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Summary of direct current generators

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SUMMARY This chapter introduced you to the basic principles concerning direct current generators. The different types of dc generators and their characteristics were covered. The following information provides a summary of the major subjects of the chapter for your review. MAGNETIC INDUCTION takes place when a conductor is moved in a magnetic field in such a way that it cuts flux lines, and a voltage (emf) is induced in the conductor. THE LEFT-HAND RULE FOR GENERATORS states that when the thumb, forefinger, and middle finger of the left hand are extended at right angles to each other so that the thumb indicates the direction of movement of the conductor in the magnetic field, and the forefinger points in the direction of the flux lines (north to south), the middle finger shows the direction of induced emf in the conductor. AN ELEMENTARY GENERATOR consists of a single coil rotated in a magnetic field. It produces an ac voltage. A BASI...
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Microelectronics: Introduction, Evolution Of Microelectronics And vacuum-Tube Equipment.

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MICROELECTRONICS LEARNING OBJECTIVES Learning objectives are stated at the beginning of each topic. These learning objectives serve as a preview of the information you are expected to learn in the topic. The comprehensive check questions are based on the objectives. By successfully completing the OCC-ECC, you indicate that you have met the objectives and have learned the information. The learning objectives are listed below. Upon completion of this topic, you will be able to: 1. Outline the progress made in the history of microelectronics. 2. Describe the evolution of microelectronics from point-to-point wiring through high element density state-of-the-art microelectronics. 3. List the advantages and disadvantages of point-to-point wiring and high element density state-of- the-art microelectronics. 4. Identify printed circuit boards, diodes, transistors, and the various types of integrated circuits. Describe the fabrication techniques of these components. 5. Define th...
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Defects of vision and their correction

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The main features of the human eye     This image is a simplified diagram of the human eye.      In many respects it is similar to the camera . An image is formed by the eye lens on the sensitive retina at the back of the eye, whence a message is transmitted to the brain by way of the optic nerve . The iris the colored membranous disk,with a pupil in the center. It has two types of muscular fibers: circular and radial . In the bright light   the circular fibers contract and the radial fibers relax : the pupil becomes less in size to reduce the amount of light that enters. in the less light the circular muscles relax, and the radial ones contract. The pupil then becomes wider so that more light will enter to facilitate vision. in other words, the colored portion of the eye automatically adjusts the size of the pupil or circular opening in its center according to the intensity of the light falling on it. Focusing of the image...
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