Voltage, Current, Resistance and Ohm's Law

Monday, 21 October 2013

Voltage, Current, Resistance and Ohm's Law

When electrons are separated from atoms – either through friction (eg, static electricity), chemical reaction (eg, a battery), electromagnetism or other phenomenon – an electrical field is formed, consisting of two oppositely charged terminals, and an associated “tension” or “pressure” between them.

The measure of this “tension” or “pressure” is known as voltage.

Atomic Structure

Atomic Structure.....
The atom is a basic unit of matter, consisting of a central nucleus (containing positively charged protons and electrically neutral neutrons), and surrounded by negatively charged electrons which move in 1 or more orbital “shells” around the nucleus.
For example, consider a carbon atom:

The number of protons in a nucleus is the atomic number, and defines the type of element the atom forms. Thus, carbon has an atomic number of 6.The number of neutrons in a nucleus determines the isotope of an element. For example, carbon-12 has 6 protons and 6 neutrons, while carbon-14 has 6 protons and 8 neutrons.
Most matter is said to be electrically “neutral”, since the #electrons = #protons. (Ions are atoms which are not neutral – ie, they have either gained or lost electrons).
An atom may have multiple electron “orbital shells”. In the case of carbon, the first shell contains 2 electrons, and the second shell contains 4 electrons.

A group of atoms may remain “bound” to each other, forming a molecule.

Binary Addition

The process for adding binary numbers is the same in any number system, except that you must be aware of when (and what) to “carry”.
In the decimal system, a carry occurs when the sum of 2 digits is 10 or more. For example,

The Binary Number System.......

The Binary Number System..

The binary number system is a special code that the computer uses for representing numeric data. Numeric data is any value that can be used for mathematical operations such as addition and subtraction. This code is completely different than the ASCII system, except that only 1s and 0s are used.
For example, consider the code 01001010. In the ASCII system, this represents the letter “J”. However, in the binary number system, this represents the number 74.

ASCII and Unicode.............

ASCII - American Standard Code for Information Interchange
About the same time that IBM was developing EBCDIC, a group of engineers from the American Standards Association were developing another code for representing character data. The result was ASCII - the American Standard Code for Information Interchange.
ASCII used 7 bits to represent characters, giving 128 possible symbols.
Here is the original ASCII table from 1963. Like EBCDIC, the grey areas represent non-printable control keys (Esc, Del, Backspace, etc.), as well as special characters used in data transmission.

To find the ASCII code for a particular character,

Locate the character in the table (for example, "J")
Write down the three "Low Order" bits on the left side of the table directly across from the character (for "J", they are 100).
Write down the four "High Order" bits at the top of the table, directly above the character (for "J", they are 1010).

BCD and EBCDIC

BCD and EBCDIC
BCD - Binary Coded Decimal
Early mainframe computers in the 1950s were programmed using numeric codes, not text. As a result, the first coding system used in these computers only needed to represent the ten digits in our number system. The BCD (Binary Coded Decimal) system used 4 bits to represent numbers as follows:

Therefore, to represent the number 253, the computer would store 0010 0101 0011.

Digital vs. Binary Data

Digital vs. Binary Data....
Humans use numbers that contain only ten different digits – 0 thru 9. The Latin prefix for ten is “dec”, hence, our number system is known as decimal.
Numeric values inside any electronic device are stored using only 2 distinct values – 1 and 0. The Latin prefix for two is “bi”, hence, the number system used inside electronic devices is known as binary).
For example,

Digital vs. Analog

Digital vs. Analog

Modern electronic devices - computers, video game consoles, cell phones, iPods, etc. - all store data in digital format.

Digital data gets its name from the fact that almost any type of data in an electronic device - characters, images, video and sound - can be broken down into smaller parts and given numeric (or "digital") values.
For example,

The Second Generation: 1956 to 1963...

Processing
Transistors were invented in 1947 as an alternative to vacuum tubes for use as electronic switches. At first they were more expensive (transistor = $8 vs. vacuum tube = 75¢). However, by the mid 1950s they had decreased significantly in price and size, and began to see widespread use in radios, televisions - and computers.
The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation predecessors. Although the transistor still generated a great deal of heat and still required massive amounts of wiring, it was a vast improvement over the vacuum tube.

One of the most successful second generation computers was the IBM 1401, which was introduced in 1959. By 1964, IBM had installed more than one hundred thousand units (which could be rented for $2,500 / month), capturing about one third of the world market.

Researchers at the University of Southern California’s ICT Graphics Lab have created a new type of holographic display that can generate simultaneous 3D views for multiple observers without the need for special glasses.

Battery History

Batteries have been around longer than you may think. In 1938, archaeologist Wilhelm Konig discovered some peculiar clay pots while digging at Khujut Rabu, just outside of present-day Baghdad, Iraq. The jars, which measure approximately 5 inches (12.7 centimeters) long, contained an iron rod encased in copper and dated from about 200 B.C.

Not Nokia : Its Newkia who is going to Launch Android Mobiles soon..

Not Nokia : Its Newkia who is going to Launch Android Mobiles soon:
One of the most intriguing question
that Bloggers, CEO’s, Webmasters
keep asking to each other that when
Nokia is going to launch android
smartphones. Everyone is eagerly
waiting for Nokia to make phones
with Android as their OS.

Sunday, 20 October 2013

Email in your eye? Next-generation video screen glasses could lay messages or GPS over your field of vision..

Translucent TV: Lumus' PD-18-2 is a set of spectacles that can beam high-quality images directly into your eyes but allows the user to see through the images too

As advances in computer technology make gadgets ever smaller and more portable the idea of carrying a screen of any kind could soon be outdated.

Consumer products with screens have dropped in size from computer to laptop to tablet via phone.

The demo applications Microsoft has shown so far for its Surface touch-tabletop system --for ordering drinks, sharing photos by dragging them and finger painting -- have left me cold.

But at the Consumer Electronics Show this week, Microsoft is discussing and demonstrating some different Surface application prototypes that seem somewhat more compelling.

During his CES keynote, Microsoft Chairman Bill Gates showed off a snowboard-customization demo that indicates the kinds of interactive retail applications which might shine on Surface multi-touch systems. Microsoft issued some talking points about the demo, claiming it "provides a clear solution to common consumer pain points," including (according to Microsoft):

being overwhelmed by choices
not having enough information
can’t make it yours
want to share it with friends

"The (Surface snowboard) application showcases the four key attributes of a surface computer including; multi-touch, object recognition, direct interaction and multi-user," said an e-mail message sent to me by the Surface team.

Microsoft also is highlighting at this week's CES show a "wine-bar demo application." This app looks similar to the drink and food ordering application Microsoft has been showing off for the past few months during public Surface demos. But there's one new element I hadn't seen before that is more educational. Tags on customers' wine glasses, when placed on the Surface tabletop, call up a map of the region from which the wine originates. The touch-activated map can provide all kinds of additional details about the vinters, the grapes, the climate, etc. For those who listened closely to Gates' Sunday night keynote, there was a hint that gaming and office-productivity applications are in the pipeline for a Surface "desk," "meeting room table" or other kinds of future Surface systems, as well. From the transcript of Gates' remarks:
Gates and others at Microsoft are still betting big on natural user interfaces -- touch, speech, gestures -- as being the keys to the input kingdom. Supposedly, these input modes were going to take off during the "first digital decade." But Tablet PCs didn't take hold at anywhere near the rates he predicted.
While touch and speech will no doubt take off on cell phones and on-board auto systems, I admit I'm still am a doubter about how quickly or well they'll be adopted by PC users. Call me a Luddite, but if the Surface had a keyboard, I'd definitely prefer it over touch or speech.
What's your take on the Surface? Will touch technology drive the Surface? Or will Surface finally get more Microsoft users to make use of non-keyboard-based input technologies?
abut Microsoft