What Is the Difference Between Mbps and MBps

MBps is an abbreviation for Megabytes per second, whereas Mbps is an abbreviation for megabits per second. Eight megabits equal one Megabyte. These abbreviations are commonly used to specify how much data can be transferred per second between two points. In some cases, mbps is used as an abbreviation for megabits per second; however, the lowercase m technically means "milli" not "mega," so it doesn't really mean the same thing.

To put megabits and Megabytes in perspective, let's back up for just a moment. One bit of data is a single "on" or "off" digit, a one or zero. It takes eight bits to represent a single character, or one byte of data.

1. 8 bits = 1 byte
2. 1000 bytes = 8 kilobits (kb) = 1 Kilobyte (KB)
3. 1000 Kilobytes (KB) = 8 megabits (Mb) = 1 Megabyte (MB)

As a point of possible confusion it should be mentioned that there are two different systems for calculating multiples of data: the decimal system as noted above, and the binary system. 

According to the binary system, used in relation to computer storage and memory, it takes not 1000 bytes to equal a KB, but 1024 bytes. This is because the binary system is base 2, and 2¹⁰ = 1024. Technically, the designations in this case are Kibibyte (KiB) and Mebibyte (MiB), but these haven't caught on in the public sector, leading many uses of "MB" to mean 1024 kilobytes, and others to mean 1000 kilobytes. When considering MBps, however, the decimal system applies, as the reference is to data transfer rates and not data storage.

Data transfer rates are quite handy for gauging performance levels of various hardware devices. Everything from USB and Firewire® ports to memory card readers and mobile devices are associated with corresponding transfer rates, often measured in megabits or Megabytes per second. 

We must also translate speed to value when considering Internet service plans, advertised by download and upload speeds expressed in kilobits per second (kbps) or megabits per second. For example, a typical Digital Subscriber Line (DSL) plan might have an upper transfer limit of 1,500 kbps, which can also be expressed as 1.5 Mbps. A cable plan might be advertised with speeds up to 5,000 kbps or 5 Mbps; and fiber optic Internet can reach speeds of 50 Mbps or more. 

The wireless G network (802.11g) has a maximum transfer rate of 54 Mbps, making it much faster than all but the fastest fiber optic Internet plans. Thankfully, going wireless won’t slow your surfing. The more current wireless N standard (802.11n) can’t speed up your Internet connection, but will allow faster data transfer rates between local networked computers of up to 100 Mbps, or about twice the data transfer rate of G networks.

As if the abbreviations aren't close enough to cause confusion, it doesn’t help that they are often expressed in the wrong case. When in doubt look for translations such as the kilobit or Kilobyte equivalent, or simply ask someone if the specification is indeed megabits per second or Megabytes per second.

What Are Omnidirectional Microphones

Omnidirectional microphones can pick up sound from virtually any direction. This design can be useful when a device needs to pick up ambient sound or is used in an environment where sound sources are moving and it is not practical to move the microphone along with them. It does have some drawbacks, however, including muddy sound quality in some cases.

Microphone Design

The distinctive rounded end is a well-known characteristic of an omnidirectional microphone. The look is created by the bulging mesh installed over the electronic pick-up, which protects the internal electronics and can limit interference like breath noises and pops. Some omnidirectional microphones take this mesh covering one step further, with a cover made from foam used as a protective sleeve over the head of the device. The foam does not prevent sound from entering the mic, and also acts as a shield against wind and explosive breath sounds. The extreme sensitivity of omnidirectional microphones requires meticulous design to keep sound as crisp and clear as possible.

Wireless omnidirectional microphones that transmit signals without the use of a cable are also available. Small wireless mics called lavaliers are usually clipped to the speaker's lapel or blouse and fed to either a concealed wireless transmitter or a channel on an audio mixing board. Omnidirectional lavalier microphones also have the distinctive round shape of their larger counterparts.

Uses

The most common uses of an omnidirectional microphone involve groups of singers or instrumentalists. A microphone can be suspended from the ceiling above a choral group or positioned between a vocalist and an accompanying piano or guitar. Solo performers can hold an omnidirectional microphone in various positions and still be amplified.

This equipment can also be useful for meetings and events where there may be multiple speakers but a single microphone, or where it is important to capture sound from several angles. As different speakers add to the conversation or change position, the microphone will still be able to pick up their voices. The alternative is tracking individual speakers with unidirectional mics, which can be time-consuming and expensive, especially for small organizations that don’t have a large budget for sound equipment.

Potential Advantages

Omnidirectional microphones can be very easy to set up and use, even by inexperienced people who may not have used one before. As a result, someone with little or no experience can usually manage the set up, helping to reduce expenses for an event. This can be helpful at events where attendees may need to use a microphone to speak, like town hall meetings and wedding parties.

The broad pickup abilities of an omnidirectional microphone also make it very usable in environments where wide coverage is needed or where the precise origins of sounds may not yet be known. For example, someone recording wildlife might use an omnidirectional microphone to pick up general sounds and background noises because he or she cannot predict how the subjects might move.

Low-cost options with relatively high quality are also available. This can be useful for organizations concerned about budget, or people starting to learn about sound systems who are not able to invest in expensive specialized equipment. An omnidirectional microphone can be used in a variety of applications, while a more focused unidirectional device is less flexible.

Potential Disadvantages

Ideally, an omnidirectional mic would pick up sound in a perfect circle around its center. The laws of physics make this somewhat challenging, however, and in real-world use, this type of microphone cannot pick up sound perfectly from every direction. It can also cut out some high and low frequencies, and sound coming from an extreme angle may not be reliably detected.

The inability to discriminate between wanted and unwanted sounds means that ambient noise can be picked up and amplified. Some performers may want the sounds of an enthusiastic audience to be included in the session, for instance, but others may want these noises blocked out. A unidirectional microphone may be better at keeping background noise out of the recording and amplifying equation.

Another risk with omnidirectional microphones involves the triangle between the microphone, the performer, and the speakers. If an omnidirectional microphone is placed too close to the speakers, it will pick up extraneous noise. This noise is then fed back into the system through the microphone and amplified again. The result is a very unpleasant phenomenon called a feedback loop. Great care must be taken to avoid putting an omnidirectional microphone directly in front of the speakers.

Unidirectional Microphones

The design of an omnidirectional microphone contrasts with unidirectional microphones, which only pick up sound from a more targeted source. There are several different types of unidirectional mics, each classified by its polar pattern or directionality — the shape created when the sound pickup is mapped on a flat plane. Some options can include a shotgun microphone, which is a highly directional device intended for pointing at a specific point source of sound; and a cardioid, which is named for the heart-like shape of its polar pattern. While multiple unidirectional microphones can offer better sound quality in some cases by capturing specific sources with less background noise, they can be expensive and more difficult to set up correctly.

What is a Multiplexer

A multiplexer, sometimes referred to as a multiplexor or simply a mux, is an electronic device that selects from several input signals and transmits one or more output signals. In its simplest form, a multiplexer will have two signal inputs, one control input and one output. One example of an analog multiplexer is the source control on a home stereo unit that allows the user to choose between the audio from a compact disc (CD) player, digital versatile disc (DVD) player and cable television line, for example.

Multiplexers also are used in building digital semiconductors such as central processing units (CPUs) and graphics controllers. In these applications, the number of inputs is generally a multiple of two, the number of outputs is either one or relatively small multiple of two, and the number of control signals is related to the combined number of inputs and outputs. For example, a two-input, one-output multiplexer requires only one control signal to select the input, and a 16-input, four-output multiplexer requires four control signals to select the input and two to select the output.

Types of multiplexers also are used in communications. A telephone network is an example of a very large virtual multiplexer that is built from many smaller, discrete ones. Instead of having a direct connection from every telephone to every other telephone — which would be physically impossible — the network muxes individual telephone lines onto a small number of wires as calls are placed. At the receiving end, a demultiplexer, or demux, chooses the correct destination from the many possible destinations by applying the same principle in reverse.

There are more complex forms of multiplexers. Time-division multiplexers, for example, have the same input/output characteristics as other multiplexers, but instead of having control signals, they alternate between all possible inputs at precise time intervals. By taking turns in this manner, many inputs can share one output. This technique is commonly used on long-distance phone lines, allowing many individual phone calls to be spliced together without affecting the speed or quality of any individual call. Time-division multiplexers generally are built as semiconductor devices, or chips, but they also can be built as optical devices for fiber optic applications.

Even more complex are code-division multiplexers. Using mathematical techniques developed during World War II for cryptographic purposes, they have since found application in modern code division multiple access (CDMA) cellular networks. These semiconductor devices work by assigning each input a unique complex mathematical code. Each input applies its code to the signal that it receives, and all signals are simultaneously sent to the output. At the receiving end, a demux performs the inverse mathematical operation to extract the original signals.

What is a Potentiometer

A potentiometer is a manually adjustable electrical resistor that uses three terminals. In many electrical devices, potentiometers are what establish the levels of output. For example, in a loudspeaker, a potentiometer is used to adjust the volume. In a television set, computer monitor or light dimmer, it can be used to control the brightness of the screen or light bulb.

How It Works

Potentiometers, sometimes called pots, are relatively simple devices. One terminal of the potentiometer is connected to a power source, and another is hooked up to a ground — a point with no voltage or resistance and which serves as a neutral reference point. The third terminal slides across a strip of resistive material. This resistive strip generally has a low resistance at one end, and its resistance gradually increases to a maximum resistance at the other end. The third terminal serves as the connection between the power source and ground, and it usually is operated by the user through the use of a knob or lever.

The user can adjust the position of the third terminal along the resistive strip to manually increase or decrease resistance. The amount of resistance determines how much current flows through a circuit. When used to regulate current, the potentiometer is limited by the maximum resistivity of the strip.

Controlling Voltage

Potentiometers also can be used to control the potential difference, or voltage, across circuits. The setup involved in utilizing a potentiometer for this purpose is a little more complicated. It involves two circuits, with the first circuit consisting of a cell and a resistor. At one end, the cell is connected in series to the second circuit, and at the other end, it is connected to a potentiometer in parallel with the second circuit.

The potentiometer in this arrangement drops the voltage by an amount equal to the ratio between the resistance allowed by the position of the third terminal and the highest possible resistivity of the strip. In other words, if the knob controlling the resistance is positioned at the exact halfway point on the resistive strip, then the output voltage will drop by exactly 50 percent, no matter what the input voltage is. Unlike with electrical current regulation, voltage regulation is not limited by the maximum resistivity of the strip.

Rheostats

When only two of the three terminals are used, the potentiometer acts as a type of variable resistor called a rheostat. One end terminal is used, along with the sliding terminal. Rheostats typically are used to handle higher levels of current or higher voltage than potentiometers. For example, rheostats might be used to control motors in industrial machinery.

What Should I Do if I Drop My Cell Phone in Water

If you drop your cell phone in water, it is often possible to salvage it. Time is of the essence, however, so the first thing to do is to get your cell phone out of the water as soon as possible. Leaving a cell phone in water for even a few seconds might damage it beyond repair, but there are a few things that you can try and that sometimes work. The main things are opening the phone as much as possible, taking out the battery and completely drying off all of the components.

Remove the Battery

After retrieving your cell phone from the water, the next thing to do is to remove the battery immediately, without even hesitating to turn off the power. This reduces the risk of a short circuit that would render your phone useless. Dry the battery with a towel, and it set aside to dry thoroughly. The battery itself might not work again, but it can be replaced fairly inexpensively. Even if the battery does work, it is a good idea to get a new one to avoid the risk of having the old one leak battery acid.

Take It Apart

After you have removed the battery, dry off the cell phone with an absorbent towel as best as you can. Use cotton swabs to soak up water in crevices and on any fragile, exposed circuits. If you have dropped your cell phone in water, it also is helpful to disassemble it, if you can, and let all of the parts dry separately. Just be sure that you know how to put it back together. If it is a flip or sliding cell phone, leave it open to allow for maximum evaporation.

Avoid Mineral Damage

If you drop your cell phone in water that isn't pure or another liquid, such as a beverage or in salt water, rinse off the phone with fresh water after you have removed the battery. After you drop your cell phone in water, a quick rinsing is unlikely to do any further damage, but salt, sugar or other materials might. You also could try giving your phone an alcohol bath. The alcohol will displace minerals and microscopic substances and will aid in the evaporation of the fluid. If it is available, you should use an alcohol concentration of 95 percent rather than rubbing alcohol, which usually has a concentration of 70 percent.

Let It Dry

After your phone is clean, leave it in a warm, dry area or near an air conditioner for at least three days before you attempt to replace the battery and turn it on. This is very important, because although you may think that you have thoroughly dried it, the slightest moisture can react with the battery and cause it to short circuit. Putting your cell phone in a container full of dry rice grains also can help dry it out. Make sure that the rice completely covers the phone.

Warranty Likely Voided

Unless you have insurance for your cell phone and it covers water damage, there probably is no point in sending it to the manufacturer with the hope that the warranty will cover the cost of a replacement. If you drop your cell phone in water, the warranty probably will be voided. The manufacturer's technicians will be able to tell immediately that it has been dropped in water because of the moisture-sensitive stickers that are placed inside almost all cell phones. The best thing to do is to dry it out yourself and hope that it still works.

Do Batteries Really Last Longer if They Are Stored in the Refrigerator

Some household batteries may last slightly longer if stored in the refrigerator or freezer. Even when not being used, the internal components slowly corrode over time; cool temperatures can slow down this process. The type of battery and how it is stored will greatly affect whether refrigeration is an efficient means of extending its shelf life, however. Rechargeable varieties get more benefit from the cooler temperatures than alkalines do. All types of batteries must be protected from moisture in the refrigerator, so they should be kept in a sealed container.

Refrigerating Alkaline Models

Since most manufacturers recommend storing batteries in a cool, dry location to last as long as possible, it may seem logical to keep alkaline models in the refrigerator. Most refrigerators maintain an average temperature of 40° Fahrenheit (approximately 10° Celsius) or lower, and the atmosphere inside is very low in humidity. This seems like an ideal storage environment, as the lower temperature reduces the power drain on the electrolyte fluid inside the battery, which acts as a medium for the flow of the electrical current. According to the results of several tests, storage at very cold temperatures will increase the shelf life, but only by a small amount. Alkaline models stored in a refrigerator can retain 93% of their power after five years, compared to 90% for non-refrigerated models stored in other cool, dry areas.

The downsides of refrigeration for alkaline varieties may outweigh the minor extension in their shelf life. Although a refrigerator has low humidity, batteries that are not sealed in an air-tight container may be subject to contact with moisture from other items in the refrigerator, which can destroy the electrical circuit. Extremely cold temperatures can also corrode the contact points on either end of the battery, rendering them unusable. One of the biggest downsides is that the batteries must be returned to room temperature before they can be used, so they cannot simply be taken out of cold storage and put immediately into electronics.

Refrigerating Rechargeable Models

Rechargeable varieties, such as nickel-metal hydride (NiMh), can benefit greatly from cold storage when cared for properly. While rechargeable models offer many advantages over alkaline varieties, they suffer from a fairly short charge life, and may need to be charged every few days when stored at room temperature. Carefully stored in the refrigerator, a rechargeable battery can hold at a 90% charge for months at a time.

For best results, rechargeable batteries need to be kept in a sealed freezer bag inside an airtight container to reduce the risk of moisture damage or condensation. Any moisture can cause corrosion inside of the battery, making it unusable. Like alkaline models, rechargeables will need to be thawed before they can be used.

Other Ways to Extend Shelf Life

People who are concerned about getting the most use out of their batteries should consider investing in rechargeable models, which can be used dozens of times without replacing. This not only cuts down on the cost of supplies over time, but is also more environmentally friendly. Recharging the batteries before they are completely depleted can also extend their lifespan, as draining a battery fully usually causes it to wear down more quickly.

It is also best to use the right type of battery for specific electronics. Some devices, such as digital cameras, use up a lot of power quickly, and eat up regular alkaline varieties in just a few hours. Some batteries are built to withstand the increased power needs of high-drain electronics, so they should be used to reduce costs.

Batteries should be removed from electronic devices when they are not in use to extend their life. Most electronics draw small amounts of power even when they are turned off, sometimes called "vampire power" or "phantom load." These electronics will drain batteries over time. For rarely used devices, removing the batteries can cut down on energy costs.

Rather than worrying too much about refrigeration, most users get more benefit from finding a cool location with low humidity to store their batteries. While cold storage may extend the shelf life slightly, exposure to heat and humidity will cause a much more rapid decline. Some experts recommend avoiding storing batteries in the kitchen, since using the stove can cause frequent and rapid temperature jumps. Cool closets that do not receive much light are often excellent storage locations.

What Is HDMI®

HDMI® (High-Definition Multimedia Interface) is an interface standard used for audiovisual equipment such as high-definition television and home theater systems. With 19 wires wrapped in a single cable that resembles a USB wire, HDMI® is able to carry a bandwidth of 5 Gbps (gigabits per second). This is more than twice the bandwidth needed to transmit multi-channel audio and video, future-proofing HDMI® for some time to come. This and several other factors make HDMI® much more desirable than its predecessors, component video, S-Video and composite video. 

HDMI® is an uncompressed, all-digital signal, while the aforementioned interfaces are all analog. With an analog interface, a clean digital source is translated into less precise analog, sent to the television, then converted back to a digital signal to display on screen. At each translation, the digital signal loses integrity, resulting in some distortion of picture quality. HDMI® preserves the source signal, eliminating analog conversion to deliver the sharpest, richest picture possible. 

Previous video interfaces required separate audio cables, with the vast majority of people using standard RCA L/R analog audio jacks. HDMI®, with its abundant bandwidth and speed, carries not only video but also up to eight digital audio channels for uncompromised surround-sound. It replaces the tangle of wires behind the system with a single cable, greatly simplifying the entire setup process of the home theater system while delivering top tier performance. 

Though standard HDMI® or "Type A" has 19 wires, "Type B" will have 29 wires. The latter is targeted for the motion picture industry and other professional applications. Both varieties are "Intelligent HDMI®," referring to the built-in capability for HDMI®-enabled components to talk to each other via the interface. Auxiliary information can provide all-in-one remote functionality and other interoperable features not possible in previous interface technologies.

HDMI® supports standard video formats, enhanced video and high-definition. It is also backwards compatible with DVI (Digital Video Interface). High-end graphics cards featuring a DVI port can connect to a HDMI® interface via a DVI/HDMI® cable. This is simply a cable with a DVI connector on one end and a HDMI® connector on the other. As a rule, HDMI® cables should not run longer than 15 feet (5 meters), or degradation of the signal could occur.

As of 2005, many high-end television sets were sold with at least one HDMI® interface. Some experts advise that two HDMI® interfaces will provide more flexibility, and for those who want to connect a game console, three might serve better. Multiple interfaces will become common on digital TVs as the industry incorporates HDMI® interfaces into more peripheral components.