Electronics The WritePass Journal

Electronics Introduction Electronics IntroductionTASK 1: THE 555 TIMER IC.MODES: ASTABLE MODE:MONOSTABLE MODE:BISTABLE MODE:OPERATION:TASK 2:  INTRODUCTION OF FET TRANSISTOR:CONSTRUCTION AND OPERATION OF FETDEPLETION MODE:THE ENHANCEMENT MODE MOSFET:COMAPRISON BETWEEN MOSFET AND BJT:ADVANTAGE OF MOSFET DEVICE:DISADVANTAGE OF MOSFET DEVICE:   USES OF MOSFETs:REFERENCES:Related Introduction In this assignment I would try my level best to fulfill all the condition of the given tasks. I would concern figure of things while attempting the assignment. Firstly, the referencing and the bibliography should be updated timely because it will help me keep in mind where I have got the materials from. Secondly I would try to complete my assignment under the chosen time limit which is very vital. Thirdly all the given tasks should be completed with appropriate information and try to stay within the word count. Lastly, I would try to present my work with clarity and rationality so my hard work should be understood in best possible manner TASK 1: THE 555 TIMER IC. 1a) Before 555 timer came to the market there were large distinct circuits used to carry out the operation of a timer but the compatibility and numerous other advantages of a 555 timer lead the breakthrough .The 555 timer is an integrated circuit designed by Hans R. Camenzind and commercialized by that times leading semiconductors manufacturer signetics. It’s mainly used in variety for timing purposes, producing perfect timing periods through a vast range of time and as a multi vibrator and due to the versatility of the IC it has made conspicuous place in the history of electronics. Never thought by its maker to be so flexible the 555 package consists of numerous transistors, diodes and resistors (depending on the purposes) imbedded on a silicon chip and connected to an 8-pin dual in line package. (D C Green, Electronics 4, third edition, 1995, Longman Scientific and technical) The single 555 timer chip in its basic form is a 8 pin chip consisting of 20 transistors, 2 diodes, 15 resistors. (electronics-tutorials.ws/waveforms/555_timer.html )feb 10, 2011 Above shown fig shows 8 pins which are labeled to show there function. Below is the more detailed function of these pins. Pin no. 1: It is connected to GROUND which connects the 555 timer to the negative 0v supply rail. Pin no. 2: It is the trigger pin. A negative pulse on this pin â€Å"sets† internal flip-flop and start up a timing cycle. Pin no. 3: is an output pin of the 555 timer, it can be connected directly to the inputs of other digital IC’S with the required voltage. Pin no. 4: is the RESET pin which is used to reset the internal flip-flop controlling the output. In other words to terminate the timing cycle. Pin no. 5: is a control voltage pin which can be used to alter the timing aspect of the 555 IC in applications such as frequency modulation. Pin no. 6: is the threshold pin which donates the duration of the timer to ‘output voltage in each of the on/off cycle’ this time phase end when voltage at threshold becomes higher than control voltage pin. Pin no. 7: is a discharge pin which is connected directly to the internal transistor which is used to discharge the timing capacitor to ground. Pin no. 8: is connected to the power supply and the range of voltage depends on the appliance need. MODES: After discussing above the different functions of 555 timers, let’s now discuss about its modes, its usage in different modes. 555 timers IC’s can be used as a multivibrator in three different forms they are as follow: Astable mode Monostable mode Bistable mode ASTABLE MODE: Astable means without a stable state. It has two unstable state means 0 and 1, in other words it continually switch it states to high and low creating a rectangular wave form on its output. There are numerous advantages of this circuit few of them in which it is used are flash lights, LED’S, and security alarm. FIG 2 (kpsec.freeuk.com/images/flashlcd.gif   FEB 10, 2011) FIG 3 (antonineeducation.co.uk/Electronics_AS/Electronics_Module_1/topic_11/topic_11__555_timer_circuit.htm   FEB 10, 2011) For the waveform above we can see how it changed from 0 to 1. For this circuit to become operational we need to consider some of the formulas ‘’The mark time [t(H] is the time at which the output is a 1. t(H)= 0.7(RA + RB)C The space time [t (L)] is the time at which the output is a 0. t(L) = 0.7 RBC The mark to space ratio = mark time à · space time. The astable period T is the time taken for one complete cycle, the mark and the space times added together.   T = mark + space = t(L) + t(H). The frequency = 1 à · period. f =  ____1.4_____ (R1 + 2R2)C The time t (H) will be longer than t (L), unless R1 is very small compared to R2.   If this is the case, then t (H) will be approximately equal to t (L), but not quite equal.   We can say to a first approximation that the mark to space ratio is 1.   This will result in a square wave output’’ ( antonine-education.co.uk/Electronics_AS/Electronics_Module_ 1/topic_11/topic_11__555_timer_circuit.htm FEB 10, 2011 MONOSTABLE MODE: Monostable means circuit which has only one stable state, normally it has two states means stable and unstable. When the voltage is not applied it remains in stable state but as the â€Å"trigger† is pressed it creates electric pulse and switches from stable state to unstable state and remains there for a limited time period which is set and after that it comes back to stable state. This type of circuit is ideal for â€Å"push to operate† system for a model displayed at exhibitions. A visitor push the button to start mechanism of choice and it automatically switch off after a set time. FIG 4 (antonineeducation.co.uk/Electronics_AS/Electronics_Module_1/topic_11/topic_11__555_timer_circuit.htm  Ã‚   FEB 11, 2011) The above diagram shows the circuit of monostable 555 timer. This circuit operates when the switch is closed and released, the voltage at Pin 2 goes up to down and then up. Due to this Pin 7 is discharged from zero and the voltage increases at output. When the voltage across the capacitor (C) gets two third then the output stop and it comes to stable state. The output of this circuit is shown in the FIG below. FIG 5 (antonineeducation.co.uk/Electronics_AS/Electronics_Module_1/topic_11/topic_11__555_timer_circuit.htm   FEB 11, 2011) BISTABLE MODE: Bistable has two stable states, in this mode 555 timer acts as a flip-flop. In this the trigger (which is Pin 2) and reset (which is Pin 4) both are at high state because of the resistors, while the threshold (which is Pin 6) is simply grounded. By taking the trigger LOW it switches to SET position and the output state changes to HIGH and by taking the RESET Pin LOW it switches to reset position and the output will remain LOW. TASK 1(B): A 555 timer is basically used in our daily life as a day/light alarm which can be useful for waking us up from our sleep. Fig 6 free-circuits.com/diagrams/n/14qwe.gif   (March 20, 2011) The components which are used in the above diagram are as follows: 1 Light Dependant Resistor (LDR) 1 transistor 2 set of capacitors both value of 0.01 ÃŽ ¼F 1 555 timer 1 diode 15v/1 µF 3 set of resistor range of 10k, 56k and 3.3 k respectively 1 100k variable resistor 1 speaker 8ohm, 0.5W OPERATION: This above circuit exclusively depends on the light for it to function. A 555 timer is used above and it works on a principle of astable mode with frequency of 1Khz. The transistor is set high because of the changeable resistor when light doesn’t fall on the LDR therefore causing the 555’s reset pin low. Just because of this the timer is reset. It resistance decrease when the light falls on LDR which in turn causes a decrease in base resistance of the transistor alloying current to flow. This will cause the reset pin on the 555 timer to increase and allows the timer to ‘oscillate’ and the speaker starts working by creating sound. TASK 2:  INTRODUCTION OF FET TRANSISTOR: The field effect transistor is a semiconductor device; it depends on its operation to control current by an electric field. FET’s are available in two basic forms and they are: Junction gate field effect transistor (JFET) Insulated gate field effect transistor (IGFET) But the most commonly used transistor is Metal-Oxide semiconductor field effect transistor (MOSFET). It is commonly used because it can be connected as resistor and capacitor, it is cheaper than Bipolar junction transistor (BJT) , it is much smaller in size and there power consumption is much smaller. CONSTRUCTION AND OPERATION OF FET Metal-Oxide semiconductor field effect transistor (MOSFET) is a type of semiconductor which uses three connections which are GATE, SOURCE and DRAIN. The effective width of the channel is controlled by a charge which is placed on gate electrode. The shape of a transistor is like a bar with P-type silicon and two strips which are doped to make N-type material when the metal is deposited to make two terminals DRAIN and SOURCE, then the surface is covered with silicon-oxide which is non-conductor. Then again metal is deposited to form one more terminal called gate which is shown in fig 1. interfacebus.com/JFET-N-Channel-symbol.png (March 20, 2011) After it is completed then the potential of (0V) is applied between the source and drain because of P-N junction there is no current flowing. The P-type material which is source terminal is at 0V, and the gate is already made positive so that it will repel the holes from P-type and turn it temporary N-type. This creates a channel joining two N-type strip so that current flow from drain. If the potential against gain terminal is greater, than the channel will become wider which ends with large current. So to conduct this type, positive voltage is applied to gate. circuitstoday.com/wp-content/uploads/2009/08/n-channel-de-mosfet-structure.jpg (March 20, 2011) Metal oxide semiconductor field effect transistor (MOSFET) is operated in two modes they are: Depletion mode Enhancement mode DEPLETION MODE: Regardless of weather a MOSFET is N-type or P-type material but there are still fundamental difference between depletion mode and enhancement mode. To form a thin layer of silicon-oxide along one side of the channel is easy, and then leave the metal gate region down over the insulator. The gate channel will act as a semiconductor resistance as there Is not current applied to it, P-N junction is not formed nor the depletion layer because the whole conduction of current depends upon the voltage applied between source and drain. If we apply sufficient voltage across source and drain the current will flow through the channel. When negative voltage is applied through the gate terminal it will repel electron charge away from the gate terminal. But as N-type contain majority electron charge carriers by repelling then away from gate the applied negative voltage will create a depletion region. So the process is called Depletion Mode Metal-Oxide Semiconductor Field Effect Transistor. THE ENHANCEMENT MODE MOSFET: Enhancement mode contains two N-type channel and one P-type channel which is sandwiched between both N-type as shown in fig 2. Applying the positive voltage to the drain terminal with respect to source terminal and applying positive terminal to gate terminal. As a result it will attract all the free electrons towards the gate. As the positive voltage is increased the electric field will also become wider and more electrons are attracted. There are free electrons in P-type, source junction is forward biased, so the positive gate voltage can attract electrons towards the gate. The electrons which are attracted towards the gate will enhance the channel within the P-type region as shown in fig 3. This will bridge the gap between source and the drain and it will start FIG 2  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   FIG 3 COMAPRISON BETWEEN MOSFET AND BJT: Metal Oxide Semiconductor Transistor (MOSFET) It is semiconductor device having three active electrodes known as Gate, Source and Drain. Conduction takes place due to either holes or electrons. Hence it is a unipolar Transistor. It is voltage controlled device. Its operation depends upon the flow of majority carriers only. It has high input impedance. It is less noisy than tube or bipolar transistor. There are two type of FETs N-channel P-channel.   It is simpler to fabricate and occupies less space.   It has thermal stability. It can be used as voltage variable resistor. It has very fast switching time. Bipolar Junction Transistor (BJT) It is a semiconductor device consisting of three electrodes known as Base, Emitter and Collector. Conduction takes place due to holes and electrons. Hence it is a bipolar device. BJT is a current controlled device. It operation depend upon the flow of both majority and minority carriers. BJT has low input impedance. BJT device is noisy. There are two type of BJTs NPN and PNP. BJT is difficult to construct and occupies more space. BJT does not have thermal stability. BJT cannot be used as voltage variable resistor. ADVANTAGE OF MOSFET DEVICE: When compared to MOSFET, its switching time is slow Its switching time is 10 times greater than a bipolar junction It has very much switching current. It is less affected by temperature. DISADVANTAGE OF MOSFET DEVICE: It has very high resistance as compared to bipolar transistor. It can be destroyed by high voltage, especially static electricity.    USES OF MOSFETs: MOSFETs can also be used as voltage variable resistor. It is also used as an amplifier. It is also used to prevent power losses. It is used as a switch. It is used as a voltage control device. REFERENCES: Books: Owen Bishop (1995), Understand Electronics, Great Britain, Athenaeum Press Ltd. (electronics-tutorials.ws/waveforms/555_timer.html )feb 10, 2011 (kpsec.freeuk.com/images/flashlcd.gif   FEB 10, 2011) (antonineeducation.co.uk/Electronics_AS/Electronics_Module_1/topic_11/topic_11__555_timer_circuit.htm   FEB 10, 2011) ( antonine-education.co.uk/Electronics_AS/Electronics_Module_ 1/topic_11/topic_11__555_timer_circuit.htm FEB 10, 2011 (antonineeducation.co.uk/Electronics_AS/Electronics_Module_1/topic_11/topic_11__555_timer_circuit.htm  Ã‚   FEB 11, 2011) (antonineeducation.co.uk/Electronics_AS/Electronics_Module_1/topic_11/topic_11__555_timer_circuit.htm   FEB 11, 2011) free-circuits.com/diagrams/n/14qwe.gif   (March 20, 2011) interfacebus.com/JFET-N-Channel-symbol.png (March 20, 2011) circuitstoday.com/wp-content/uploads/2009/08/n-channel-de-mosfet-structure.jpg (March 20, 2011)

Photoelectric Effect and Einsteins 1921 Nobel Prize

Photoelectric Effect and Einsteins 1921 Nobel Prize The photoelectric effect posed a significant challenge to the study of optics in the latter portion of the 1800s. It challenged the classical wave theory of light, which was the prevailing theory of the time. It was the solution to this physics dilemma that catapulted Einstein into prominence in the physics community, ultimately earning him the 1921 Nobel Prize. What Is the Photoelectric Effect? Annalen der Physik When a light source (or, more generally, electromagnetic radiation) is incident upon a metallic surface, the surface can emit electrons. Electrons emitted in this fashion are called photoelectrons (although they are still just electrons). This is depicted in the image to the right. Setting Up the Photoelectric Effect By administering a negative voltage potential (the black box in the picture) to the collector, it takes more energy for the electrons to complete the journey and initiate the current. The point at which no electrons make it to the collector is called the stopping potential Vs, and can be used to determine the maximum kinetic energy Kmax of the electrons (which have electronic charge e) by using the following equation: Kmax eVs The Classical Wave Explanation Iwork function phiPhi Three main predictions come from this classical explanation: The intensity of the radiation should have a proportional relationship with the resulting maximum kinetic energy.The photoelectric effect should occur for any light, regardless of frequency or wavelength.There should be a delay on the order of seconds between the radiation’s contact with the metal and the initial release of photoelectrons. The Experimental Result The intensity of the light source had no effect on the maximum kinetic energy of the photoelectrons.Below a certain frequency, the photoelectric effect does not occur at all.There is no significant delay (less than 10-9 s) between the light source activation and the emission of the first photoelectrons. As you can tell, these three results are the exact opposite of the wave theory predictions. Not only that, but they are all three completely counter-intuitive. Why would low-frequency light not trigger the photoelectric effect, since it still carries energy? How do the photoelectrons release so quickly? And, perhaps most curiously, why does adding more intensity not result in more energetic electron releases? Why does the wave theory fail so utterly in this case when it works so well in so many other situation Einstein's Wonderful Year Albert Einstein Annalen der Physik Building on Max Plancks blackbody radiation theory, Einstein proposed that radiation energy is not continuously distributed over the wavefront, but is instead localized in small bundles (later called photons). The photons energy would be associated with its frequency (ÃŽ ½), through a proportionality constant known as Plancks constant (h), or alternately, using the wavelength (ÃŽ ») and the speed of light (c): E hÃŽ ½ hc / ÃŽ » or the momentum equation: p h / ÃŽ » ÃŽ ½Ãâ€  If, however, there is excess energy, beyond φ, in the photon, the excess energy is converted into the kinetic energy of the electron: Kmax hÃŽ ½ - φ The maximum kinetic energy results when the least-tightly-bound electrons break free, but what about the most-tightly-bound ones; The ones in which there is just enough energy in the photon to knock it loose, but the kinetic energy that results in zero? Setting Kmax equal to zero for this cutoff frequency (ÃŽ ½c), we get: ÃŽ ½c φ / h or the cutoff wavelength: ÃŽ »c hc / φ After Einstein Most significantly, the photoelectric effect, and the photon theory it inspired, crushed the classical wave theory of light. Though no one could deny that light behaved as a wave, after Einsteins first paper, it was undeniable that it was also a particle.

Community development Research Paper Example | Topics and Well Written Essays - 2750 words

Community development - Research Paper Example Data collection methods will include questionnaires and interviews. It is hypothesized that there are visible community development projects in Bangladesh that can be credited to the efforts of Grameen Bank. Additionally, it is hypothesized that there are women who have improved their lives due to empowerment by Grameen Bank. The outcome of this study will have implications on community development workers and agencies (Osmani 695). Since its inception in 1983, Grameen Bank has used an unconventional mode of lending different from other banks by eliminating the need for collateral. The bank has replaced the need for collateral with accountability, mutual trust, supervision, creativity, and participation. The emphasis of the bank is on education and economic empowerment of the poor people who live in the rural areas of Bangladesh. The objective of this study is to document the experience of Grameen Bank in community development and women empowerment in Bangladesh (Mahmud 49). The problems of poverty and women oppression are concerns shared worldwide and different groups and institutions address them in unique ways. Grameen Bank approaches community development and women empowerment from the rural parts of Bangladesh using collateral-free lending. Studies have expressed their admiration for Grameen Bank’s approach to these two concerns. However, prior studies do not provide alternatives to how the bank can ensure that all women remain empowered and that they are not overshadowed by patriarchy and male domination and this is a gap that this study will seek to fill (Mahmud 48). Grammeen Bank started in 1983 from Professor Muhammad Yunus’ idea of providing capital to the poor in Jobra village in Bangladesh. The sight of the poor population of Bangladesh suffering triggered the idea especially in the incidence of the adverse weather conditions of the country (Osmani 696). Famine and poor housing were some

Management and Leadership Development Essay Example | Topics and Well Written Essays - 2250 words

Management and Leadership Development - Essay Example In accordance with the traditional concepts of a leader, he/she is the one with a forceful attitude, who allocates clear agenda and expects his subordinates or followers to carry out and follow his/her commands without imposing any questions. However, in the fast changing commercial environment of the present day, with economic uncertainty ascertaining additional pressure, a single style of leadership does not efficiently match in every situation. Leaders of the present situation should be very much willing to adapt themselves to the various complex situations and simultaneously modify their various techniques and strategies. The truly charismatic leaders use their exquisite personality to charm over their followers and captivate the listeners. This particular form of ability to be able to inspire a strong feeling of attraction is liable to both positive and negative effects. Charismatic leaders are essentially good narrators and draw upon shared imagery to create a feeling of common purpose among its followers. The current American president, Barrack Obama, thoroughly demonstrated this particular phenomenon during his election campaign. Amongst all, one American citizen pointed out that the president’s most efficient talent was his natural ability to communicate difficult ideas comprehensively to his followers, rather than using the much popular yet complicated political words like other ministers practices vividly (The changing face of leadership, n.d., p. 22). Mabey and Lees (2007) in their research proposed that, management development is a potent and high profile human resource activity, involving some of the organizations key players and attracting high investment both in terms of corporate budgets and expectations. For this reason alone, management development requires sustained scrutiny. In the bureaucratized organization, the managers had responsibility for well defined roles such as planning, budgeting, controlling, staffing, and problem solvin g. In the present condition, very few organizations fit to this description of predictability. The decreasing numbers employed in workplaces, and the decline in the number covered by system of consultation and negotiation, have shifted the manager’s power base from positional to personal (Mabey, Lees, 2007, pp.3-4). According to Cornish, transitions and modification in leaderships are fundamental moments in the life span of an organization, and paying adequate attention to them benefits the business organization. However, inspite of having more than sufficient evidence in support to their creation, almost less than 30 percent of the freshly hired employees are devoid of any kind of integration plan. For the women executives who are freshly appointed, the upcoming challenge is much greater. For example in the USA, where 46 percent of the working people are of feminine gender, mere 3 to 5 percent have made it to the upper level of the management in an organization in their corp orate life. Even in this modern world, women are still vulnerable to different organizational barriers towards advancement, which includes, very few role models to whom they can look up to, excluding women from important and essential networks, gender stereotypes and the unavoidable problem of dual role of a woman, i.e. in her corporate life and family life. But this dismal situation can be averted by assigning sponsors to fast track women,

Financial Management Questions Essay Example for Free

Financial Management Questions Essay Question 1:   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Medwig Corporation has a DSO of 17 days.   The company averages $3500 in credit sales each day.   What is the company’s average account’s receivable?   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Answer / Solution:   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Accounts Receivable = Days Sales Outstanding * (Sales / Days)   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚     Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚     Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   = 17 * (3500/1)   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚     Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚     Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   = $59,500 Question 2: Discuss some of the techniques available to reduce risk exposures?   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Answer:   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Insurance is one of the simplest and most available ways to reduce exposure to risk.   It involves the transfer of risk to another company.   Depending on the amount and nature of the risk involved, risk retention by self-insurance might not be a practical option, especially if the cost of transferring the risk (insurance premiums) is reasonable enough to not add significant costs.   Risk transfer is not done always through insurance, however. Outsourcing some operations to a company who agrees to take on the risk involved is another type of risk reduction.   Some tasks are best suited for specialized companies, and large organizations might outsource such activities as customer support, software development and internal security. Derivative hedging is also an option, depending on the nature of the company.   Futures contracts, for example, reduce the risk of price fluctuations in a particular commodity, and are very useful to transfer it to a speculator.   A company producing commodities would benefit from this type of hedge.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Aside from transferring risks, a company might try to reduce risk by reducing the inherent cause of the risk.   Instead of hiring a single custodian for cash transfers, a company might hire another one to reduce the risk of employee theft.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   The last method is to avoid the risk completely.   This will completely circumvent possible losses, but it also precludes any possible gains from taking on the risk.

Franklin Delano Roosevelt FDR :: Biography Biographies Bio

Franklin Delano Roosevelt In March 1933 Franklin Delano Roosevelt became the 32nd president of the United States. During his presidency he was the only president in America's history to hold office for four terms. He led America during the Great Depression and World War II. Franklin Roosevelt was head of the powerful Democratic Party which controlled American politics for thirty years. Roosevelt was a controversial leader in his time, some people admired him and others despised him, but today he is considered to be one of the greatest American presidents. Franklin Roosevelt was born on January 30, 1882 in Hyde Park, New York. Franklin's father, James Roosevelt, married Sara Delano (Franklin's mother) in 1880 several years after his first wife had died. Sara had been only 26 at the time of the marriage while James had been 52. They had a happy marriage until James died in 1900. Franklin was treated as an only child when he was born because his half brother was an adult by then. His parents sheltered and spoiled young Franklin. His parents kept him in dresses and long curls until he was five years old. During the summers Franklin went with his parents to Europe, the seaside of New England, or to the Campobello Island off the Coast of New Brunswick. Since he spent many summers by the sea Franklin Roosevelt developed an interest in sailing. Franklin Roosevelt was home schooled by governesses and tutors until he was fourteen years old. He then attended Groton School in Massachusetts between 1896 and 1900. Franklin's academic record was average and he did not excel at sports either. Some of his class mates called him the "feather duster" because he seemed priggish but that was mostly due to the sheltered life he had led. Franklin then went on to attend Harvard until 1904. His academic record was again average but he finished his B.A. in three years. During his fourth year at Harvard he was editor of the college newspaper, Crimson. Franklin was never very motivated about school. Franklin soon became engaged to Eleanor Roosevelt, a fifth cousin who was once removed. They married on March 17, 1905 despite Sara Delano's objections. They had five children, one girl and four boys. All four of the boys would later serve as officers in World War II. They were all also decorated for bravery. Eleanor Roosevelt discovered in 1918 that Franklin was having an affair with her social secretary, Lucy Mercer.

Activity Analysis

Cost: The price depends on what kind of computer is bought and what type of internet is purchased. A computer can range anywhere from $400. 00 to $1000. 00 and high speed internet usually costs around $20. 00 a month. For this activity an HP computer is being used which costs $429. 99 and high speed internet for $20. 00 a month. Overall cost for one year: $669. 99. Preparation: Must have an email account, know the email address of the person the email is going to, and buy a computer and the internet. Time: 35 min-10 minutes to find email address of the friend and 25 minutes for composing an email. Space Needs or setting required: Indoor, computer desk with computer equipment, well lit area, and an the size of the area does not matter as long as a computer desk and chair can fit. Activity Qualities: Teens, young adults, and adults may find this task meaningful. This task would also be meaningful to businessmen. This activity may not be not enjoyable for the late baby boomers. Occupation: Social participation such as engaging in communication with friends and family. Leisure interest such as relaxation and feeling of involvement by communicating with others. Supervision: None  Precautions: Those with visual impairments, cognitive delays, and proper fine motor control may experience difficulty when performing this task and will need supervision to provide verbal step by step procedures. Contradictions: Not appropriate for those with complete blindness and a major cognitive delay. May not be appropriate for those with profound deficits of gross and fine motor control. Motor Skills: Sensory awareness required. Sensory processing including visual acuity, visual stability, vestibular functions, proprioceptive functions, touch functions, and pressure awareness. Neuromusculoskeletal related functions include joint mobility, joint stability, muscle power, muscle tone, muscle endurance, motor reflexes, and control of voluntary and involuntary movements. Motor skills that are needed for this task are gross, fine, crossing the midline, bilateral integration, and praxis. Also postural control and alignment are important for this task. Process Skills: For this task, attention span, memory, and perception are needed. Also, thought, sequencing, prioritizing, creating, multitasking, and judging are used for this activity. Communication/interaction skills: Interests, self-concept, role performance, social contact, perceive, influence, and relation to others are important to this task. Displaying and perceiving emotions are important to relate to others. Self-control, interpersonal skills, and self-expression are also needed. ADL/IADL Performance Areas: The fine motor skills of sending an email can be helpful in feeding, eating, dressing, bathing, personal device care, and personal hygiene. The cognitive skills of this activity can also help with personal device care and personal hygiene. This activity can also help with communication management by using the communication skills needed to send an email. Work/education performance areas: This activity can be helpful for those seeking employment and job performance. Being able to send an email will enable a person to better their career by sending professional emails. It will also help with job performance by using cognitive, gross, and fine motor control needed to send an email. Leisure/play/social participation areas: This activity can be continued as a leisure activity and can enhance play exploration and participation. It can enhance play by meeting new people and exploring new interests. It can also better social participation by exchanging information with friends and family. Continuous communication with people will improve social skills. Adaptation: Potential for adaptation is very good. May use raised or enlarged keys on the keyboard for those with a visual impairment and low sensory integration. May also increase the zoom on internet pages so a person can see a larger image. With someone who has limited ROM, a wireless keyboard would work best. This way the person can set the keyboard on lap. The mouse can be adapted by enlarging it and adding different texture for the right and left click. This way, the person is aware of the different sides. Grading: Adding wrist weights to hands will improve arm strength. Placing the keyboard and mouse further from the person will encourage reach while sitting. Using a therapy ball instead of a chair will encourage concentration and attention span. Making the keys on the keyboard smaller and the mouse smaller will enhance fine motor control. Disabilities: Those with mental health issues such as depression, anxiety, bipolar disorder, and personality disorder would benefit from this activity by improving social skills and having someone they can talk to. Those with strokes, MS, autism, and rheumatoid arthritis would benefit from this activity which would improve social, cognitive, and fine motor control skills. Goal: Within the OT treatment session, the patient will be able to type 100 words within 10 minutes. Habits: This activity can influence habits by  Environmental Aspects: Sending an E-mail can influence cultural context because for most it is common to use the computer and is the America is beginning to use the internet for sending mail instead of the post office. For personal context, this activity is mainly used by teens, adults, and middle adulthood. For Temporal context, this activity influences it because cards such as, holiday cards, sympathy cards, wedding invitations, and birthday cards are being sent through email. This activity influences virtual context because it is using the internet. It influences social context because it is a quick and easy way to exchange information.