Free Essays on HNC

Report As part of my HNC I was asked to Design, Manufacture and Test a circuit that would control both traffic lights and motor situated on a model of the Kincardine Bridge. The specification I was given was that the circuit board could be no bigger than 100 x 160mm and could cost no more than  £50. Taking the specification into account I searched for components I would use to construct the circuit making sure the price was under the  £50 limit (the total cost was  £42.99). The second task I undertook was to design a board within the required size (the final size was 89 x 74mm) but I ran into problems with the design because of this there was a total of 20 designs before the board was ready to be manufactured, some of the problems are listed below. SIL Reed relay pins were the wrong size Earth connections were missing LED’s were over-lapping The pins on the 7406 were connected the wrong way round Once the PCB was designed, the board was then manufactured. The manufacturing process can be found in Appendix page 2`. The next stage was to test and populate the board, continuity testing was done by using a multi-meter to check for open and short circuits and then hand soldering all the components in place. The population process took me around 3 hours instead of the 2 hours planned as I had to de-solder my wire links as they were not of an acceptable standard. The final process was to test the finished PCB, this was done by testing the outputs on the board as they all worked first time I had no extra fault finding/debugging to do. Conclusion As the circuit worked first time I proved that I would be capable of undergoing projects like this in the future. The main reason for the circuit working was the amount of time I spent at the design process. This would save companies money in real life, as there would be no waste of materials. I also feel that my project skills are improving, as there is a big difference bet... Free Essays on HNC Free Essays on HNC Report As part of my HNC I was asked to Design, Manufacture and Test a circuit that would control both traffic lights and motor situated on a model of the Kincardine Bridge. The specification I was given was that the circuit board could be no bigger than 100 x 160mm and could cost no more than  £50. Taking the specification into account I searched for components I would use to construct the circuit making sure the price was under the  £50 limit (the total cost was  £42.99). The second task I undertook was to design a board within the required size (the final size was 89 x 74mm) but I ran into problems with the design because of this there was a total of 20 designs before the board was ready to be manufactured, some of the problems are listed below. SIL Reed relay pins were the wrong size Earth connections were missing LED’s were over-lapping The pins on the 7406 were connected the wrong way round Once the PCB was designed, the board was then manufactured. The manufacturing process can be found in Appendix page 2`. The next stage was to test and populate the board, continuity testing was done by using a multi-meter to check for open and short circuits and then hand soldering all the components in place. The population process took me around 3 hours instead of the 2 hours planned as I had to de-solder my wire links as they were not of an acceptable standard. The final process was to test the finished PCB, this was done by testing the outputs on the board as they all worked first time I had no extra fault finding/debugging to do. Conclusion As the circuit worked first time I proved that I would be capable of undergoing projects like this in the future. The main reason for the circuit working was the amount of time I spent at the design process. This would save companies money in real life, as there would be no waste of materials. I also feel that my project skills are improving, as there is a big difference bet...

10 Calcium Element Facts You Should Know

10 Calcium Element Facts You Should Know Calcium is one of the elements you need in order to live, so its worth knowing a little bit about it. Here are some quick facts about the element calcium. Fast Facts: Calcium Element Name: CalciumElement Symbol: CaAtomic Number: 20Standard Atomic Weight: 40.078Discovered By: Sir Humphry DavyClassification: Alkaline Earth MetalState of Matter: Solid Metal Calcium is element atomic number 20 on the periodic table, which means each atom of calcium has 20 protons. It has the periodic table symbol Ca and an atomic weight of 40.078. Calcium isnt found free in nature, but it can be purified into a soft silvery-white alkaline earth metal. Because the alkaline earth metals are reactive, pure calcium typically appears dull white or gray from the oxidation layer that quickly forms on the metal when its exposed to air or water.  The pure metal can be cut using a steel knife.Calcium is the 5th most abundant element in the Earths crust, present at a level of about 3% in the oceans and soil. The only metals more abundant in the crust are iron and aluminum. Calcium is also abundant on the Moon. It is present at about 70 parts per million by weight in the solar system.  Natural calcium is a mixture of six isotopes, with the most abundant (97%) being calcium-40.The element is essential for animal and plant nutrition. Calcium participates in many b iochemical reactions, including building skeletal systems, cell signaling, and moderating muscle action.  It is the most abundant metal in the human body, found mainly in bones and teeth. If you could extract all of the calcium from the average adult person, youd have about 2 pounds (1 kilogram) of the metal.  Calcium in the form of calcium carbonate is used by snails and shellfish to construct shells. Dairy products and grains are the primary sources of dietary calcium, accounting or about three-quarters of dietary intake. Other sources of calcium include protein-rich foods, vegetables, and fruits.Vitamin D is essential for calcium absorption by the human body. Vitamin D is converted to a hormone which causes intestinal proteins responsible for calcium absorption to be produced.Calcium supplementation is controversial. While calcium and its compounds are not considered to be toxic, ingesting too many calcium carbonate dietary supplements or antacids can cause milk-alkali syndrome, which is associated with hypercalcemia sometimes leading to fatal renal failure. Excessive consumption would be on the order of 10 g calcium carbonate/day, though symptoms have been reported upon ingesting as little as 2.5 g calcium carbonate daily.  Excessive calcium consumption has been linked to kidney stone formation and artery calcification.Calcium is used for making cement, making cheese, removin g nonmetallic impurities from alloys, and as a reduction agent in the preparation of other metals.  The Romans used to heat limestone, which is calcium carbonate, to make calcium oxide. The calcium oxide was mixed with water to make cement, which was mixed with stones to build aqueducts, amphitheaters, and other structures that survive to the present day. Pure calcium metal reacts vigorously and sometimes violently with water and acids.  The reaction is exothermic. Touching calcium metal can cause irritation or even chemical burns. Swallowing calcium metal can be fatal.The element name calcium comes from the Latin word calcis or calx  meaning lime.  In addition to occurrence in lime (calcium carbonate), calcium is found in the minerals gypsum (calcium sulfate) and fluorite (calcium fluoride).Calcium has been known since the 1st century, when the ancient Romans were known to make lime from calcium oxide.  Natural calcium compounds are readily available in the form of calcium carbonate deposits, limestone, chalk, marble, dolomite, gypsum, fluorite, and apatite.Though calcium has been known for thousands of years, it was not purified as an element until 1808 by Sir Humphry Davy (England). Thus, Davy is considered to be the discoverer of calcium. Sources Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 112.Parish, R. V. (1977).  The Metallic Elements. London: Longman. p.  34.Weast, Robert (1984).  CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp.  E110.​