Operational Amplifier (Op-Amp) Lab Report Example | Topics and Well Written Essays - 2000 words

Operational Amplifier (Op-Amp) - Lab Report Example ed, high gain, voltage amplifier. They form the basis of a wide array of electronic circuits, including amplifiers, buffers, comparators, and analogue-digital/digital-analogue converters. An op-amp is represented in schematic notation by the following symbol: Figure 1 - Circuit Diagram Element Where V+ and V- are the differential inputs, VS+ and VS-, are the positive and negative supply voltages, and Vout is the output of the amplifier. While they are represented as a single element, op-amps are in fact composed of many circuit elements, and are conventionally sold as monolithically integrated silicon chips. 1.1 Origins and Development of the Operational Amplifier The operational amplifier can trace its origins back to fledgling telecommunications industry in the United States at the turn of the 19th century. With the invention of the telephone, there was demand to carry electronic voice communications over longer and longer distances. The challenge was to build signal repeating equi pment that minimized problems like distortion and crosstalk, so that multi-channel communications could be carried from one side of the country to the other. Advances in electronic equipment and amplifier design eventually led to the development of the first operational amplifiers at Bell Labs in the 1940s. Vacuum tube devices were essential to the development of amplifier technology, because they made possible for the first time the non-linear manipulation of voltage and current. â€Å"The Fleming Diode†, patented in 1904 by J.A. Fleming [1], was the first major breakthrough in this respect because it allowed for the rectification of current. Then in 1906, Lee De Forest [2] built upon this work with â€Å"The Audion†, a three-element triode vacuum tube that was the first device capable of signal amplification. Amplifiers built in the following years suffered from stability problems, as they used a positive feedback principle, and distortion due to the generation of ha rmonics by vacuum tubes. Harold Black [3], in 1927 while searching for a means of improving linearity and stability of currently-used positive feedback amplifiers, came up with the negative feedback amplifier principle. The idea of deliberately sacrificing gain in to improve stability ran counter to conventional ideas at the time, and it took 9 years for the original patent application to be accepted. Once implemented, however, the advantages of this approach quickly became clear. Within a few years the theory for stable amplifier design was formalized by Nyquist and Bode, two names now synonymous with fundamental electrical engineering principles, during their work at Bell Labs. At this

P. H. Delamotte Photograph of the Interior of the Crystal Palace Essay

P. H. Delamotte Photograph of the Interior of the Crystal Palace After a successful year of housing the Great Exposition, the Crystal Palace by Joseph Paxton was disassembled and moved to Sydenham, where it stood for the next 85 years (Hobhouse, 32). The Palace, built for the 1851 World's Fair in London, was an architectural and engineering wonder modeled after the bridge and train shed construction of the mid-nineteenth century. The structure had been designed to be quickly assembled out of prefabricated members and easily rebuilt elsewhere. Its light construction was made possible to use of thin cast iron prefabricated elements combined with wood and a glazed outer shell. The Crystal Palace housed the most spectacular collection of artistic and industrial wonders ever assembled in one place thus far. Visitors came from all over the world to see this display of power at the "Exhibition of the Works of All Nations" which was organized by Prince Albert and Henry Cole (Beaver, 12). The success of the Crystal Palace that cost "a penny per cubic foot" (Hobhouse, 39) brought Joseph Paxton much praise as well as a knighthood. The structure at Hyde Park was designed as a temporary building, able to be constructed and disassembled easily. During the Great Exposition the Crystal Palace housed the works of craftsmen, engineers and artists. The most popular of these exhibits was a crystal fountain made especially for the exhibition (Beaver, 47). The full 33,000,000 cubic feet of Crystal Palace was filled with displays and people crowding the aisles examining these wonders (Hobhouse, 39). When the Fair closed the fate of the Crystal Palace was a topic of extreme importance. Its popularity was obvious and Paxton suggested transforming... ...reat Britain. London: The Arts Council, 1965. Beaver, Patrick. The Crystal Palace, 1851-1936: a portrait of Victorian enterprise. London, Hugh Evelyn Ltd., 1970. Briggs, Asa. Iron Bridge to Crystal Palace: impact and images of the Industrial Revolution. London: Thames and Hudson in collaboration with the Ironbridge Gorge Museum Trust, c1979. Hitchcock, Henry Russell. The Crystal Palace: the structure, its antecedents and its immediate progeny: and exhibition. Northampton, Mass.: Smith College Museum of Art, 1952. Hobhouse, Christopher. 1851 and the Crystal Palace; being an account of the Great Exhibition and its contents; of Sir Joseph Paxton; and the erection, the subsequent history and the destruction of his masterpiece. London, Murray, 1950. Newhall, Beaumont. The History of Photography: from 1839 to the present. New York: Museum of Modern Art. 1982.

How Does Caffeine Affect the Heart Rate of the Daphnia

My results and the graph indicate that as you add the caffeine to the daphnia, the eart rate of the daphnia increases for example the daphnia's heartbeat is 120 without caffeine, however when caffeine is added it is increased to 168. My graph shows a positive correlation and the error bars are also very small which shows that the results have a small range which suggests that my results are accurate and reliable. I think that the experiment was conducted well however there may be some ethical issues surrounding the fact that daphnias are also living species.Therefore, by using daphnias in these experiments may cause a risk for them as there would be little quantities of the species left. This would also affect other living organisms that feed on daphnias for their dietary needs therefore in the experiment we diluted the caffeine solution with distilled water to prevent the daphnia from dying and afterwards, we could put them back in their natural habitats. On the other hand, by doing this experiments it could potentially help us in the future.Also, another problem is that I may have miscounted the daphnias heartbeat due to human errors. However, as I repeated the experiment 3 times, it ensures me that the data is quite accurate. However, if I was to do the experiment again I would do more repeats to make sure the results are reliable and there would be less chance of human error. Also, I would use different concentrations of caffeine to get more accurate comparisons and to see how different concentrations may affect the daphnias heartbeat also. Overall, I think that my results are precise and distinct.

Definition and Examples of the Topoi in Rhetoric