Electrical Engineering

Electrical engineering mainly deals with the generation and distribution of power and maintenance of large power systems. It has been known in the past to encompass electronic engineering, which has obtained an identity of its own only in the recent years. In most cases, both of these disciplines are offered through a combined course of study.
History of Electrical Engineering

Electrical engineers are responsible mainly for power generation and power transmission. The importance of electrical engineering was recognized only in the 19th century. Some of the main contributors to the field of electrical engineering were George Ohm, Micheal Faraday, James Clark Maxwell, Thomas Elva Edison and Nikola Tesla. However, there were many people who played their own part in bringing electrical engineering to the level it is at today.

Applications of Electrical Engineering
The main aim is to ensure the safe usage of electricity. For this purpose they are given the responsibility of designing electrical appliances as well as the wiring system of electricity to ensure supply of electricity to these appliances. Many times electrical engineers have to work on projects that involve a certain degree of electronics engineering. Electrical engineers are concerned with designing the flight systems of aircrafts and rocket propulsion systems. Industrial automation and automobile control system design are also a part of electrical engineering.

We can see that the process of manufacturing has become extremely streamlined in the recent years. In the earlier days, workers where used to perform each and every task. This lead to greater manufacturing time, and output also suffered in quality at times. However, since the process of automation has been implemented to many manufacturing plants, the efficiency of manufacturing has increased rapidly. The dependence on human work force has decreased, with time wastage reduced and quality of output increased.

Role of Electrical Engineering
Electrical engineering has an important role to play in many other fields of study. For instance, signal processing makes use of the principles of electrical engineering in modifying the digital and analog nature of the signals to obtain the required output. Telecommunications is another area that benefits from electrical engineering. It deals with the transmission of information through different channels to enable communication. Instrumentation engineering has developed as a field of study where devices are used to take reading of pressure, temperature, current, etc. in the electrical equipment.

In today’s world, all branches of engineering have a specific role to play. This means electrical engineering is important for the development of all other branches of engineering too.

Modern developments

During the development of radio, many scientists and inventors contributed to radio technology and electronics. In his classic UHF experiments of 1888, Heinrich Hertz transmitted (via a spark-gap transmitter) and detected radio waves using electrical equipment. In 1895, Nikola Tesla was able to detect signals from the transmissions of his New York lab at West Point (a distance of 80.4 km / 49.95 miles). In 1897, Karl Ferdinand Braun introduced the cathode ray tube as part of an oscilloscope, a crucial enabling technology for electronic television. John Fleming invented the first radio tube, the diode, in 1904. Two years later, Robert von Lieben and Lee De Forest independently developed the amplifier tube, called the triode. In 1895, Guglielmo Marconi furthered the art of hertzian wireless methods. Early on, he sent wireless signals over a distance of one and a half miles. In December 1901, he sent wireless waves that were not affected by the curvature of the Earth. Marconi later transmitted the wireless signals across the Atlantic between Poldhu, Cornwall, and St. John's, Newfoundland, a distance of 2,100 miles (3,400 km). In 1920 Albert Hull developed the magnetron which would eventually lead to the development of the microwave oven in 1946 by Percy Spencer.In 1934 the British military began to make strides toward radar (which also uses the magnetron) under the direction of Dr Wimperis, culminating in the operation of the first radar station at Bawdsey in August 1936.

In 1941 Konrad Zuse presented the Z3, the world's first fully functional and programmable computer. In 1946 the ENIAC (Electronic Numerical Integrator and Computer) of John Presper Eckert and John Mauchly followed, beginning the computing era. The arithmetic performance of these machines allowed engineers to develop completely new technologies and achieve new objectives, including the Apollo missions and the NASA moon landing.

The invention of the transistor in 1947 by William B. Shockley, John Bardeen and Walter Brattain opened the door for more compact devices and led to the development of the integrated circuit in 1958 by Jack Kilby and independently in 1959 by Robert Noyce.Starting in 1968, Ted Hoff and a team at Intel invented the first commercial microprocessor, which presaged the personal computer. The Intel 4004 was a 4-bit processor released in 1971, but in 1973 the Intel 8080, an 8-bit processor, made the first personal computer, the Altair 8800, possible.,...

Electrical engineering History

Electricity has been a subject of scientific interest since at least the early 17th century. The first electrical engineer was probably William Gilbert who designed the versorium: a device that detected the presence of statically charged objects. He was also the first to draw a clear distinction between magnetism and static electricity and is credited with establishing the term electricity. In 1775 Alessandro Volta's scientific experimentations devised the electrophorus, a device that produced a static electric charge, and by 1800 Volta developed the voltaic pile, a forerunner of the electric battery.

However, it was not until the 19th century that research into the subject started to intensify. Notable developments in this century include the work of Georg Ohm, who in 1827 quantified the relationship between the electric current and potential difference in a conductor, Michael Faraday, the discoverer of electromagnetic induction in 1831, and James Clerk Maxwell, who in 1873 published a unified theory of electricity and magnetism in his treatise Electricity and Magnetism.
Thomas Edison built the world's first large-scale electrical supply network.

During these years, the study of electricity was largely considered to be a subfield of physics. It was not until the late 19th century that universities started to offer degrees in electrical engineering. The Darmstadt University of Technology founded the first chair and the first faculty of electrical engineering worldwide in 1882. In the same year, under Professor Charles Cross, the Massachusetts Institute of Technology began offering the first option of Electrical Engineering within a physics department. In 1883 Darmstadt University of Technology and Cornell University introduced the world's first courses of study in electrical engineering, and in 1885 the University College London founded the first chair of electrical engineering in the United Kingdom. The University of Missouri subsequently established the first department of electrical engineering in the United States in 1886.
Nikola Tesla made long-distance electrical transmission networks possible.

During this period, the work concerning electrical engineering increased dramatically. In 1882, Edison switched on the world's first large-scale electrical supply network that provided 110 volts direct current to fifty-nine customers in lower Manhattan. In 1884 Sir Charles Parsons invented the steam turbine which today generates about 80 percent of the electric power in the world using a variety of heat sources. In 1887, Nikola Tesla filed a number of patents related to a competing form of power distribution known as alternating current. In the following years a bitter rivalry between Tesla and Edison, known as the "War of Currents", took place over the preferred method of distribution. AC eventually replaced DC for generation and power distribution, enormously extending the range and improving the safety and efficiency of power distribution.

The efforts of the two did much to further electrical engineering—Tesla's work on induction motors and polyphase systems influenced the field for years to come, while Edison's work on telegraphy and his development of the stock ticker proved lucrative for his company, which ultimately became General Electric. However, by the end of the 19th century, other key figures in the progress of electrical engineering were beginning to emerge......

Electrical engineering

Electrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics and electromagnetism. The field first became an identifiable occupation in the late nineteenth century after commercialization of the electric telegraph and electrical power supply. It now covers a range of subtopics including power, electronics, control systems, signal processing and telecommunications.

Electrical engineering may include electronic engineering. Where a distinction is made, usually outside of the United States, electrical engineering is considered to deal with the problems associated with large-scale electrical systems such as power transmission and motor control, whereas electronic engineering deals with the study of small-scale electronic systems including computers and integrated circuits. Alternatively, electrical engineers are usually concerned with using electricity to transmit energy, while electronic engineers are concerned with using electricity to transmit information. More recently, the distinction has become blurred by the growth of power electronics.....

JK and T Flip-Flops

JK Flip-Flop

In the previous article we discussed about RS and D flip-flops. In this article lets discuss about the other two types of flip-flops, starting with JK flip flop and its diagram.

A JK flip-flop has two inputs similar to that of RS flip-flop. We can say JK flip-flop is a refinement of RS flip-flop. JK means Jack Kilby, a Texas instrument engineer who invented IC. The two inputs of JK Flip-flop is J (set) and K (reset). A JK flip-flop is nothing but a RS flip-flop along with two AND gates which are augmented to it.

The flip-flop is constructed in such a way that the output Q is ANDed with K and CP. Such an arrangement is made so that the flip-flop is cleared during a clock pulse only if Q was previously 1. Similarly Q’ is ANDed with J and CP, so that the flip-flop is cleared during a clock pulse only if Q’ was previously 1.

JK Flip-Flop

When J=K=0

When both J and K are 0, the clock pulse has no effect on the output and the output of flip-flop is same as its previous value. This is because when both the J and K are 0, the output of their respective AND gate becomes 0.

When J=0, K=1

When J=0, the output of the AND gate corresponding to J becomes 0(i.e.) S=0 and R=1. Therefore Q’ becomes 0. This condition will reset the flip-flop. This represents the RESET state of Flip-flop.

When J=1, K=0

In this case, the AND gate corresponding to K becomes 0(i.e.) S=1 and R=0. Therefore Q becomes 0. This condition will set the Flip-flop. This represents the SET state of Flip-flop.

When J=K=1

Consider the condition when CP=1 and J=K=1. This condition will cause the output to complement again and again. This complement operation continues until the Clock pulse goes back to 0. Since this condition is undesirable, we have to find a way to eliminate this condition. This undesirable behaviour can be eliminated by Edge triggering of JK flip-flop or by using master slave JK Flip-flops.

The characteristic table explains the various inputs and the states of JK flip-flop.

T Flip-Flop

T flip-flops are similar to JK flip-flops. T flip-flops are single input version of JK flip-flops. This modified form of JK flip-flop is obtained by connecting both inputs J and K together. This flip-flop has only one input along with Clock pulse. These flip-flops are called T flip-flops because of their ability to complement its state (i.e.) Toggle. So they are called as Toggle flip-flop.

When T=1 and CP=1, the flip-flop complements its output, regardless of the present state of the Flip-flop. In this case the next state is the complement of the present state.

When T=0, there is no change in the state of the flip-flop (i.e.) the next state is same as the present state of the flip-flop. From the characteristic table and characteristic equation it is quite evident that when T=0, the next sate is same as the present state...