Confessions Of An Energy Waster

Electricity is the most important form of energy available today. It is used to run practically all equipment in homes and offices. It is surprising yet true that even when we think, we are not consuming electricity we are still consuming it. The "stand by mode" is a big time culprit.

Do I Waste Electric Energy?

Electrical energy is a precious resource and anyone with even a basic understanding of the processes of power generation and distribution will know that it is certainly a fact. Still most of us do not realize the importance of energy conservation. Find out how people waste energy and the best methods of reducing this message by reading this article dealing with the confessions of an energy waster.

Confessions of an Energy Waster

If I’m asked the question, am I an energy waster, my answer in the first go would be a very firm, "No, I do not. I make sure to switch off the lights, the fan, and the air conditioner when I move out of a room. I am an environmentally conscious person and am concerned about global warming."

However, on introspection I would have second thoughts. Let me ask a few more questions of myself to find out the truth:

Do I leave the television or the set-top box in stand by mode?

Well yes, I do leave both the above on stand by mode. In addition to the above I also leave my laptop and the radio on the stand by mode. This is because it is so convenient for me, I don’t have to wait for the device to warm up and start. It saves so much of my time.

Do I leave plugs in sockets even when the device is not in use and switches in the "on" mode?

Once again, yes, I do leave the plugs in the socket and I leave the socket switch on. My mobile phone charger stays plugged in even when I’m not charging my mobile. My electric tooth brush also remains plugged in. The switch on the board may be on, but I’m not using the device.

Do I need to ask myself further questions? I don’t think so. I should accept the fact that I am an energy waster and my previous claim stands refuted.

Let us look at some facts and try to understand why the answers to the above questions make me an energy waster.

Stand by Mode

The stand by mode is that state of an electronic device where it is between fully off and fully on. The device according to us is switched off, but in reality, it is not. It consumes energy to maintain itself on the stand by mode. It can be said that the device is in a state where it is ready to be switched on; it is waiting for a command from the remote control. To continuously search for the remote, it consumes power. T.V. sets, computer systems, cordless telephones are some of the devices which have the standby mode. To actually switch it off, the plug should be removed from the socket. In the stand by mode, it wastes energy.

The problem with the standby mode is not that the devices consume too much electricity, the problem is that there are too many devices that are consuming electricity on the standby mode. As per reports of the IEA (International Energy Association) in a typical European, Japanese, Australian and North American home, an average of twenty devices are continuously on in stand by mode. As per the same reports “Standby power is responsible for 5-10% of total electricity use in most homes and an unknown amount in commercial buildings and factories. Standby power is responsible for roughly 1% of global carbon dioxide emissions.”

This energy is also referred to by several other names such as vampire power, parasitic power, leaking electricity, and so on

Switches in the "On" Mode

I have already confessed that I leave the switches on. My argument to assert that I am not an energy waster is that there is no device that is plugged in, as a result no energy is being consumed. Agreed, but the reason why I am wrong here is very simple to understand. When do some devices, like lights, toasters, and electric heaters, draw energy? When the switch is put "On." Until I put the switch on, it does not draw energy.

What can I Do?

Now, that I have understood the problem and where I am going wrong, let us concentrate on the solutions. What I need to do is just to change a few habits and be a little less careless to begin with. Just some small actions can make stop wasting energy:

    * Avoid leaving electronic devices on the stand by mode. Unplug them or use a power switch to disable them.

    * Don't leave lights, heaters, and other electrical appliances on when not being used.

Do this, and soon you will be saying, "Yes, I contribute towards reducing electrical consumption and global warming, just by being a smart consumer and controlling my use of stand by power and parasitic loads in the home and by not powering lights and appliances unless I want to immediately use them"

Introduction

                     Introduction

Advancement of inverter technique has made available the ac power supply, whose output voltage and current can be controlled as vector quantities of variable amplitude and frequency. Controllability of ac motors are now invading into application areas where dc motor control have been predominantly used. However it seems that ac motor control technique has not been well grounded on a sound theoretical base. The problem is that transient phenomena of ac motors have not been well analyzed. The conventional ac motor theories have not been well analyzed.                          The conventional ac motor theories have been lacking in their ability to analyze electromagnetic transient phenomena of ac motors. Most control theories of ac motors have been based on the equivalent two phase machine theory, which is sometimes called d,q axes theory. Its characteristic equation is of 4^th degree and thus the theory is unwieldy. It is being tried to replace the two phase theory with the space vector method. But it relies too much on physical pictures and is not mathematically rigorous in derivation of circuit equations of ac motors. The spiral vector method will simplify analysis of electro magnetic transient phenomena ac circuits and ac machines, just as the phasor notation simplified analysis of steady states of ac circuits and machines. Analytical results obtained by the spiral vector have revealed superior control features of ac motors. The spiral vector method will also bring about a new development in the ac circuit theory, where steady state and transient state are separately treated by the separately treated by the separate two theories, the ac circuit which uses the phasor notation, and the transient theory, which uses instantaneous real values. The spiral vector will unify the two theories into the spiral vector theory of ac circuit and machine.          

                           In industry application the variable speed drive use often a vector control of induction machine. The field orientation defines conditions for decoupling the field from the toque control the field oriented induction motor emulates separately exited DC motor in two aspects

·         Both the magnetic field and the torque developed in the motor can be controlled independently

·         Optimal conditions for torque production, resulting in the maximum torque per Unit samplers, occur in the motor both in steady state conditions and transient   Conditions of an operation.

A vector control is obtained by the conventional theories which are based on two axis method, they involve complicated variable transformations, which are not so successful in analyzing the machine. In this work we propose a vector control of induction machine by a spiral vector theory. The application of this theory conduct to eliminate the Park’s Transformation to make the regulation and to obtain a good decoupling between the air gap flux and electromagnetic torque

VECTOR CONTROL OF INDUCTION MOTOR BY A

                         CONTENTS

 Introduction

1.Traditional nine level inverter

2.Cascaded  31-level inverter with high power quality

3.Experimental setup

4.Switching pattern

5.Harmonic analysis

6.Simulation of  31-level inverter

Algorithm flowchart

“c” program

simulation results           

7.Experimental verification

8.Conclusions

           

List  Of  Symbols

 : Leakage inductance of phase a

 : Resistance of phase a

 :  Leakage inductance of phase r

R₂  :   Resistence of phase r

M_rs :   Maximum value of mutual inductance between stator and rotor windings

q  :    w_mt

P  :    pair pole number

J   :    Total constant mechanical inertia

f_r   :    Total friction coefficient s

T_r  :     Resistance torque

W_r  :     Mechanical speed

T_em :     Electromagnetic torque(N.m)

j₀   :    Air-gap flux(Wb)

j_0ref  :   Air-gap flux of reference(Wb)

T_emref  :  Electromagnetic torque of reference(N.m)

                        ABSTRACT

AC motors, whilst being very economical, rugged and reliable due to the absence of commutators and brushes, have inherently poor dynamic behavior. However, the dynamic behavior can be made to match that of an equivalent separately excited DC motor using Field Orientated or Vector Control.In this project vector control of induction machine by a spiral vector theory is proposed. This method permits to establish the performance equations of the induction machine in function only one phase variables of the stator and rotor.   The obtained equations are basically using in field oriented control. The   simulation results give a good decoupling between the air gap flux and electromagnetic torque and it sufficient to track one voltage quantities   or current to make the regulation in the case of a direct vector control of induction machine.

Make a 100 Watt Transistor Amplifier Circuit…

Whether it’s for your cell phone or your iPod, this transistor amplifier circuit will convert any tiny audio into an ear pounding 100 watts of raw music power. A complete 100w transistor power amplifier schematic is provided here.

Introduction

If we compare the simplicity of the proposed 100w transistor power amplifier schematic design to its power output, which is a good 100 watts, indeed it looks very impressive.

The entire circuit utilizes commonly available components and may be simply built over a general purpose board. If all the connections are done accurately as shown in the diagram, the circuit should immediately start “pumping” your loud speakers with a high quality music output. I have personally tested this circuit and believe me its response is outstanding, build a couple of them and it becomes compatible with stereo inputs- that also means now you are producing 200 watts of brain-pounding music power.

Let’s examine the circuit functioning.

Circuit Description

At the first glance the circuit rather appears to be unsymmetrical in design, due to an unbalanced looking output stage. However a closer look will prove this wrong. Transistors T9, T10, T11 and T12, T13, and T14 form two well-balanced halves of the circuit, perfectly complementing each other.

The input stage employs the standard R/C filter configuration. R1 and R2 fix the input impedance, and the inclusion of C1 creates a high-pass filter that blocks all frequencies around 1.5 Hz. C1 also functions as an input stage DC bias isolator.

The presence of R2 and C2 ensures no frequency above 250 KHz makes its way into the circuit, thus blocking most of the high frequency RF intrusions.

Transistor T1 and T2 are wired up in a standard differential amplifier mode.

The remaining portion of the circuit is mainly the output stage and is responsible for amplifying the differential stage into the loud speakers.

Specifications:

Power output is 60 watts into 8 Ω and 100 watts into 4 Ω loudspeaker.

Total harmonic distortion is less than 0.01 %.

Frequency range is within 20 Hz and 20 kHz.

The input sensitivity is in the vicinity of 750 mV.

The frequency characteristics lie in between 1 dB from 15 Hz to around 100 kHz.

Due to its very high amplification factor of around 20,000, the output stage may have an ideally low quiescent current drain of about 40 mA.

The quiescent current can be set through P1 with a digital multimeter connected across resistors R6 and R7.

Adjust P1 until the meter reads about 40 mV, corresponding to 50 mA current.

Important Technical Parameters to be Followed

Although the circuit parameters are not critical and may be built over a general purpose board, care should be taken that the component layout does not differ from the circuit diagram by much.

Preferably use separate heatsinks for the transistors T10, T11, T13, T14, to avoid the involvement of messy mica isolators, heatsink paste, etc.

The output stage of the circuit is virtually unaffected by temperature variations, however ideally T8, T9 and T7, T12 may be coupled with each other (by gluing them together) to enhance thermal stability of the circuit.

The output inductor L1 is made by winding 20 turns of 0.8 mm super enameled copper wire right over the resistor R24.

The current consumption may shuffle in between 1 and 3 Amp depending on the volume level of the unit.

Parts List

You will require the following parts to build this 100w transistor power amplifier schematic design.

All resistors are 1/4w, CFR unless otherwise specified.

R1 = 470K,

R2 = 47K,

R3 = 330E,

R4, R5 = 10K,

R6, R7, R20, R21, R22, R23, R24 = 1E/2W,

R8, R17 = 56E,

R9 = 100K,

R10, R11, R12, R13 = 4K7,

R14, R15 = 10K,

R16, R19 = 100E,

R25 = 10E/2W,

P1 = 100E Preset,

C1 = 1µ/25V,

C2 = 1n, CERAMIC,

C3, C4 = 100Pf

C5 = 100n,

C6, C7 = 1000uF/35V,

L1 = see text,

D1, D2 = RED LED 5mm,

Rest of the diodes are = 1N4148,

T1 = Pair of well-matched BC546,

T2 = Pair of well-matched BC556,

T3 = BC557,

T4, T7, T8 = BC547,

T5, T12 = BC556,

T6, T9 = BC546,

T10 = BD140 (Mount over "C" channel heatsink)

T13 = BD139 (Mount over "C" channel heatsink)

T11, T14 = 2N3055 (Mount over large finned-type heatsink)

General Purpose Board,

Power Supply = 25-0-25V, 5 Amp.

Fuse, Mains Cord, Metallic Enclosure, Switch, External Sockets etc....

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...