Pen Drive

Sometimes referred to as a jump drive, the pen drive is a portable USB flash memory device that can be used to quickly transfer audio, video, and data files from the hard drive of one computer to another. With a construction that is small enough to fit into a pocket, the pen drive derives its name from the fact that many of these USB drive devices resemble a small pen or pencil in size and shape.

Pen drives are classified as NAND style data storage devices. Equipped with a large amount of memory capacity, the pen drive is considered to be an improvement on both the older floppy drive disks and the more modern compact disks that are often used to copy data and reload the files on a different hard drive. Even a pen drive with a relatively low storage capacity tends to provide plenty of space for a number of files. The types of files that can be loaded onto a pen drive are all the common types that can be housed on any hard drive. This makes it possible for persons to copy photos, spreadsheets, word processing documents, movie clips, music tracks, and just about any other type of file.

Utilizing a pen drive is a simple task. One end of the drive is equipped with a USB connector at one end. The connector is inserted into the USB port on a desktop or laptop and activated. Once the pen drive is in place, it is possible to drop and drag files into the memory of the drive, or forward the files to the drive. The process is no more difficult than attaching files to an email or copying files onto a disk.

Because there are several different operating systems in common use today, there are various types of levels of the pen drive that are configured to work with each system. Even persons who are using an older operating system can usually find a pen drive that is compatible. As long as the desktop or laptop is constructed with a USB port, and the pen drive is compatible with the operating system, the pen drive will provide practical and easy transmission of data from one hard drive to another one in a matter of minutes. 

Optical Disk

An optical disk is a compact disk or CD. The formatting of the optical disk will dictate whether it is a DVD, CD, read-only or rewritable. Optical disks have replaced vinyl records, cassette tapes, videotapes and floppy disks.

The optical disk became the preferred medium for music, movies and software programs because of its many advantages. Compact, lightweight, durable and digital, the optical disk also provides a minimum of 650 megabytes (MB) of data storage. A double-layered and double-sided DVD optical disk holds up to 15.9 gigabytes (GB) of data.

The optical disk is so named because its technology is based on light. As the disk spins, a laser beam follows a spiraling trail of pits and lands in the plastic material of the disk. The pits reflect light differently than the lands, while a device translates the reflective difference to bits of "on/off" or 1 and 0. The bits form bytes that carry the digital code of the data stored on the optical disk.

A standard optical disk measures 4.724 inches (120 mm) in diameter and .0472 inches (1.2 mm) in thickness. It is made from polycarbonate with a reflective layer of aluminum, coated in lacquer. The master optical disk is made from glass. Nickel stampers are produced from the glass master and used in an injection-molding machine to "press" or produce multiple copies of the optical disk for distribution. If the disk is double-layered, there will be stampers for each layer, after which the two layers must be bonded together. A double-sided disk requires different stampers for each side, in addition to each layer.

Notwithstanding music, movies and digital photographs, the optical disk is increasingly being used for data storage such as backup and archiving. Instant access to files and the ability to use a built-in DVD player all make the optical disk a superior choice over legacy tape backup units for the average computer user.

A blank optical disk can be purchased in many formats. The least expensive will be an audio CD, as these are single-sided, single layered, and not rewritable. DVDs are more expensive, with a double-sided, double-layered optical disk being the most expensive. Before purchasing this type of optical disk, be sure that your DVD player can handle the format. Blank disks are available nearly everywhere music, DVD movies and computers are sold, including discount department stores.  

Modem

Modem, short for modulator-demodulator is an electronic device that converts a computer’s digital signals into specific frequencies to travel over telephone or cable television lines. At the destination, the receiving modem demodulates the frequencies back into digital data. Computers use modems to communicate with one another over a network.

The modem has significantly evolved since the 1970s when the 300 baud modem was used for connecting computers to bulletin board systems (BBSs). With this type of modem each bit, represented digitally by a 1 or 0, was transmitted as a specific tone. The receiving modem responded with its own dedicated frequencies so that the modems could “talk at the same time.” The technical term for this type of modem is asynchronous.

While the 300 baud modem could transmit about 30-characters per second, fast enough for text-based BBSs, people were soon sharing programs and graphics. This required faster modems, and the modem went through many incarnations in rapid succession over the following three decades. By 1998 the standard dial-up modem maxed out its transmission range at 56 kilobits per second. While many tens of times faster than the 300-baud modem, far greater speeds could yet be reached with an Asymmetric Digital Subscriber Line (ADSL) modem.

The designation asymmetric simply means that the modem is faster at downloading (getting data), than uploading (sending data). The ADSL modem has significant, immediate advantages over the dial-up modem. Though it uses a standard telephone line like a dial-up modem, it does not tie up the line, making it possible to use the telephone while cruising the Internet. ADSL service is an “always on” connection, unlike a dial-up modem that cannot be left connected indefinitely. Finally, the ADSL modem is far faster than a dial-up modem.

The ADSL modem can accommodate a telephone conversation because of available bandwidth on the dedicated copper wire, which runs from households and businesses to the telephone company (Telco). A parallel can be made to a multi-lane freeway with several lanes open for additional traffic. The ADSL modem uses the additional lanes (higher frequencies) without interfering with existing voice traffic. An ADSL modem requires ADSL service through an Internet Service Provider (ISP). This type of modem will not work with a dial-up account.

Some businesses require as much bandwidth going upstream as downstream. This means they need to upload large files or programs to the Internet, as well as download large files. For equal bandwidth in both directions, one would need a Symmetric DSL (SDSL) account and SDSL modem. The SDSL modem uses voice traffic lanes to expand bandwidth, and therefore a conversation is not possible when the SDSL modem is connected. For this reason most businesses use a dedicated phone line with an SDSL modem.

Yet another type of modem uses cable TV wiring rather than the phone line to provide Internet connectivity. A cable modem requires service from a cable TV provider for Internet connectivity. The cable modem works on the same principle as the DSL modem, in that digital data is transferred across wires using frequencies that are translated back into digital data. Frequencies used for data traffic do not interfere with existing TV traffic.

A less common modem is a satellite modem, or sat modem. The satellite modem converts digital data into radio waves to communicate with a satellite dish. This not only involves a built-in latency factor in most cases, but the service is more expensive than more conventional types of Internet connectivity. A satellite modem can be an option, however, for businesses or enthusiasts in rural areas that do not yet have DSL or cable service offerings.

While most DSL and cable providers offer a modem with Internet service, the subscriber can also opt to provide his or her own modem. Often the Internet provider will make a list of compatible modems available, though these lists are rarely exhaustive. Online manuals for modems and technical specifications will also commonly list which Internet Service Providers the modem supports.

Touch Screen Monitors

Touch screen monitors are no longer confined to bar video games as novelty items. Today, they can be found in many stores as part of cash registers, in car dashboards and on many portable computers. With the growing popularity of touch screen enabled Palm Pilots and other PDAs, many people even have one in his or her pocket at all times.

The benefits of such technology are obvious. Rather than lugging along extra input devices such as a mouse or a keyboard, the user need only his finger to manipulate the chosen device. But it's not just mobile devices that benefit from this type of input. All kinds of devices can be equipped, including TV and computer monitors, LCD screens, and the older CRT computer monitors. As a result, a bartender can press on a screen to ring up drinks on a busy night rather than type in a price, a nurse can input patient information with one hand. Truly, the possibilities with touch screen monitors are endless.

Touch screen monitors usually come in three varieties that enable it to recognize a person's touch. These are resistive, capacitive and surface acoustic wave. The resistive type works by having two panels with a thin space between them. When the user presses the screen, the two panels touch at that point, and the exact coordinates are then registered with the computer.

A capacitive system runs a small electrical charge throughout the touch screen. When the user touches the chosen area, some of the electrical charge is distributed to the finger, lessening the charge at that location. The coordinates are again recorded and sent to the computer. This type of touch screen produces a clearer picture because it transmits more light and doesn't require two panels.

Finally, the surface acoustic wave system is the best, and results in the clearest picture. Transducers are used to send electrical signals across the screen, and if a user touches the screen, they can determine where based on how the electrical signal is received from one transducer to the other.

Since the capacitive system must have a finger to absorb electricity, most non-living objects won't register as a touch. Resistive and surface acoustic wave systems on the other hand react to just about any form of pressure. Each has its different advantages as a result, and manufacturers will only find new ways to make use of them.

Loudspeaker

A loudspeaker is simply a device that converts electrical energy into sound that is amplified so that it can be heard from a greater distance than the original sound would allow. There is no difference in usage of the terms speaker and loudspeaker and both are often used interchangeably. Some loudspeakers are capable of producing sounds over a wide range of frequencies and some are only made to reproduce certain frequencies.

While it may seem as though it is more desirable for a loudspeaker to transmit over the widest range of frequencies possible, there are advantages to those which have a limited range. Due to the size of the system needed to reproduce the broad spectrum of frequencies well, it may be harder to find a compact loudspeaker that can adequately handle the task. Therefore, many speakers trying to do all frequencies may do a substandard job of sound reproduction.

Having multiple speakers, with some specializing in different ranges of sound frequencies, offers some advantages. A loudspeaker designed to handle mid-range and upper-range sounds may be good for reproducing human voices and certain types of music. However, other speakers, such as the woofer and subwoofer, are designed to produce sounds of lower octaves.

A loudspeaker is classified as a woofer if it is meant to reproduce lower octaves of sound. A subwoofer is a loudspeaker that is meant to produce the lowest two to three octaves of sound. The subwoofer often looks like a box and is most likely the speaker prone to the most noticeable vibrations.

One of the most common uses of loudspeakers in the home environment is as home theater speakers. These speakers often are synchronized so they produce a surround sound effect and are often referred to as surround speakers. This is especially useful when watching movies, where the audio is often meant to be played on a surround sound system.

The quality of the loudspeaker greatly depends on the weight, and therefore the size, of the magnet inside the speaker. The larger the magnet, the more powerful the speaker will be. The weight of the magnet should be listed on the specifications of any good loudspeakers. However, it should be noted that some weigh the entire magnet system and not just the magnet itself. This could affect the power and quality of the speaker and deceive some into buying something other than what they thought they were purchasing

Concrete Mixer

A concrete mixer is a powered device that mixes cement with water and aggregate, such as sand or pea gravel, to make concrete. Concrete mixers range from the very large commercial mixing truck to the smaller, portable concrete mixer sometimes called a “mini mixer”. A concrete mixer is comprised primarily of a motor, a rotating drum, and often a chute. Inside the drum, the materials used to make concrete spin around, mixing together evenly and remaining soft for application and forming.

A large commercial concrete mixer truck is used for mixing and transporting large volumes of concrete for use on a building site. For smaller volumes of concrete, typically up to two cubic yards (1.83 cubic meters), a portable concrete mixer is sufficient. A portable concrete mixer is typically powered by electricity and sits on a base with wheels for easier transport. The rotating drum can be tilted down so that mixed concrete can be poured into a wheelbarrow.

For homeowners attempting small concrete projects such as a patio, sidewalk repair, or small slab, a portable concrete mixer is essential to maximize efficiency. A concrete mixer does not keep concrete ready for application indefinitely, so it is important to have an understanding of how much concrete you can pour and finish within a specific time frame. Different types of concrete set faster than others, so check the manufacturer’s directions.

Larger projects, such as a driveway or basketball court, may require calling a commercial truck. Commercial concrete mixers require access to within a fairly close distance of the project. In-ground swimming pools are an example of a large-scale project requiring direct access by a truck.

Understand that calling a concrete company only secures delivery of the concrete. Pricing is a flat rate per cubic yard ordered and the truck will remain on site only for a specified period of time. Large projects may require professional concrete finishers to accomplish the task within the time frame provided. Before calling a concrete company, be sure to have finishers on site and ready to pour, and don’t forget to obtain any permits necessary in your area.

Coffee Maker

A coffee maker is an electric countertop appliance that brews hot coffee automatically. It consists of a hot plate, a carafe or glass coffee pot, filter basket, and water reservoir.

A coffee maker is a very simple, low-tech, yet efficient machine. A heating element circles the hot plate at the bottom of the maker. Wrapped in this heating element is a hollow aluminum tube. When water is added to the reservoir, a small hole in the bottom of the container feeds a plastic hose that leads down to one end of the aluminum tube. Once the coffee maker is switched on, the heating element gets hot very quickly. Sensors cycle the element on and off to keep it 195-205 degrees Fahrenheit (90-96 Celsius). Water sitting in the aluminum tube boils and the turbulence creates bubbles that rise though the opposite end of the tube, traveling up an exit hose (making room for more water to enter the heating element). Hot water riding on these rising bubbles creates upward lift that carries a small stream of boiling water to the top of the coffee maker. Here the exit hose terminates on to a drip plate. The drip plate distributes the boiling water evenly to fall through to the coffee grounds below in the filter basket. Hence, the drip coffee maker fills the carafe with freshly brewed java.

If you buy coffee beans whole you can use a coffee grinder to prepare them. It is best to grind the beans just prior to brewing. A drip coffee maker uses medium to coarsely ground coffee, while finely ground coffee is used for making espresso. Note that espresso cannot be brewed in a drip coffee maker, but is made in an espresso machine.

Most coffee makers have a timer allowing them to turn on automatically. Some people prefer to prepare their coffee maker at night, setting the timer so they can wake to freshly made coffee in the morning. Though this is convenient, connoisseurs would not only object to grinding the coffee beans so many hours in advance, but would also point out that once the coffee is brewed it should be taken off the hot plate. Continued exposure to heat will bring out harsher flavors including bitterness.

Some coffee makers use steel filters, others use paper filters. Steel filters will allow more oils to pass, making coffee that is headier and has more body. Paper filters create cleaner, lighter coffee.

Experts say evidence suggests coffee Arabica originated in Ethiopia and has been cultivated for about 1500 years. Though coffee is brewed many different ways all over the world, today the coffee maker is by far the most popular way to brew a cup of Joe.