Friday, January 24, 2020
Simple Voltage and Current Measurement :: essays research papers
Experiment I Simple Voltage and Current Measurement Objective The objective of this experiment was to measure the Voltage and Current. Upon completion of this experiment I was able to: 1)     Set the DC power supply to a specific voltage. 2)     Properly connect the voltmeter to measure voltage. 3)     Measure current with the ammeter. 4)     Measure resistance with the ohmmeter. 5)     Determine the accuracy of a given meter reading. Theory The theory required for this experiment was an understanding of Ohm’s Law. Ohm’s Law is the algebraic relationship between voltage and current for a resistor. Resistance is the capacity of materials to impede the flow of current or electric charge. Ohm’s Law expresses the voltage as a function of the current. It was also necessary that the concept of measurement accuracy be understood. This is discussed below. Accuracy is of primary importance in an experimental work. The tolerance quoted by the meter manufacturer allows us to calculate the accuracy of any reading taken with that particular meter. For example, assume that the dc voltage scale on a particular multimeter is rated at  ± 3% of full scale. This means that a reading on the 10V scale is accurate to ( ± 0.03%)(10) =  ± 0.3V. Thus, a reading of 9V on the10V scale indicates a true voltage, which lies between 8.7 and 9.3 V. A reading of 1V on the scale would indicate a true voltage between 0.7 and 1.3 V. At this point, the error is  ± 30%! Any reading less than 10% of full scale should be viewed with suspicion since most meters are very inaccurate n this range. Circuit Diagrams For this experiment we used a Power supply source, voltmeter/ammeter/ohmmeter. Fig 1.1 Power Supply and voltmeter in parallel Power Supply                    Voltmeter - Fig 1.2 Simple voltage measurement circuit. a                              a b               a          b                    a a d                          c                                   c                              d c                         d      Fig 1.3 Simple current measurement circuit Power Supply (Be sure current                                              I control is at maximum setting)           Fig 1.4 Circuit to measure resistance                               Procedure To measure the voltage output of the power supply, we connected the voltmeter as shown in Fig. 1.1. We made sure that the voltmeter is always connected in parallel with the voltage being measured. Before turning on the power, we set the voltmeter voltage range to a DC value higher than the highest voltage we expected to measure. This precaution must be observed with all meters in order to avoid the possibility of burning out an expensive instrument. We then set the current control to maximum current and adjust the output voltage of the supply to values of 2.5, 10, and 15.
Thursday, January 16, 2020
Homer’s Ideal of Excellence
Throughout this excerpt of â€Å"The Iliad†by the great poet Homer, shows the ideals way back into their era. In this epic segregated values of both men and women are seen in Homer’s era. This epic story begins with the young prince of Troy, Paris, who kidnaps Helen, wife of the king of the Greek state of Sparta. After this treachery towards Sparta the Spartan kings Brother, Agamemnon, attacked Troy. The excerpt begins with Paris’s brother, Hector, another prince of Troy, is talking to his wife, Andromache, just before he goes to fight Achilles. Achilles is a great warrior which has slain many foes with nothing but a scratch including all of Andromache all seven brothers who he fought all at once. Andromache attempts to plead to Hector to flee, but his honor and courage strives him to continue to his impending doom. These words spoken by both Hector and Andromache seem as though they both knew it was most likely was going to be their last words. The way Homer writes the tone of these last words between husband and wife were so compelling in the fact that a mans honor and bravery were way more important than staying alive and taking care of his new born son and wife. From just reading this part of Homer’s writing it is obvious how it shaped the minds of all of Greece and set values among the people of the era. After reading this part of the poem understanding it comes to light by fully seeing how the honor of a man in this era is more important than anything even including your own family. This can be seen When Homer writes; â€Å"†All that, my dear,†said the great Hector of the glittering helmet, â€Å"is surely my concern. But if I hid myself like a coward and refused to fight, I could never face the Trojans and the Trojans ladies in their trailing gowns†. Also Homer goes on to illustrate that he must because that is how Hector was raised and how he must uphold his families honor in the name of his deceased father. Another thing that can be seen is very important to the people of this era was their need to make their gods happy, which in Greek culture was Zeus. The last words of Hector before he goes to fight the unstoppable soldier, Achilles, was praying to the great Greek gods, but not for himself, instead for his son to be just as strong and brave as himself and to be a mighty king of Ilium. He then continues to pray to make his son an even better man then himself. This brought upon another ideal in mind, the linage of your family. As in back then when you were born you automatically obtained all of you bloodlines successes and failures and were marked by them. At the end of the excerpt Hector says to his wife to not be worried about him and not to be distressed but instead continue on her duties at home, where she should continue looming and using the spindles. He then goes on to say how war has no business with women and how it is the business of every man and especially himself since he is the prince of Troy. This emphasizes how the duties were segregated among the Greek people. How women are condemned to taking care of the children, cleaning, and looming cloths whereas men were condemned to death in war for their rulers. These poems did not record history yet the Greek people took these stories as authentic history causing a past in which they can look upon when seeking guidance on what they should do in the Greek culture and ideals. Also they gave the Greek people with a cast of heroes like Hector and Achilles to be their role model. These poems brought both men and women a guide of what they should do to pursue arete (or excellence) among their society. Whether it was inside the household or out on the battlefields both men and women by the Homeric world were taught to pursue excellence (or arete). The â€Å"Iliad†and the â€Å"Odysseus†shaped the ideals of the Greeks and gave a model for the rest of Greek culture to follow.
Wednesday, January 8, 2020
Learn About the Many Varieties of Quartz
Quartz is an old German word that originally meant something like hard or tough. It is the most common mineral in the continental crust, and the one with the simplest chemical formula: silicon dioxide or SiO2. Quartz is so common in crustal rocks that its more notable when quartz is missing than when its present. How to Identify Quartz Quartz comes in many colors and shapes. Once you start studying minerals, though, quartz becomes easy to tell at a glance. You can recognize it by these identifiers: A glassy lusterHardness 7 on the Mohs scale, scratching ordinary glass and all types of steelIt breaks into curved shards rather than flat-faced cleavage fragments, meaning it exhibits conchoidal fracture.Almost always clear or whiteAlmost always present in light-colored rocks and in sandstonesIf found in crystals, quartz always has a hexagonal cross-section like that of a common pencil. Most examples of quartz are clear, frosted, or found as milky-white grains of small size that dont display crystal faces. Clear quartz may appear dark if its in a rock with a lot of dark minerals. Special Quartz Varieties The pretty crystals and vivid colors youll see in jewelry and in rock shops are scarce. Here are some of those precious varieties: Clear, colorless quartz is called rock crystal.Translucent white quartz is called milky quartz.Milky pink quartz is called rose quartz. Its color is thought to be due to various impurities (titanium, iron, manganese) or microscopic inclusions of other minerals.Purple quartz is called amethyst. Its color is due to holes of missing electrons in the crystal in combination with iron impurities.Yellow quartz is called citrine. Its color is due to iron impurities.Green quartz is called praseolite. Iron impurities account for its color, too.Gray quartz is called smoky quartz. Its color is due to holes of missing electrons in combination with aluminum impurities.Brown smoky quartz is called cairngorm and black smoky quartz is called morion.The Herkimer diamond is a form of natural quartz crystal with two pointed ends. Quartz also occurs in a microcrystalline form called chalcedony. Together, both minerals are also referred to as silica. Where Quartz Is Found Quartz is perhaps the most common mineral on our planet. In fact, one test of a meteorite (if you think youve found one) is to be sure it doesnt have any quartz. Quartz is found in most geologic settings, but it most typically forms sedimentary rocks like sandstone. This is no surprise when you consider that nearly all the sand on Earth is made almost exclusively from grains of quartz. Under mild heat and pressure conditions, geodes can form in sedimentary rocks that are lined with crusts of quartz crystals deposited from underground fluids. In igneous rocks, quartz is the defining mineral of granite. When granitic rocks crystallize deep underground, quartz is generally the last mineral to form and usually has no room to form crystals. But in pegmatites quartz can sometimes form very large crystals, as long as a meter. Crystals also occur in veins associated with hydrothermal (super-heated water) activity in the shallow crust. In metamorphic rocks such as gneiss, quartz becomes concentrated in bands and veins. In this setting, its grains do not take their typical crystal form. Sandstone, too, turns into a massive quartz rock called quartzite. Geological Significance of Quartz Among the common minerals, quartz is the toughest and most inert. It makes up the backbone of good soil, providing mechanical strength and holding open pore space between its grains. Its superior hardness and resistance to dissolution are what make sandstone and granite endure. Thus you could say that quartz holds up the mountains. Prospectors are always alert to veins of quartz because these are signs of hydrothermal activity and the possibility of ore deposits. To the geologist, the amount of silica in a rock is a basic and important bit of geochemical knowledge. Quartz is a ready sign of high silica, for example in rhyolite lava. Quartz is hard, stable, and low in density. When found in abundance, quartz always points to a continental rock because the tectonic processes that have built the Earths continents favor quartz. As it moves through the tectonic cycle of erosion, deposition, subduction, and magmatism, quartz lingers in the uppermost crust and always comes out on top.
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