What is Ohm’s Law?

German physicist Georg Ohm uncovered how a material's make up, length and thickness influences how much current will flow through it at a certain voltage.
German physicist Georg Ohm uncovered how a material’s make up, length and thickness influences how much current will flow through it at a certain voltage.

Ohm’s Law is a law used in physics that basically explains how electricity operates properly within a simple circuit. In order to explain the electrical process, the law shows how the three elements of electricity — ampere, resistance, and voltage — work together to create a functioning electrical circuit. The law states that the amount of electrical current, measured in amperes, traveling through a conductor is proportional or equal to the voltage, but is inversely proportional to the resistance in the conductor.

The proponent and the namesake of the law was George Simon Ohm, a renowned German physicist in the early 1800s. While working as a professor at the Jesuit Gymnasium of Cologne in Germany, he experimented with and observed the behavior of electricity in simple circuits with different wire lengths. He described and documented all the results in a book, “The Galvanic Circuit Investigated Mathematically,” which was initially rejected but later acknowledged, leading to the establishment of the Ohm’s Law.

Ohm’s Law can be written in a simple mathematical equation: I = V/R, where I is for the electrical current measured in amperes, V is for the voltage, and R is for the resistance. In this equation, the resistance is usually a constant variable, since its value is not dependent on the amount of electric current, but rather on the materials used to make the circuit, such as the metal wires and the resistor itself. The formula can be expressed in other inversed forms such as V = IR, or R = V/I. These inversed formulas can help find the value of one element if the values of the two other elements are already identified.

There are essentially three “truth” statements that one should remember regarding Ohm’s Law. The first statement is that the value of I will increase or decrease if the value of V increases or decreases, respectively. The second statement is that the value of I will decrease if the value of R increases and the value of V does not change. The third statement is that the value of I will increase if the value of R decreases and the value of V remains the same.

Ohm's Law can be used to find the electrical resistance applied to a circuit by resistors.
Ohm’s Law can be used to find the electrical resistance applied to a circuit by resistors.


The principle of Ohm’s Law can be practically applied in appliances and any equipment operated by electricity or a battery. For example, a simple light-emitting diode (LED) needs only 2 volts and .02 amperes to light up, but is connected to a 6-volt battery. This may cause the LED to short circuit, and a resistor is needed to reduce the current. Using the formula R = V/I, one can determine that a resistor containing 200 ohms is needed to control the current coming into the LED.


Source / Courtesy : WiseGeek

Entanglement : promises secure & faster computers

[dropcap]U[/dropcap]nlike Bilbo’s magic ring, which entangles human hearts, engineers have created a new micro-ring that entangles individual particles of light, an important first step in a whole host of new technologies.

Entanglement — the instantaneous connection between two particles no matter their distance apart — is one of the most intriguing and promising phenomena in all of physics. Properly harnessed, entangled photons could revolutionize computing, communications, and cyber security. Though readily created in the lab and by comparatively large-scale optoelectronic components, a practical source of entangled photons that can fit onto an ordinary computer chip has been elusive.

New research, reported today in The Optical Society’s (OSA) new high-impact journal Optica, describes how a team of scientists has developed, for the first time, a microscopic component that is small enough to fit onto a standard silicon chip that can generate a continuous supply of entangled photons.

The new design is based on an established silicon technology known as a micro-ring resonator. These resonators are actually loops that are etched onto silicon wafers that can corral and then reemit particles of light. By tailoring the design of this resonator, the researchers created a novel source of entangled photons that is incredibly small and highly efficient, making it an ideal on-chip component.

“The main advantage of our new source is that it is at the same time small, bright, and silicon based,” said Daniele Bajoni, a researcher at the Università degli Studi di Pavia in Italy and co-author on the paper. “The diameter of the ring resonator is a mere 20 microns, which is about one-tenth of the width of a human hair. Previous sources were hundreds of times larger than the one we developed.”

From Entanglement to Innovation

Scientists and engineers have long recognized the enormous practical potential of entangled photons. This curious manifestation of quantum physics, which Einstein referred to as “spooky action at a distance,” has two important implications in real-world technology.

First, if something acts on one of the entangled photons then the other one will respond to that action instantly, even if it is on the opposite side of a computer chip or even the opposite side of the Galaxy. This behavior could be harnessed to increase the power and speed of computations. The second implication is that the two photons can be considered to be, in some sense, a single entity, which would allow for new communication protocols that are immune to spying.

This seemingly impossible behavior is essential, therefore, for the development of certain next-generation technologies, such as computers that are vastly more powerful than even today’s most advanced supercomputers, and secure telecommunications.

Creating Entanglement on a Chip

To bring these new technologies to fruition, however, requires a new class of entangled photon emitters: ones that can be readily incorporated into existing silicon chip technologies. Achieving this goal has been very challenging.

To date, entangled photon emitters — which are principally made from specially designed crystals — could be scaled down to only a few millimeters in size, which is still many orders of magnitude too large for on-chip applications. In addition, these emitters require a great deal of power, which is a valuable commodity in telecommunications and computing.

To overcome these challenges, the researchers explored the potential of ring resonators as a new source for entangled photons. These well-established optoelectronic components can be easily etched onto a silicon wafer in the same manner that other components on semiconductor chips are fashioned. To “pump,” or power, the resonator, a laser beam is directed along an optical fiber to the input side of the sample, and then coupled to the resonator where the photons race around the ring. This creates an ideal environment for the photons to mingle and become entangled.

As photons exited the resonator, the researchers were able to observe that a remarkably high percentage of them exhibited the telltale characteristics of entanglement.

“Our device is capable of emitting light with striking quantum mechanical properties never observed in an integrated source,” said Bajoni. “The rate at which the entangled photons are generated is unprecedented for a silicon integrated source, and comparable with that available from bulk crystals that must be pumped by very strong lasers.”

Applications and Future Technology

The researchers believe their work is particularly relevant because it demonstrates, for the first time, a quintessential quantum effect, entanglement, in a well-established technology.

“In the last few years, silicon integrated devices have been developed to filter and route light, mainly for telecommunication applications,” observed Bajoni. “Our micro-ring resonators can be readily used alongside these devices, moving us toward the ability to fully harness entanglement on a chip.” As a result, this research could facilitate the adoption of quantum information technologies, particularly quantum cryptography protocols, which would ensure secure communications in ways that classical cryptography protocols cannot.

According to Bajoni and his colleagues, these protocols have already been demonstrated and tested. What has been missing was a cheap, small, and reliable source of entangled photons capable of propagation in fiber networks, a problem that is apparently solved by their innovation.

Story Source:

The above story is based on materials provided by The Optical Society. Note: Materials may be edited for content and length.

Journal Reference:

  1. Davide Grassani, Stefano Azzini, Marco Liscidini, Matteo Galli, Michael J. Strain, Marc Sorel, J. E. Sipe, Daniele Bajoni. Micrometer-scale integrated silicon source of time-energy entangled photons. Optica, 2015; 2 (2): 88 DOI:10.1364/OPTICA.2.000088

Get an Understanding of Computer Terms

If you’re upgrading your PCs, you might run into many IT terms and computer-related words and phrases that are difficult to understand. We’re to help you know what you’re getting!


Also known as ‘chip’ or ‘CPU’, the processor controls everything your computer does. It lets you do several things like work, email and surf – all at the same time. More powerful processors are better for more demanding tasks so get one that performs a little above your current needs.



The computer uses random access memory (RAM) to process what the user is doing as they are doing it. This includes multitasking, writing a letter, editing a photo or browsing a web site. 4GB of RAM should be enough for most of your everyday needs, and you can always upgrade and add more RAM later.

Hard Drive

Think of the Hard Disk Drive (HDD) as your computer’s long-term memory. It acts as a filing cabinet for your documents, data, media files and so on. The size or capacity of a hard drive is measured in gigabytes. If you plan on storing a lot of videos and other big files, get a larger hard drive. Another option is to purchase an external USB 2.0 hard drive. Some new notebook PCs now use solid-state drives (SSD) with no moving parts, making them more resistant to shock, quieter and with faster information access.

Processor Number

Acting like a serial number, the processor number differentiates features within a processor family, with a higher number generally indicating more features. You can use this number to verify that your chosen processor includes the features you want. Keep in mind that processor numbers do not work across different processor families.

Intel® HD Graphics

Available as a built-in visual feature on selected Intel® Core™ processors, Intel® HD Graphics enables discrete 3D graphics performance without the added cost of a separate graphics card. You’ll enjoy crisp images with the highest frames per second for mainstream videos.00612012015

Intel® Quick Sync Video

Intel® Quick Sync Video accelerates hardware performance during video editing, burning and sharing to significantly reduce waiting time from hours to just minutes.

Intel® InTru™ 3D Technology

Watch Blu-ray videos in stereo 3D and full 1080p resolution on your computer with Intel® InTru™ 3D Technology.

00712012015Intel® Turbo Boost Technology 2.0

A feature available on selected 4th gen Intel® Core™ processors, Intel® Turbo Boost Technology 2.0 automatically provides an even greater boost of speed to reduce lag time to meet the heavy processing demands of high-end apps.

Integrated Graphics

A graphics component needed to view images. Integrated graphics offers the performance for everyday tasks like watching HD videos, viewing photos and creating presentations. Standard in selected Intel® Core™ processors, integrated graphics improve graphics performance and notebook battery life.

Intel® Clear Video Technology00812012015

Intel® Clear Video Technology delivers higher visual performance for sharper images, richer colour and superior audio and video playback.

Intel® Wireless Display

This built-in visual feature allows you to wirelessly view your personal content, online TV programmes, films and videos on your home TV screen.

00912012015Clock Speed

Just like a stopwatch, clock speed measures how fast your processor performs one activity cycle. A faster clock speed enables your computer to execute instructions more quickly, benefitting most applications from spreadsheets to video editing and more. Clock speed rates are shown in gigahertz (GHz). (See GHz)

Gigahertz (GHz)

A unit to measurement commonly used to express processor speed, also referred to as clock speed. 1 Gigahertz (GHz) = 1 billion cycles per second. A higher number used to mean a faster processor, but advances in technology have made chips more efficient. For this reason it’s not advisable to compare performance based on GHz or clock speed alone. (See Clock Speed)

nm (nanometre)

A unit of measure, a nanometre (nm) is one-billionth of a metre. The transistors on Intel’s latest processors are just 32nm wide, with older models at 45nm and 65nm. The smaller size allows transistors to be packed more densely, leak less energy, produce less heat and switch faster, so processors run faster, use less power and are more energy-efficient.

Intel® Hyper-Threading Technology

Available on selected Intel® processors, Intel® Hyper-Threading Technology makes more efficient use of your processor so you can run demanding applications while maintaining system responsiveness. With this technology, multimedia enthusiasts can create, edit and encode heavy graphics files while running other applications, without losing performance.

Cores and Threads01012012015

Cores and threads go hand-in-hand. Multi-core processors are single chips that contain two or more distinct processors or execution cores in the same integrated circuit. Multi-threading allows each core to work on two tasks at once, letting you do more things at the same time for faster results.

Built-In Visuals

A group of technology features designed to enhance the visual experience delivered by the Intel® Core™ processors. Built-in visual features include Intel® Quick Sync Video, Intel® HD Graphics, Intel® Clear Video Technology and Intel® InTru™ 3D Technology.

Discrete Graphics

This graphics component comes as an additional graphics card. While ideal for high-end 3D designers and video editors, it doesn’t add much performance for most business users. It’s important to note that only more powerful processors can make full use of discrete graphics.

Intel® Smart Cache

A cache is a fast storage area where the processor keeps frequently accessed data. Intel® Smart Cache maximises this data storage. It allows each processor core to utilise up to 100% of the space and pull data faster, improving overall performance for rich media applications and games.


Quantum optical hard drive breakthrough

This image shows quantum information being written on to the nuclear spins of a europium ion. Credit: Solid State Spectroscopy Group, ANU
This image shows quantum information being written on to the nuclear spins of a europium ion.
Credit: Solid State Spectroscopy Group, ANU

Scientists developing a prototype quantum hard drive have improved storage time by a factor of more than 100.

The team’s record storage time of six hours is a major step towards a secure worldwide data encryption network based on quantum information, which could be used for banking transactions and personal emails.

“We believe it will soon be possible to distribute quantum information between any two points on the globe,” said lead author Manjin Zhong, from the Research School of Physics and Engineering (RSPE) at The Australian National University (ANU).

“Quantum states are very fragile and normally collapse in milliseconds. Our long storage times have the potential to revolutionise the transmission of quantum information.”

Quantum information promises unbreakable encryption because quantum particles such as photons of light can be created in a way that intrinsically links them. Interactions with either of these entangled particles affect the other, no matter how far they are separated.

The team of physicists at ANU and the University of Otago stored quantum information in atoms of the rare earth element europium embedded in a crystal.

Their solid-state technique is a promising alternative to using laser beams in optical fibres, an approach which is currently used to create quantum networks around 100 kilometres long.

“Our storage times are now so long that it means people need to rethink what is the best way to distribute quantum data,” Ms Zhong said.

“Even transporting our crystals at pedestrian speeds we have less loss than laser systems for a given distance.”

“We can now imagine storing entangled light in separate crystals and then transporting them to different parts of the network thousands of kilometres apart. So, we are thinking of our crystals as portable optical hard drives for quantum entanglement.”

After writing a quantum state onto the nuclear spin of the europium using laser light, the team subjected the crystal to a combination of a fixed and oscillating magnetic fields to preserve the fragile quantum information.

“The two fields isolate the europium spins and prevent the quantum information leaking away,” said Dr Jevon Longdell of the University of Otago.

The ANU group is also excited about the fundamental tests of quantum mechanics that a quantum optical hard drive will enable.

“We have never before had the possibility to explore quantum entanglement over such long distances,” said Associate Professor Matthew Sellars, leader of the research team.

“We should always be looking to test whether our theories match up with reality. Maybe in this new regime our theory of quantum mechanics breaks.”

Story Source:

The above story is based on materials provided by Australian National University.Note: Materials may be edited for content and length.

Journal Reference:

  1. Manjin Zhong, Morgan P. Hedges, Rose L. Ahlefeldt, John G. Bartholomew, Sarah E. Beavan, Sven M. Wittig, Jevon J. Longdell, Matthew J. Sellars. Optically addressable nuclear spins in a solid with a six-hour coherence time. Nature, 2015; 517 (7533): 177 DOI: 10.1038/nature14025

Understanding Wi-Fi Speeds


Wi-Fi speeds are designated by letter, not by number. Unlike the easy to translate number-as-network-speed designation we find with Ethernet the Wi-Fi designations actually refer to the draft versions of the IEEE 802.11 networking standard that dictates the parameters of the Wi-Fi protocol.

802.11b was the first version widely adopted by consumers. 802.11b devices operate at a maximum transmission of 11 Mbit/s but the speed is highly dependent on signal strength and quality—realistically users should expect 1-5 Mbit/s. Devices using 802.11b suffer from interference from baby monitors, bluetooth devices, cordless phones, and other 2.4GHz band devices.

802.11g was the next major consumer upgrade and boosted the max transmission to 54 Mbit/s (realistically about 22 Mbit/s accounting for error correction and signal strength). 802.11g suffers from the same kind of 2.4GHz band interference that 802.11b does.

802.11n is a significant upgrade to the Wi-Fi standards—devices use multiple-input multiple-output antennas (MIMO) to operate on both the 2.4GHz and relatively empty 5GHz bands. 802.11n has a theoretical maximum of 300 Mbit/s but accounting for error correction and less than ideal conditions you can expect speeds in 100-150 Mbit/s range.

802.11ac is a huge upgrade that brings wider channels (80 or 160 MHz versus 40 MHz), more spatial streams (up to eight) and things like beamforming, which sorta send the waves directly to your device instead of bouncing all around, making things much faster. How much faster? There are some models that can do one gigabit per second. It’s extremely fast.

Like Ethernet, Wi-Fi speeds are limited by the weakest link in the direct network. If you have an 802.11n capable Wi-Fi router but your netbook only has an 802.11g capable Wi-Fi module you will max out at the 802.11g speeds. In addition to the speed limitations there is a very pressing reason for abandoning the oldest popular Wi-Fi protocol 802.11b. You must use the same level of encryption on every device in your network and the encryption schemes available to 802.11b devices are weak and have been compromised (WEP encryption, for example, can be compromised in a matter of minutes by a moderately skilled child). Upgrading your Wi-Fi router and wireless equipment allows you to upgrade your wireless encryption as well as enjoy faster speeds. If you haven’t done anything to secure your router now would be a good time to read our guide to locking down your Wi-Fi network against intrusion.

Also like Ethernet, upgrading to the maximum speed—in this case 802.11n—is best suited for people moving large files and streaming HD video. Upgrading to 802.11n will have a negligible impact on your web browsing speed but will have an enormous impact on your ability to wirelessly stream HD content around your home.

How To Secure Your Wi-Fi Network Against Intrusion


Insecure Wi-Fi is the easiest way for people to access your home network, leech your internet, and cause you serious headaches with more malicious behavior. Read on as we show you how to secure your home Wi-Fi network.

Why Secure Your Network?

In a perfect world you could leave your Wi-Fi networks wide open to share with any passing Wi-Fi starved travelers who desperately needed to check their email or lightly use your network. In reality leaving your Wi-Fi network open create unnecessary vulnerability wherein non-malicious users can sponge up lots of our bandwidth inadvertently and malicious users can pirate using our IP as cover, probe your network and potentially get access to your personal files, or even worse. What does even worse look like?  In the case of Matt Kostolnik it looks like a year of hell as your crazy neighbor, via your hacked Wi-Fi network, uploads child pornography in your name using your IP address and sends death threats to the Vice President of the United States. Mr. Kolstolnik was using crappy and outdated encryption with no other defensive measures in place; we can only imagine that a better understanding of Wi-Fi security and a little network monitoring would have saved him a huge headache.

Securing Your Wi-Fi Network


Securing your Wi-Fi network is a multi-step affair. You need to weigh each step and decide if the increased security is worth the sometimes increased hassle accompanying the change. To help you weigh the benefits and drawbacks of each step we’ve divided them up into relative order of importance as well as highlighted the benefits, the drawbacks, and the tools or resources you can use to stress test your own security. Don’t rely on our word that something is useful; grab the available tools and try to kick down your own virtual door.

Note: It would be impossible for us to include step-by-step instructions for every brand/model combination of routers out there. Check the brand and model number on your router and download the manual from the manufacturer’s website in order to most effectively follow our tips. If you have never accessed your router’s control panel or have forgotten how, now is the time to download the manual and give yourself a refresher.

Update Your Router and Upgrade to Third Party Firmware If Possible: At minimum you need to visit the web site for the manufacture of your router and make sure there are no updates. Router software tends to be pretty stable and releases are usually few and far between. If your manufacturer has released an update (or several) since you purchased your router it’s definitely time to upgrade.

Even better, if you’re going to go through the hassle of updating, is to update to one of the awesome third-party router firmwares out there like DD-WRT or Tomato. The third party firmwares unlock all sorts of great options including an easier and finer grain control over security features.

The hassle factor for this modification is moderate. Anytime you flash the ROM on your router you risk bricking it. The risk is really small with third-party firmware and even smaller when using official firmware from your manufacturer. Once you’ve flashed everything the hassle factor is zero and you get to enjoy a new better, faster, and more customizable router.

Change Your Router’s Password: Every router ships with a default login/password combination. The exact combination varies from model to model but it’s easy enough to look up the default that leaving it unchanged is just asking for trouble. Open Wi-Fi combined with the default password is essentially leaving your entire network wide open. You can check out default password lists here, here, and here.

The hassle factor for this modification is extremely low and it’s foolish not to do it.


Turn On and/or Upgrade Your Network Encryption: In the above example we gave, Mr. Kolstolnik had turned on the encryption for his router. He made the mistake of selecting WEP encryption, however, which is the lowest encryption on the Wi-Fi encryption totem pole. WEP is easy to crack using freely available tools such as WEPCrack and BackTrack. If you happened to read the entire article about Mr. Kolstolnik’s problems with his neighbors you’ll note that it took his neighbor two weeks, according to the authorities, to break the WEP encryption. That’s such a long span of time for such a simple task we have to assume that he also had to teach himself how to read and operate a computer too.

Wi-Fi encryption comes in several flavors for home use such as WEP, WPA, and WPA2. In addition WPA/WPA2 can be further subdivided as WPA/WPA2 with TKIP (a 128-bit key is generated per packet) and AES (a different 128-bit encryption). If possible you want to use WP2 TKIP/AES as AES is not as widely adopted as TKIP. Allowing your router to use both will enable to use the superior encryption when available.

The only situation where upgrading the encryption of your Wi-Fi network may pose a problem is with legacy devices. If you have devices manufactured before 2006 it’s possible that, without firmware upgrades or perhaps not at all, they will be unable to access any network but an open or WEP encrypted network. We’ve phased out such electronics or hooked them up to the hard LAN via Ethernet (we’re looking at you original Xbox).

The hassle factor for this modification is low and–unless you have a legacy Wi-Fi device you can’t live without–you won’t even notice the change.

Changing/Hiding Your SSID: Your router shipped with a default SSID; usually something simple like “Wireless” or the brand name like “Netgear”. There’s nothing wrong with leaving it set as the default. If you live in a densely populated area, however, it would make sense to change it to something different in order to distinguished it from the 8 “Linksys” SSIDs you see from your apartment. Don’t change it to anything that identifies you. Quite a few of our neighbors have unwisely changed their SSIDs to things like APT3A or 700ElmSt . A new SSID should make it easier for you to identify your router from the list and not easier for everyone in the neighborhood to do so.

Don’t bother hiding your SSID. Not only does it provide no boost in security but it makes your devices work harder and burn more battery life.  The short version is this: even if you “hide” your SSID it is still being broadcast and anyone using apps like inSSIDer or Kismet can see it.

The hassle factor for this modification is low. All you’ll need to do is change your SSID once (if at all) to increase recognition in a router-dense environment.


Filter Network Access by MAC Address:

Media Access Control addresses, or MAC address for short, is a unique ID assigned to every network interface you’ll encounter. Everything you can hook up to your network has one: your XBOX 360, laptop, smartphone, iPad, printers, even the Ethernet cards in your desktop computers. The MAC address for devices is printed on a label affixed to it and/or on the box and documentation that came with the device. For mobile devices you can usually find the MAC address within the menu system (on the iPad, for example, it’s under the Settings –> General –> About menu and on Android phones you’ll find it Settings –> About Phone –> Status menu).

One of the easiest ways to check the MAC addresses of your devices, besides simply reading the label on them, is to check out the MAC list on your router after you’ve upgraded your encryption and logged all your devices back in. If you’ve just changed your password you can be nearly certain the iPad you see attached to the Wi-Fi node is yours.

Once you have all the MAC addresses you can set up your router to filter based on them. Then it won’t be enough for a computer to be in range of the Wi-Fi node and have the password/break the encryption, the device intruding on the network will also need to have the MAC address of a device on your router’s whitelist.

Although MAC filtering is a solid way to increase your security it is possible for somebody to sniff your Wi-Fi traffic and then spoof the MAC address of their device to match one on your network. Using tools like Wireshark, Ettercap, and Nmap as well as the aforementioned BackTrack. Changing the MAC address on a computer is simple. In Linux it’s two commands at the command prompt, with a Mac it’s just about as easy, and under Windows you can use a simple app to swap it like Etherchange or MAC Shift.

The hassle factor for this modification is moderate-to-high. If you use the same devices on your network over and over with little change up then it’s a small hassle to set up the initial filter. If you frequently have guests coming and going that want to hop on your network it’s a hugehassle to always be logging into your router and adding their MAC addresses or temporarily turning off the MAC filtering.

One last note before we leave MAC addresses: if you’re particularly paranoid or you suspect someone is messing around with your network you can run applications like AirSnare and Kismet to set up alerts for MACs outside your white list.

Adjust the Output Power of Your Router: This trick is usually only available if you’ve upgraded the firmware to a third party version. Custom firmware allows you to dial up or down the output of your router. If you’re using your router in a one bedroom apartment you can easily dial the power way down and still get a signal everywhere in the apartment. Conversely if the nearest house is 1000 feet away, you can crank the power up to enjoy Wi-Fi out in your hammock.

The hassle factor for this modification is low; it’s a one time modification. If your router doesn’t support this kind of adjustment, don’t sweat it. Lowering the output power of your router is just a small step that makes it necessary for someone to be physically closer to your router to mess with it. With good encryption and the other tips we’ve shared, such a small tweak has a relatively small benefit.

Once you’ve upgraded your router password and upgraded your encryption (let alone done anything else on this list) you’ve done 90% more than nearly every Wi-Fi network owner out there.

Congratulations, you’ve hardened your network enough to make almost everyone else look like a better target! Have a tip, trick, or technique to share? Let’s hear about your Wi-Fi security methods in the comments.

What is a Customized SBC?

SBC – Single Board Computers

SBCs are off-the-shelf products that can be used to develop end-products or applications for a variety of industries. SBCs come along with integrated software and hardware, which includes SoC, memory, power requirements, real world multimedia and connectivity interfaces such as USB, UART, CAN, HDMI, Ethernet, SDIO, MMC, Analog Audio, display etc. The SBC approach helps system developers to focus on the application specific parts. An extensive range of SBCs based on a variety of microprocessors, memory sizes, supported interfaces and operating systems such as Windows Embedded Compact, Linux, Android etc. are available in the embedded market. This offers flexibility to the users to choose the appropriate SBC based on their cost, features and performance requirements. Low cost SBCs are widely used in academic research projects and in feature specific end-products.


However, the SBC approach suffers inherently from various drawbacks. First of all, the SBC approach leads to high switching cost to migrate to future technologies. As SBCs comes in standard sizes and real world interfaces, so it is difficult to accommodate future improvements in technology and thus the OEMs need to switch to an entirely new SBC solution. Secondly, customizing a SBC is cumbersome as the processor chipset and surrounding I/O are closely coupled due to the single-board design. Finally, space constrained applications may also struggle to use the standardized SBC available in the market.

The Computer On Module (COM) or System On Module (SOM) coupled along with a baseboard offers an equivalent solution as that of the SBCs. The COM approach separates the complex microprocessor part from the relatively simple I/O part and thus offers flexibility to customize the baseboard part based on the feature and size requirements of the end-product. Furthermore, pin-compatible modules ensure convenient and cost effective way to migrate to future technology.

A Customized SBC is an off-the-shelf embedded solution that is a combination of a COM/ SOM and a carrier board. This combination provides a desirable alternative to SBCs in developing any embedded end-products as the former offers the flexibility and scalability inherent to the COM approach and yet, is a ready-to-use complete embedded solution, one of the main benefits of the SBC approach.

Windows CE
Touch Support






What is a Computer-On-Module?

A Computer-On-Module (COM) / System On Module (SOM) is a highly integrated embedded computing solution that can be used to design and develop end-products for a variety of industries . The COM/SOM approach offers flexibility to system developers to focus on application development by using an off-the-shelf module that has the generic hardware and software to develop any application. This approach greatly reduces the time-to-market and development cost.

COM/SOM are generally built around microprocessors, system-on-chips, or microcontrollers. They integrate additional devices and peripherals which are needed to realise a fully functional computer, which normally includes RAM, non-volatile storage and power supplies.

They are essentially another layer of abstraction that sits above the SoC (System-on-Chip) concept, providing further integration in areas of hardware and software that are not application specific, but are application agnostic.

  • Optimized for Multicore
  • High-Speed Multimedia Interfaces (PCIe, SATA)
  • Direct Breakout™ for Easy Baseboard Routing
  • Fully Compatible Product Family
  • Small Form Factor
  • Free Support Directly from the Developers
  • 10+ Years Product Lifecycle

Carefully view the following image for the big picture 🙂

What is a Resistor?

Ads by Google Variable Resistor 5 Ohm Resistor Resistor High Voltage Resistor Component Electrical Resistor Series Resistor Resistor Values Standard Resistor Resistor Types Chip Resistors Resistor Calculator Resistor Color A resistor is an electronic component that can lower a circuit’s voltage and its flow of electrical current.
A resistor is an electronic component that can lower a circuit’s voltage and its flow of electrical current.

A resistor is a component of a circuit that resists the flow of electrical current. It has two terminals across which electricity must pass, and it is designed to drop the voltage of the current as it flows from one terminal to the other. Resistors are primarily used to create and maintain known safe currents within electrical components.

Resistance is measured in ohms, after Ohm’s law. This law states that electrical resistance is equal to the drop in voltage across the terminals of the resistor divided by the current being applied. A high ohm rating indicates a high resistance to current. This rating can be written in a number of different ways — for example, 81R represents 81 ohms, while 81K represents 81,000 ohms.

The amount of resistance offered by a resistor is determined by its physical construction. A carbon composition resistor has resistive carbon packed into a ceramic cylinder, while a carbon film resistor consists of a similar ceramic tube, but has conductive carbon film wrapped around the outside. Metal film or metal oxide resistors are made much the same way, but with metal instead of carbon. A wirewound resistor, made with metal wire wrapped around clay, plastic, orfiberglass tubing, offers resistance at higher power levels. Those used for applications that must withstand high temperatures are typically made of materials such as cermet, a ceramic-metal composite, or tantalum, a rare metal, so that they can endure the heat.

Electrical resistance was discovered by German physicist Georg Ohm in the 19th century and has since been measured in ohms
Electrical resistance was discovered by German physicist Georg Ohm in the 19th century and has since been measured in ohms


Resistors are coated with paint or enamel, or covered in molded plastic to protect them. Because they are often too small to be written on, a standardized color-coding system is used to identify them. The first three colors represent ohm value, and a fourth indicates the tolerance, or how close by percentage the resistor is to its ohm value. This is important for two reasons: the nature of its construction is imprecise, and if used above its maximum current, the value can change or the unit itself can burn up.

Every resistor falls into one of two categories: fixed or variable. A fixed resistor has a predetermined amount of resistance to current, while a variable one can be adjusted to give different levels of resistance. Variable resistors are also called potentiometers and are commonly used as volume controls on audio devices. A rheostat is a variable resistor made specifically for use with high currents. There are also metal-oxide varistors, which change their resistance in response to a rise in voltage; thermistors, which either raise or lower resistance when temperature rises or drops; and light-sensitive resistors.

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Source / Courtesy : WiseGeek

What Is a Capacitor?

Ben Franklin used a Leyden jar in his famous kite experiment.
Ben Franklin used a Leyden jar in his famous kite experiment.

A capacitor is a tool consisting of two conductive plates, each of which hosts an opposite charge. These plates are separated by a dielectric or other form of insulator, which helps them maintain an electric charge. There are several types of insulators used in capacitors, including ceramic, polyester, tantalum air, and polystyrene. Other common insulators include air, paper, and plastic. Each effectively prevents the plates from touching each other.

There are a number of different ways to use a capacitor, such as to store analog signals and digital data. Another type is used in the telecommunications equipment industry to adjust the frequency and tuning of telecommunications equipment. This is often referred to a variable capacitor. A capacitor is also ideal for storing electrons, but it cannot make them.


The first capacitor was the Leyden jar, invented at the Netherlands University in the 18th century. It consists of a glass jar coated with metal on the inside and outside. A rod is connected to the inner coat of metal, passed through the lid, and topped off with a metal ball. As with all capacitors, the jar contains an oppositely charged electrode and a plate that is separated by an insulator. The Leyden jar has been used to conduct experiments in electricity for hundreds of years.

A capacitor can be measured in voltage, which differs on each of the two interior plates. Both plates are charged, but the current flows in opposite directions. A capacitor contains 1.5 volts, which is the same voltage found in a common AA battery. As voltage is used, one of the two plates becomes filled with a steady flow of current. At the same time, the current flows away from the other plate.

To understand the flow of voltage in a capacitor, it is helpful to look at naturally occurring examples. Lightning, for example, works in a similar way. The cloud represents one of the plates and the ground represents the other. The lightning is the charging factor moving between the ground and the cloud.


Source / Courtesy : WiseGeek