Although the mouse is a handy tool, some people do not like using a mouse or have difficulty maneuvering one. For others, a mouse requires too much desktop space—a real problem when you are not working at a desk! For these reasons and others, hardware makers have developed devices that duplicate the mouse's functionality but interact with the user in different ways. The primary goals of these "mouse variants" are to provide case of use while taking up less space than a mouse. They all remain stationary and can even be built into the keyboard. Trackballs A trackball is a pointing device that works like an upside-down mouse. You rest your ...

What is Oersted's Law? Oersted's Law states that when a steady electric current passes through a wire it creates a magnetic field around it. Who developed Oersted's Law? Danish physicist Hans Christian Oersted (1777-1851), investigated and found the mathematical law which governs how strong the field was, which is now called Oersted's Law. When did Oersted began to investigate? In 1800, Alessandro Volta invented the voltaic pile, the first electrical battery. The following year, in 1801 Oersted began to investigate the nature of electricity and to conduct his first electrical experiments which resulted in Oersted's Law of electromagnetics. How did oersted discover electromagnetism? In 1820, while ...

A current-carrying conductor produces a magnetic field around it. i.e. behaves like a magnet and exerts a force when a magnet is placed in its magnetic field. Similarly, a magnet also exerts equal and opposite force on the current-carrying conductor. The direction of this force can be determined using Fleming's left-hand rule. Magnetic Force on a single Current-Carrying Conductor Electric current is an ordered movement of charge. Because charges ordinarily cannot escape a conductor, the magnetic force on charges moving in a conductor is transmitted to the conductor itself. A current-carrying wire in a magnetic field must, therefore, experience a force due ...

Although the keyboard and the mouse are the input devices that people use most often, there are many other ways to input data into a computer. Sometimes the tool is simply a matter of choice. Some users just prefer the feel of a trackball over a mouse. In many cases, however, an ordinary input device may not be the best choice. In a dusty factory or warehouse, for example, a standard keyboard or mouse can be damaged if it becomes clogged with dirt. Grocery checkout lines would slow down dramatically if cashiers had to manually input product codes and prices. In these environments, specialized input ...

Most input devices are designed to be used by hand. Even specialized devices like touch screens enable the user to interact with the system by using his or her fingertips. Unlike keyboards and mice, many of these input devices are highly intuitive and easy to use without special skills or training. The followings are different types of computer input devices designed to be used by hand: Pens Touch Screens Game Controllers ...

Circuit analysis is the process of finding all the currents and voltages in a network of connected components. We look at the basic elements used to build circuits, and find out what happens when elements are connected together into a circuit. This course deals with the fundamentals of electric circuits, their components and the mathematical tools used to represent and analyze electrical circuits. By the end of the course, the student must be able to confidently analyze and build simple electric circuits. ...

Applying mesh analysis to circuits containing current sources (dependent or independent) may appear complicated. But it is actually much easier than what we encountered in the previous section, because the presence of the current sources reduces the number of equations. Consider the following two possible cases. CASE 1 When a current source exists only in one mesh: Consider the circuit in [Fig. 1], for example. We set $i_2 = -5 A$ and write a mesh equation for the other mesh in the usual way, that is, $$-10 + 4i_1 + 6(i_1 - i_2) = 0$$ using $i_2=-5A$ in the above equation, $$ i_1 = -2 A$$ Fig. 2: ...

Since temperature can have such a pronounced effect on the resistance of a conductor, it is important that we have some method of determining the resistance at any temperature within operating limits. An equation for this purpose can be obtained by approximating the curve (in Fig. 1 ) by the straight dashed line that intersects the temperature scale at $-234.5℃$. Although the actual curve extends to absolute zero ($-273.15℃$, or $0 K$), the straight-line approximation is quite accurate for the normal operating temperature range. At two temperatures $T_1$ and $T_2$, the resistance of copper is $R_1$ and $R_2$, respectively, as indicated on the curve. Using a property of ...

Electrical Engineering and Telecommunications is arguably the origin of most high technology as we know it today. Based on fundamental principles from mathematics and physics, electrical engineering covers but not limited to the following fields:

• Power Engineering
• Electronic Engineering
• Computer Engineering
• Microelectronics
• Control System Engineering
• Signal Processing
• Telecommunication Engineering
• Instrumentation Engineering

...

Recalling the equation introduced for Ohm's law for electric circuits. $$ \text{Effect} = {\text{cause} \over \text{opposition}} $$ The same equation can be applied for magnetic circuits. For magnetic circuits, the effect desired is the flux $\Phi$. The cause is the magnetomotive force (mmf) , which is the external force (or "pressure") required to set up the magnetic flux lines within the magnetic material. The opposition to the setting up of the flux $\Phi$ is the reluctance $S$. Substituting, we have $$\bbox[10px,border:1px solid grey]{\Phi = {m.m.f \over S}} \tag{1}$$ The magnetomotive force is proportional to the product of the number of turns around the core ...

Georg Simon Ohm (1787-1854), a German physicist, in 1826 experimentally determined the most basic law relating voltage and current for a resistor. Ohm's work was initially denied by critics.
Born of humble beginnings in Erlangen, Bavaria, Ohm threw himself into electrical research. His efforts resulted in his famous law. He was awarded the Copley Medal in 1841 by the Royal Society of London. In 1849, he was given the Professor of Physics chair by the University of Munich. To honor him, the unit of resistance was named the ohm.

Andre-Marie Ampere was a French physicist and mathematician who was one of the founders of the science of classical electromagnetism. His name endures in everyday life in the ampere, the unit for measuring electric current.
On September 18, 1820, introduced a new field of study, electrodynamics, devoted to the effect of electricity in motion, including the interaction between currents in adjoining conductors and the interplay of the surrounding magnetic fields. Constructed the first solenoid and demonstrated how it could behave like a magnet (the first electromagnet). Suggested the name galvanometer for an instrument designed to measure current levels.

Count Alessandro Volta was a Italian scientist who contributed in the development of an electrical energy source from chemical action in 1800.
For the first time, electrical energy was available on a continuous basis and could be used for practical purposes. He also developed the first condenser known today as the capacitor. He has invited to Paris to demonstrate the voltaic cell to Napoleon. The International Electrical Congress meeting in Paris in 1881 honored his efforts by choosing the volt as the unit of measure for electromotive force.

Leon Charles Thevenin was a French telegraph engineer who worked on Ohm's law and extended it to the analysis of complicated electrical networks. He is remembered today almost entirely for one small piece of work. His theorem, published in 1883, was based on his study of Kirchhoff's Laws and is found in every basic textbook on electrical circuits. It has made his name familiar to every student of electrical circuits and to every electrical and electronics engineer.

English scientist, physicist and chemist Michael Faraday is known for his many experiments that contributed greatly to the understanding of electromagnetism. Faraday, who became one of the greatest scientists of the 19th century, began his career as a chemist. His major contribution, however, was in the field of electricity and magnetism . He was the first to produce an electric current from a magnetic field, invented the first electric motor and dynamo.