurts to have it available, and the price differential between large drives and smaller ones is generally quite low.

It is also important to look at the speed of the hard drive you are considering. The speed of the external hard drive will be expressed in RPMs, and the higher this number the faster the drive will be. In addition, you will see an average seek time number, expressed in milliseconds. The lower this number, the faster the drive should run, and this is an important consideration, especially for business users.

Writen by Michael Russell

If you’ve been brought up in the 21st century then you probably take a lot of things for granted that 30 years ago people just didn’t have. One of those things is the Internet and its ability to be able to connect people from all over the world and allow them to interact with each other in a variety of ways including sending email, visiting web sites, joining forums, attending online chats and countless other things. But none of this would be possible if it weren’t for a device that most people have never seen and probably don’t even know exist, called a router.

Routers are pieces of equipment that send messages from everyone connected to the network along thousands of different pathways. We’re going to take a behind the scenes look at exactly how these routers work.

Let’s say you’re sending an email to a friend of yours who is living across country or even in another part of the world. How does the email know to end up on your friend’s computer instead of all the other millions of computers all over the world? A good part of the work to get these messages from one computer to another is handled by routers. Rather than pass messages within networks, routers pass messages from one network to another.

To get an idea of how this works, let’s take a very simple example.

Let’s say you have two departments. Department A with 5 employees and Department B with 5 employees. Let’s say that Employee 1 from Department A wants to send an email to Employee 3 at Department B. Each department is part of its own network of computers. A router links the two networks together so that they can communicate with each other. It is the only piece of equipment that sees both networks. Many people ask, why not just make one network? The simple answer is that if the two departments do two completely different jobs for the company and send massive amounts of info within the department, you don’t want to slow down the other department with the one department’s info. To ease what they call the “traffic burden” the two departments are separated into two networks with a router put between them to connect them just in case they do want to communicate for some reason.

The way the router knows what to send where is with what is called a configuration table. These configuration table consists of info on which connections lead to which addresses, priorities for each connection, and rules for how to handle the passing of info between networks. The router then has two basic jobs. The main task is to make sure that information doesn’t go where it’s not needed so that the volume of data doesn’t clog up the network and the next task is to make sure the information goes to where it’s supposed to go.

To simplify how this happens, the router looks at the destination address of each packet sent from the source location. It checks its table to see where this address is and sends each packet to that address, bypassing all the other addresses in the network so as not to slow the network down.

In future articles we’ll take a more in depth and technical look at how packets are actually routed. Get on your thinking gear for this one.

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Michael Russell

Your Independent guide to Router

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Writen by Michael Russell

In this article we’re going to concentrate on why and how memory goes bad and what causes memory problems.

If you’ve ever worked on a PC and all of a sudden in the middle of blasting the heck out of some space invader your PC goes black and then suddenly reboots look no further than some kind of memory problem. This does not necessarily mean that the memory chip in your computer has gone bad, though that is always a possibility. But it does point to some kind of problem.

The least serious of these problems are actually caused not by the memory itself but by the applications the user happens to be running at the time. The sad truth is, some applications are just poorly written and have a tendency to overwrite memory locations outside of the area the program itself was running in. When this happens many times the memory locations overwritten just happen to be where the operating system is running and that’s what causes your computer to reboot. If you suspect that one of your programs is the culprit you can try reinstalling it and then if that doesn’t work you’ll probably have to discontinue using it and find something to replace it.

Sometimes though the problem is with the memory chip or chips themselves. Chips go bad. That is just a fact of life. But the reasons for a chip going bad can be one of many.

One of the main reasons for memory failure is the power supply of the computer. A PC uses a switching power supply to convert 120Vac to the voltages that are required by your PC. The problem with power supplies is that the voltage coming from your wall is far from perfect. If you have a defective power supply, or one that is just plain cheap, what happens is your power supply may fail to filter out the noise that can mess up your computer system. Most often this type of problem shows up as a parity error in your memory chips. So while it may appear that the chip itself is bad the real problem is with the power supply. So replacing the memory chip itself won’t do any good because the chip itself isn’t the problem.

Sometimes the problem is with the design of the motherboard. Because of the various types of SIMM motherboard manufacturers try to accommodate them all which is just not possible. By doing this they invite problems that could have been avoided by just focusing on a few SIMM and designating which SIMM will work with their board. Of course this will result in fewer sales so there is no way this is going to happen. Another problem is one that is similar to the power supply problem where the motherboard is unable to filter out enough noise and again this will cause a parity error.

Finally, chips sometimes just go bad for a number of reasons such as excessive heat, movement or even just putting the chip in wrong and breaking or bending a pin. Oddly, bad chips occur less frequently than the other problems mentioned.

So if you’re working on your PC and it goes black or you get yourself a windows memory error or blue screen of death, check your power supply and motherboard first. More likely than not you’ll find the problem in one of those two places.

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Michael Russell

Your Independent guide to Computer Memory

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Writen by Nicky Pilkington

Just a decade ago, the only people who put computers together were those individuals who possessed an extensive technical background. Advancements in technology have eliminated some of the complexities in how computers work. This change has resulted in average people who have a basic understanding of computers being able to build a system themselves. Whether you are interested in building computers to establish a new hobby or to start a business, you can so in only a few easy steps and on a shoestring budget.

The first step in building cheap computers is to determine the route you want to use to build systems. You basically have three choices when considering building cheap computers: build a system from scratch, expand on a bare bones computer, or upgrade an existing system. Building a system from scratch can be a rewarding experience. However, it is not for everyone. If you are impatient or are intimidated by mechanical tools, you are better to choose one of the other two options.

Regardless of the method you choose, you will follow three basic steps:

1. Plan

2. Assemble

3. Test

The planning phase of your project involves determining the specifications for the computer you want to build. Once you know this information you can start shopping for parts that meet those specifications. Your main considerations should be
hard-disk, memory, and CPU (central processing unit). The harddrive is important because it determines how much information you are able to store on the computer. While you could build a computer with a harddrive smaller than 2 GB (gigabytes), it is not recommended.

The harddrive and memory work together. The amount of memory you place in your computer will directly affect how the system is able to complete the different processes that you request when using the system. If you have no idea what size hard-drive and the amount of memory you need, you should consider the type of operating system you intend to load on the system. You can consult the manufacturer of your hard-drive or review the information on Cheap-Computer-Guy.com, which features a list of minimum harddrive and memory requirements for various operating systems, and use this information as a guide.

The equipment presented in this article includes the basics of a computer system. Of course, nowadays people want far more than the basics and you undoubtedly feel the same way. There are optional components available that you may want to add to your systems, which include CD or DVD drives, a modem or other communication component for Internet connectivity, or a video graphics card.

Once you have decided on the specifications of the computer you want to build, you are ready to assemble the system. In addition to detailed information about the parts you will need to build your computer, cheap-computer-guy.com includes step-by-step instructions for assembling a cheap do-it-yourself computer.

When you have finished assembling the computer, you will then need to test to make sure that the system boots and that all components are functioning properly. Once you have completed all these tests you will have built your own cheap computer.

You can find detailed information about planning, assembling and testing computers at the Cheap-Computer-Guy.com website.

Writen by Robert Thatcher

Power supply is found on every personal computer. It is device where power is received from the alternating current and converted to direct current that is useable by the computer. It is located inside the CPU distinguished by cooling fan and the power-cord receptacle.

Since the power supply receives the first surge of alternating current, it heats fast when used and cools down when the computer is shut down. The heat produced by electric surge can cause the components to overheat more frequently than other parts of the CPU. As the consequence, the power supply is the particular part that is most prone to failure.

One most common symptoms of power supply failure is the inability of power to come on. Several reasons might cause this to happen. The first thing you should do is to check whether the socket has power. To do this, all you have to do is to unplug your computer and try other plug. It can be a radio or a lamp. If the radio or the lamp work, then you have to check whether your computer plug is already busted. This might be a rare circumstance but it is probable to happen.

Another thing worth checking is the voltage setting. At the back of the CPU where the power supply is visible, you can surely locate the voltage selector. Check if it is on the right setting, which is 220v. On a 110v country, set the power supply to 110V.

If in case the power comes on but there is no live screen, you may try shutting down the computer again. Booting for at least two times would make the power supply to stabilize. Usually, this happens when the motherboard demands more timing from the current power supply.

But if you have done this for several times and there is no sign of live screen, it is more likely that the motherboard protects itself. Don’t react violently if this happens; just buy a new power supply that the motherboard suggests. It is cheaper to buy power supply than to replace the motherboard so you should be thankful your motherboard does not accept the power supply.

Another common cause of power supply failure is the fan defect. If the power supply is working properly, you should not hear any cranking sound. You must also feel a breeze from the power supply. If you hear a cranking sound, there is no need to panic. Make sure that the sound is not caused by any solid object interfering with the blades of the fan. If you notice that the power supply fan creates noisy whistle-like sound, the cause could be the capacitor.

Power supply fan can be replaced. But make sure that it is removed by technicians because if you remove it improperly, you might get electrocuted even if the power has already been removed.

In the case of PC shutting down randomly by itself, make sure that the power supply maintains its right temperature. Also check if the fan is working properly. It could also be the cause of unstable power supply. If this happens, it is advisable to replace your power supply.

These are some but most common power supply problem. If one of these happens, it is always wise to check everything first before buying a new power supply.

Robert Thatcher is a freelance publisher based in Cupertino, California. He publishes articles and reports in various ezines and provides power supply resources on http://www.your-power-supply.info

Writen by Gary Hendricks

Are you confused by the computer BIOS? The BIOS is a fundamental component of any PC and if you really want to get into the guys of a computer, it’s good through understanding what BIOS Is all about.

This article gives you a summary of what BIOS is and how you can play with the basic and advanced options in a typical BIOS configuration.

Definition

First up, let’s just define what the BIOS is. The BIOS stands for the Basic Input-Output System of a PC. It is stored on a BIOS chip on the motherboard and it is the interface between your operating system and the computer’s hardware. All the software actions you make, e.g. click a in Windows XP, are translated into machine instructions which pass through the BIOS and then subsequently to your monitor, graphics card and what not.

The BIOS is a crucial component of a PC If it fails, your PC isn’t going to boot up. I always skip a heartbeat if I see any funny behavior with a PC’s BIOS. Because it spells (almost certainly that is) doom for the computer. Make sure you’re very, very careful if you intend to fiddle around with the BIOS in anyway. Children, don’t do this at home without the supervision of a technie.

Basic Options

Let’s run through the basic options of a BIOS setup. Right after you power up the computer, there is usually a key you can hit (usually F8) which allows you to access the PC‘s BIOS.

In the basic menu in the BIOS, you should see settings for configuring hard drives and boot up options. You can specify which are your primary and secondary hard risk and which will boot up first. You can also specify if the floppy disk or CD Rom boot support before or after the hard disk.

Advanced Options

If you go in to the Advanced Options menu, you can delve into the advanced options for the BIOS configuration. If you’re into overclocking, you can specify a different CPU frequency than the default. But be very careful when you do this – you may end up burning your CPU chip if you don’t know what you’re doing.

In the advanced options menu, you can also change memory frequency and timing, as well as the AGP speed for your graphics card. Again, exercise extreme care when playing around with these settings. You can damage your PC if you don’t know what you’re doing.

There are many other options in a computer’s BIOS you can play with. Some of them include password and security options to limit access to the system, or stuff like power saving options. You can also control things like whether the Numlock key should be on or off when you first start the system.

Conclusion

I hope the article has helped you understand a little of what goes into a com0utper’s BIOS and how you can make use of it. Remember, the BIOS is such a fundamental component of any PC that you MUST exercise extreme caution when meddling with it. If you’re not sure – don’t change anything. It’s best to understand the BIOS properly from an expert or read a good book before changing it in any way.

Gary Hendricks runs a hobby site on building computers. Visit his
website at http://www.build-your-own-computers.com for tips and
tricks on assembling a PC, as well as buying good computer components.