Electronics can best be described as the branch of applied physics concerning the generation, control and amplification of electric currents and voltages by influencing the movement of electrons in a vacuum (vacuum tubes) or in semiconducting materials (transistors and diodes). Pure semiconductor materials such as silicon have a rather high resistance to the flow of electric current.
When an impurity such as phosphorus or arsenic (which are referred to as donor atoms since they donate a free electron to the crystal) is added, it causes the semiconductor material to have many extra and loosely held electrons. If impurities such as boron or gallium are added (which are referred to as acceptor atoms since they can accept an additional electron) to the semiconductor material, it creates a shortage of electrons. When N and P type semiconductor materials are joined together such as in a diode, an unusual but very important phenomenon occurs at the junction where the two materials are joined. This movement of free electrons and holes creates a narrow negative charge zone on the P side of the junction and a narrow positive charge zone on the N side.
This potential voltage cannot be measured directly with a voltmeter since the net charge across the entire PN device is zero. If a battery is connected to a diode, with the negative terminal connected to the cathode of the diode and the positive terminal connected to the anode, current will flow easily and the diode will appear to have a very low resistance – like a conductor. If the positive terminal of a battery is connected to the N type material or cathode of the diode (the banded end) and the negative battery terminal is connected to the P type material or anode of the diode, the junction acts like a very high resistance and only a very small amount of electrical current is able to flow.
This reverse bias causes free electrons in the N-type material to move toward the positive charge on the cathode of the diode. If the reverse voltage across the diode is allowed to increase past the peak inverse voltage (PIV) rating of the diode, the reverse current will increase rapidly and may destroy the diode.
A semiconductor PN junction (diode) as designed has a very large resistance to current flow in one direction and a very low resistance to current flow in the other direction.
These PN junctions form the basis for the semiconductor components that ultimately control the many different electronic devices we use today. It is the miniaturization of these PN junctions over time that has led to a revolution in sophisticated hand held electronics that are smaller, lighter, less power hungry and lower in cost than just a short time ago. Another basic fact about electricity is the attraction and repulsion that exists between electrons and protons and is primarily due to the charge associated with each particle. A fundamental law of electricity is that like charges will repel one another and opposite charges will attract one another. In the years 1785 and 1786 a French physicist named Charles Coulomb described in precise mathematical terms how these positive and negative charges repel and attract each other.
The ease in which electrons can move in a substance is determined by how tightly held or how free the electrons are in the outer orbits of its atoms. Certain materials such as glass, mica and most plastics have their electrons and protons closely associated with each other in a manner that inhibits the movement of electrons through that substance.
Voltage is the electrical pressure that drives electric current through a circuit and is measured in volts.
If two equally and oppositely charged objects are connected by a metallic conductor such as a wire, the charges will neutralize each other.
In an electric circuit, there is a continuous movement of electrons from negative to positive.
There are three interdependent quantities that affect the flow of electricity in a circuit. The first is the potential difference in the circuit referred to as electromotive force (emf) or voltage.
When an electrical current flows through a conductor, two important effects can be observed. Around the year 1808, a French physicist by the name of Andre Marie Ampere discovered that one electrical wire can produce a magnetic effect upon another electrical wire next to it. In 1830, Joseph Henry in America and, a year later, Michael Faraday in London discovered that a magnetic field could indeed induce a current – provided the magnetic field was kept in motion. Electromagnetic induction occurs when a conductor is moved through the lines of force in a magnetic field.
Electromagnetic waves are radiations that require no material medium for propagation and travel in the form of a transverse wave at the speed of light in a vacuum. The theory of electromagnetic waves originated with the Scottish physicist James Clerk Maxwell.
Maxwell’s theory of electromagnetic waves indicated that the wave motion was not of a material substance, but of oscillations of both electric and magnetic fields of the same frequency and in phase with each other and also at right angles to each other and to the direction of propagation. Maxwell had showed that a pulsating electric current would create a pulsating magnetic field in the space around it, and that this magnetic field would create another electric field and so on in a self propagating manner. Maxwell did not directly dismiss the concept of ether, however, his theory made it clear that such a medium for the transmission of electromagnetic waves was not necessary. When a conductor is moved back and forth in a magnetic field, the flow of current will change directions as often as the motion of the conductor changes direction. The most important reason for the use of alternating current is that the voltage of the current can be easily changed to almost any value by the means of a simple electromagnetic device called a transformer. When an alternating current is passed through a coil of wire, the magnetic field that surrounds the coil expands and collapses and then expands in a field of opposite polarity and then again collapses. If the second coil has a greater number of turns than the first, the voltage induced in the second coil will be greater than the first because the magnetic field is acting upon a greater number of individual conductors. This transformer action is what allows the transmission of electrical power over long distances. No discussion of alternating current or our modern power grid would be complete without mentioning Nikola Tesla. Tesla is also well known for his experiments with high voltage, high frequency electricity. Tesla will always be recognized as one of the outstanding pioneers in the field of electric power. Over the years Tesla received numerous awards including honorary doctoral degrees from Columbia University and Yale University.
Gold along with Silver and Copper are excellent conductors of both electricity and heat because of the single outer electron that is mostly lost to the atom and is free to move around the metal.
NASA's Solar Dynamics Observatory is on a mission to study the Sun in unprecedented detail.
The LUX (Large Underground Xenon) experiment is a 370 kg liquid xenon time-projection chamber that aims to directly detect galactic dark matter in an underground laboratory 1 mile under the earth, in the Black Hills of South Dakota, USA.
Determine how much water is in Jupiter's atmosphere, which helps determine which planet formation theory is correct. A closeup view of a solar eruption shooting out into space as seen by NASA's STEREO-B on March 12, 2012. STEREO (Solar TErrestrial RElations Observatory) is the third mission in NASA's Solar Terrestrial Probes program (STP). Advanced Composition Explorer (ACE) observes particles of solar, interstellar, interplanetary, and galactic origins, spanning the energy range from solar wind ions to galactic cosmic ray nuclei. THEMIS is a mission to investigate what causes auroras in the Earth's atmosphere to dramatically change from slowly shimmering waves of light to wildly shifting streaks of color. NASA's Earth Observing System is a series of polar-orbiting satellites designed for long term global observations of the land surface, biosphere, solid Earth, atmosphere and oceans.
Providing insight into our planet's global hydrologic cycle, Aqua is part of NASA's EOS series of satellites. AURA is another EOS satellite that will be used to gather data on the dynamics of the Earth's upper and lower atmosphere and its underlying chemistry. NASA's Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) spacecraft is designed to study the role that clouds and aerosols play in regulating Earth's weather, climate and air quality.
NASA's CLOUDSAT satellite, in conjunction with CALIPSO, will be used to study the role that clouds and aerosols play in regulating Earth's weather, climate and air quality.
NASA's TERRA satellite is considered the flagship mission in NASA's Earth Observing System. The Kepler Mission is specifically designed to survey our region of the Milky Way galaxy in order to locate Earth-size and smaller planets in or near the habitable zone of its parent star and also to determine the fraction of the hundreds of billions of stars in our galaxy that might have such planets. Mars Odyssey is an orbiter carrying science experiments designed to make global observations of Mars to improve our understanding of the planet's climate and geologic history, including the search for water and evidence of life-sustaining environments.
The Mars Atmosphere and Volatile EvolutioN or MAVEN mission will orbit Mars to explore how the sun may have stripped Mars of most of its atmosphere, turning a planet once possibly habitable to microbial life into a cold and barren desert world. New Horizons is a mission designed to fly by Pluto and its moon Charon and transmit images and data back to Earth. The Deep Space Climate Observatory, or DSCOVR, will maintain the nation's real-time solar wind monitoring capabilities which are critical to the accuracy and lead time of NOAA's space weather alerts and forecasts. Without timely and accurate warnings, space weather events like the geomagnetic storms caused by changes in solar wind have the potential to disrupt nearly every major public infrastructure system, including power grids, telecommunications, aviation and GPS.

In this photo, captured by the AQUA satellite, the Barents Sea north of Norway is awash in colorful swirls of blue and green in July of 2003. The colors can be produced by a variety of pigments, including chlorophyll, that the plants use to harness sunlight for photosynthesis.
In July 2012, a massive ice island broke free of the Petermann Glacier in northwestern Greenland. On July 21, 2012, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this image of the iceberg's continuing journey.
This Mars surface image was taken by the Thermal Emission Imaging System (THEMIS) on board the Mars Odyssey spacecraft. The information contained herein is not designed or authorized for use in any type of medical, life saving or life sustaining applications. Anyone using this information do so entirely at their own risk and agree to indemnify Saros Electronics and its agents for any damages resulting from its use. These materials acquire special characteristics that are created by alterations in their crystal structure.
When impurities are added (a process called “doping”) to the pure semiconductor material (the amounts and types of these impurities are carefully controlled) the material will have a much lower resistance to electric current. In an unbiased condition, free electrons from the N-type material drift across the junction into the P-type material.
This narrow positive and negative charge region is called the junction barrier or the depletion zone and exhibits a potential voltage difference that must be overcome in order for current to flow through the junction. However, this potential can be measured as a voltage drop across the diode when the diode has a voltage applied to it in a circuit with a load.
The battery voltage must be greater than the junction barrier voltage, approximately 0.7 volts for a silicon diode. Current flow through the diode is due to free electrons in the N-type material being attracted to the positive charge of the battery.
In a similar manner, holes in the P-type material move toward the negative charge on the anode.
There is special class of diodes called zener diodes that are designed to be used in this breakdown voltage region – provided there is some in circuit resistance to prevent excessive current flow. The amount of leakage current depends on the material the diode is constructed of and also the temperature. This is what makes semiconductor materials different from ordinary conductors or insulators. This includes two layer components such as diodes, three layer components such as bipolar transistors and even four layer components like silicon controlled rectifiers and triacs. The charge on the electron is called a negative charge and the charge associated with the proton is called a positive charge. Certain substances such as amber will become negatively charged when rubbed with a piece of woolen cloth. Coulomb’s law reveals that attraction and repulsion weaken very rapidly with distance and increase just as rapidly as the charged particles get closer together. A higher number of volts means more electrical pressure and a lower number of volts means less electrical pressure. This occurs when the electrons move through the conductor from the negatively charged object to the positively charged object. If this electron movement is in one direction only, the flow is referred to as direct current (dc). In the year 1807, a Dane named Hans Christian Oersted began a series of experiments involving electricity.
When an electrical current flows through two nearby parallel conductors, the conductors will be attracted to each other if the current is flowing in the same direction and will repel one another if the current flow is in opposite directions.
The magnetic field will act on the free electrons in the conductor, displacing them and creating a potential difference and a flow of current in the conductor. Therefore, electromagnetic induction will occur when either the conductor is moved in a stationary magnetic field or a magnetic field is moved near a stationary conductor.
Such waves consist of oscillating electric and magnetic fields of force that are of widely varying frequencies. In a series of papers published in the 1860’s, he analyzed mathematically the theory of electromagnetic fields and was correct when he predicted that visible light was an electromagnetic phenomenon. However, physicists had originally assumed that the waves were mechanical in nature and required some form of medium for propagation, similar to sound waves which require air or another medium in order to propagate.
This chain of electric and magnetic disturbances would flow across space until it contacted another piece of matter where it would generate an electric current similar to the one that started the process. The concept of ether was eventually discarded with the release of Einstein’s Special Theory of Relativity. This is the basic idea behind the electrical generator which powers our modern electrical grid.
If another conductor or coil is placed in the magnetic field of the first, but not in direct connection with it, the movement of the magnetic field induces an alternating current in the second coil. Conversely, if the number of turns in the second coil is less than the primary, the induced voltage in the secondary will be lower than in the primary. By transmitting electricity at higher voltages, say at 200,000 volts instead of 2000 volts, the resistance of the transmission lines will have a smaller effect on the amount of power delivered to the load.
Born in July of 1856 in Smiljan, Austria – Hungary, Tesla was a brilliant electrical engineer and inventor. In 1899 Tesla built a giant coil (well known today as a “Tesla Coil”) in Colorado Springs, Colorado that could transmit electrical energy for miles without the use of wires. He was also active in many other scientific areas as well with over 700 patents registered worldwide. The state of New York and other states as well proclaim July 10, his birthday, as Nikola Tesla Day. Onboard telescopes will scrutinize sunspots and solar flares using more pixels and colors than any other observatory in the history of solar physics. Look deep into Jupiter's atmosphere to measure composition, temperature, cloud motions and other properties. The orange image is of extreme ultraviolet light, while the part of the image in green is from a different STEREO telescope showing visible light beyond the edge of the solar disk.
The mission, launched in October 2006, has provided a unique and revolutionary view of the Sun-Earth System.
The process that triggers substorms occurs deep within the Earth's magnetosphere, the region of space surrounding the Earth that is dominated by the Earth's magnetic field. AQUA will collect data on global precipitation, evaporation, and the cycling of water as it observes our Earth's oceans, atmosphere, land, ice, snow cover and vegetation. Aura will study trace gasses in the atmosphere so we can better understand global climate change, global warming, the global movement of polluted air, and ozone depletion in the stratosphere. Calipso's instruments will provide statistics on the geographic and vertical distribution of aerosols around the globe and also monitor subvisible clouds in the upper troposphere and polar stratospheric clouds.
CLOUDSAT's primary instrument is a 94 GHz cloud profiling radar that will be used to provide estimates of the percentage of Earth's clouds that produce rain.
TERRA carries five instruments that observe Earth's atmosphere, ocean, land, snow, ice, and energy budget.
Kepler finds planets by looking for tiny dips in the brightness of a star when a planet crosses in front of or transits the star. One of the chief scientific goals that 2001 Mars Odyssey will focus on is mapping the chemical elements and minerals that make up the Martian surface. MAVEN will be the first spacecraft mission dedicated to exploring the upper atmosphere of Mars. It will then continue on into the Kuiper Belt where it will fly by one or more Kuiper Belt Objects and return further data. This spectacular display of color reveals the biological richness of these cold, nutrient rich waters with a bloom of tiny marine plants called phytoplankton. The brightest blue color is sometimes the result of a kind of phytoplankton called a coccolithophore that has a calcium carbonate (chalk) covering.
On July 16, the giant iceberg could be seen drifting down the fjord, away from the floating ice tongue from which it calved. An interval equal to 6585.32 days, after which the eclipses in the cycle repeat with the path in longitude shifted 120 degrees farther west. They were impressed by the beauty of the structural order that they were discovering, and regarded mathematics as sacred knowledge.Pythagoras (c.

Doping elements such as arsenic and phosphorus are called pentavalent elements because their atoms have five electrons in their outer orbits.
Holes in the P-type material drift across the junction and combine with free electrons in the N-type material. Any increase in the applied forward voltage will result in a corresponding increase in the amount of current flow. This movement of electrons and holes expands the depletion zone and the junction barrier voltage increases to equal the external applied voltage. An increase in operating temperature will result in a corresponding increase in leakage current. Integrated circuits can contain millions of transistors made from PN junctions that are grown on a single silicon substrate. Atoms in their normal state are electrically neutral with the number of electrons equaling the number of protons. The electrons, freed from its parent atom and set into motion is electricity. Other materials, mostly metals, permit the movement of electrons and are known as conductors. If the flow alternates in either direction, the movement is referred to as alternating current (ac).
One ampere is equal to 6,280,000,000,000,000,000 electrons per second past any point in the circuit.
This is the result of electrons moving from a higher potential to a lower potential, giving up heat in the process. He reasoned that if electric current was allowed to flow through a wire, it should turn the wire into a kind of magnet with the property of north and south poles. Some of the frequency bands generally recognized are known as radio waves, infrared radiation, visible light, ultraviolet radiation, x-rays and gamma rays. Since experiments indicated that light could move easily through a vacuum, the nature of this medium or “ether” as it was called had to be extremely diffuse, present even in the best laboratory vacuum. He was educated at the Polytechnic School in Graz, Austria and also at the University of Prague. One area that he was a leading pioneer in was the basic system for radio transmission: describing the elements of a radio transmitter and also constructing a device that could receive radio waves. Tesla’s numerous discoveries are the basis for many of the electrical devices we take for granted today and these devices will continue to be with us far into the future.
While Silver has the highest electrical conductivity of any of the metals, Gold has the advantage of greater corrosion resistance.
Detecting its interactions with normal matter, and studying its properties, is one the most challenging problems in modern day physics. The two nearly identical observatories - one ahead of Earth in its orbit, the other trailing behind - have traced the flow of energy and matter from the Sun to Earth. When reporting space weather, ACE can provide an advance warning (about one hour) of geomagnetic storms that can overload power grids, disrupt communications on Earth, and present a hazard to astronauts. At substorm orbit, stretched magnetic field lines snap back to a configuration similar to that of a bar magnet, energizing charged particles and dumping them into the Earth's upper atmosphere, where they produce shimmering aurora that can be seen at high latitudes in both the northern and southern hemisphere.
The radar will also provide vertically-resolved estimates of how much water and ice are in Earth's clouds and estimate how efficiently the atmosphere produces rain from condensates. TERRA observations will reveal humanity's impact on the planet and provide crucial data about natural hazards like fire and volcanoes. Odyssey also served as a communication relay for landers such as the Mars Exploration Rovers Spirit and Opportunity. The primary objectives are to characterize the global geology and morphology and map the surface composition of Pluto and Charon and characterize the atmosphere of Pluto and its escape rate. This chalky covering is bright white, and mixes with the blue reflection off the water to produce brilliant hues. The area in the crystal where there is a vacancy caused by the absence of an electron is called a “Hole”. Also, the increased number of electrons in the area near the junction has the effect of reducing the size of the depletion zone. If there are more than the normal number of electrons, the atom will have a negative charge. Since most atoms except hydrogen have more than one proton, you might wonder why the nucleus of an atom remains together since the protons would be affected by the positive charges of the other nearby protons.
In one of his experiments, he placed a wire with current flowing in it parallel with a compass needle. All the components present in the electromagnetic spectrum regardless of frequency have in common the typical properties of wave motion including interference and diffraction. After working for several years as an electrical engineer for a telephone company, he immigrated in 1884 to the United States, where he later became a naturalized citizen. This was about the time the difference in opinion over Edison’s use of direct current and the advantages in the use of alternating current began. The system consisted of a polyphase electrical generator, a set of step-up and step-down transformers and a polyphase electric motor. Explore and study Jupiter's magnetosphere near the planet's poles, especially the auroras – Jupiter's northern and southern lights –providing new insights about how the planet's enormous magnetic force field affects its atmosphere. STEREO has revealed the 3D structure of coronal mass ejections; violent eruptions of matter from the sun that can disrupt satellites and power grids, and help us understand why they happen. Discovering what causes auroras to change will provide scientists with important details on how the magnetosphere works and the important Sun-Earth connection. They studied the recurring, harmonious patterns inherent in mathematics, music and nature, and they recognized that such patterns occurred throughout the universe. It is important to note that in normal operation, there is some resistance elsewhere in the circuit that the diode is part of in order to prevent excessive current flow.
The reason is the strong nuclear force (one of the four basic forces in nature) which keeps the protons and neutrons in the atoms nucleus together. Under ordinary conditions conductors will offer some opposition to the flow of electrical current and this resistance will limit current flow. He discovered that the compass needle moved, swinging around a quarter of a turn until it was positioned precisely at right angles to the wire. Each number held a place in the cosmic story of transformation, the universal creating process, as such:The number one represented unity, the original state of the universe and the first stage in the process of becoming. With this accomplishment, an alternating current power grid was soon destined to become the world standard for electrical power distribution. Our mind divides the world into dualities—heaven and earth, day and night, light and dark, right and left, man and woman, you and I. The down-side of dividing the world into polarities, however, is that it separates us from nature, wholeness, others and being.
Polar tension is at the root of all birth and creation, but it also creates one of our largest dilemmas’; what is beyond polarities?To the Greek philosophers then, one and two were not considered to actually be numbers. They surmised that creation is involved when a pair of distinct but equal opposites unites to produce a third, new, thing.
Modern scientists know this as the laws of attraction and repulsion as from the basic polarity, light, energy and all matter results.The number three is the “Triad”.
Three was considered by the ancients to be the first-born of the parent numbers, one and two.
It supersedes the eternal solitude of one and the polarity of two and represents an entirely new synthesis. In these themes of three, opposites are balanced by a third, mediating element that reconciles a conflict or enables the journey.Even we Engineers turn to 3 for the foundation of creativity. As a structure, the triangle and its three-dimensional brother, the pyramid, are the structurally strongest shapes. The discovery and incorporation of the arch into ancient architecture resulted from a realization of this strength. Unlike any other shape, the three sides of a triangle resolve opposite tensions into one solid, stable whole needing no outside support. In an arch, the top point of the triangle is the keystone that diverts weight downward through its opposite sides into the earth.

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