Building A BJT Amplifier Engineering Essay

Building A BJT Amplifier Engineering Essay Students were required to research and design a BJT Amplifier. This amplifier was to be built in the laboratory and tested to verify specifications. Calculations for resistors and capacitors were done and theoretical values were obtained. The circuit was built using Multisim 7 and then simulated to obtain practical values for resistors and capacitors. This is called DC Analysis. When the circuit met the required specifications, building of the BJT Amplifier could begin. Testing of the BJT Amplifier was done using the Feedback FG601 Function Generator which provided an input and a Tektronix 2205 Oscilloscope which showed the output waveform. Also, the Fluke 177 Multi-meter was used when checking for quiescent voltages and currents. The voltage gain, maximum symmetrical swing and the lower cut-off frequency for the BJT Amplifier was tested. The results obtained during tested were compared with the simulated and theoretical results. Success of the BJT Amplifier can only be achieved when the tested values duplicate that of the given specifications. The report that follows records calculations performed, circuits designed and the results of the tests that was done on the BJT Amplifier. List of Abbreviations Voltage gain BJT Bipolar Junction Transistor Current gain Input Impedance Base current Collector current Current across resistor Current across resistor Current across the original emitter resistor Current across the new emitter resistor Current across the unbypassed resistor Resistor used in the potential divider Collector resistor Resistor used in the potential divider Original emitter resistor New emitter resistor (bypassed) Unbypassed resistor Load resistor Base emitter voltage Voltage across the collector and emitter Input voltage Output voltage Voltage across resistor Voltage across the collector resistor Voltage across resistor Voltage across the original emitter resistor Voltage across the new emitter resistor Voltage across the bypassed resistor Introduction It is known that transistors are widely used in electronic devices. This design project is ideal as it enables students to get practical experience in the designing of electrical devices. The practical and theoretical knowledge needed for this design project challenges students as they have to validate calculated values and explain why each process was done. Since the BJT Amplifier has to be designed theoretically, students will understand the limitations provided by the equipment. They will also grasp an appreciation of the simulated circuit model as it relates to the tests performed on the circuit. The theory from Electronics provided valuable knowledge in designing the BJT amplifier. Support was given from lectures based from Engineering Skills and Applications. The practical knowledge was covered in previous laboratory exercises which were designated to familiarizing students with the various equipments. Also, demonstrations were provided by the technicians on the use of the breadboard which is the core building block of the BJT amplifier. BACKGROUND INFORMATION Transistors are important components used in technological devices around the world. Computers, cell phones, and radios are some of the many devices that require transistors as part of their circuit. The transistor is a three terminal, solid state electronic device. In a three terminal device we can control electric current or voltage between two of the terminals by applying an electric current or voltage to the third terminal. This three terminal character of the transistor is what allows us to make an amplifier for electrical signals, like the one in our radio. (cited) The three terminals are the collector terminal, the base terminal and the emitter terminal. There are three possible configurations of a transistor; the common collector, common base and the common collector. In the common emitter amplifier configuration, the emitter terminal is common to both the input and output circuits. The current gain does not have any effect on the collector current , or the collector-emitter voltage . A quiescent point is the operating point of a device which when applied to a device, causes it to operate in a desired fashion. It also refers to the dc conditions of a circuit without an input signal. The Q-point is sometimes indicated on the output characteristics curves for a transistor amplifier. There are different biasing arrangements associated with transistor configurations. These include; simple bias, self stabilizing bias, and H-type bias. The simple bias circuit consists of a fixed bias resistor and a fixed load resistor. For this bias design, the transistor configuration being used is the common emitter. The dc current gain or beta, is the ratio of the dc collector current to the dc base current. This simple bias circuit is similar to the self bias circuit with one difference: the base resistor is returned to the transistor collector instead of the supply voltage. If the transistor used had a high current gain, then the collector voltage would fall. As is connected to the collector then the base current would be reduced to counter the effect. If the transistor had a low value of beta, then the collector voltage would rise. This in turn provides more base current for the transistor to conduct harder and stabilize the q-point. H-TYPE BIASING is the most widely used biasing scheme in general electronics. For a single stage amplifier this circuit offers the best resilience against changes in temperature and device characteristics. The disadvantage is that a couple of extra resistors are required, but this is outweighed by the advantage of excellent stability. The circuits below: The quiescent points are usually fixed for varying collector currents in H-type biasing. If increases, then this will result in an increase in . This increase in the emitter current will flow through the emitter resistor and from the equation V=IR, the voltage across the resistor will increase. This increase in voltage across the emitter resistor will reduce the effective base-emitter voltage resulting in an increase in the stability of the collector current. Also, this type of biasing introduces a potential divider situation, where resistors R1 and R2 fix the base potential of the transistor. With H-type bias, maximum symmetrical sw ing can be calculated. Design OBJECTIVES Various specifications for the design of the BJT Amplifier were given by the rubric. The specifications given are listed in the following; The Voltage Gain must be 50 The Lower Cut-off Frequency must be below 100Hz The BJT Amplifier must be capable of driving a 100KÃŽÂ © load A 15V supply voltage must be used as the source The output voltage must have maximum symmetrical swing A 2N3904 Transistor must be used CHOOSING CONFIGURATION The following transistor configuration comparison chart shows the different types of configurations; Common Emitter Common Base Common Collector (Sedra Smith, 2007) AMPLIFIER TYPE    COMMON BASE      COMMON EMITTER      COMMON EMITTER (Emitter Resistor)      COMMON COLLECTOR (Emitter Follower)   Ã‚  Ã‚   INPUT/OUTPUT PHASE RELATIONSHIP 0 ° 180 ° 180 ° 0 ° VOLTAGE GAIN HIGH MEDIUM MEDIUM LOW CURRENT GAIN LOW  Ã‚ ¡ MEDIUM MEDIUM  Ã‚ ¢ HIGH POWER GAIN LOW HIGH HIGH MEDIUM INPUT RESISTANCE LOW MEDIUM MEDIUM HIGH OUTPUT RESISTANCE HIGH MEDIUM MEDIUM LOW The common emitter transistor amplifier configuration was chosen and not the common base configuration as the common base configuration produces a voltage gain but generates no current gain between the input and the output signals. (Doug Gingrich, 1999) The following figure shows the general configuration of the common emitter transistor amplifier configuration; Figure 1: General configuration of the common emitter transistor amplifier configuration Methodology DC Analysis The function of the DC Analysis is to allow DC biasing of the design to be verified. The DC biasing does not involve capacitors as DC is not transmitted by capacitors. The DC design is mainly used to establish the Q-points in the circuit. Q-points are the operating points in the circuit for which the transistor will perform at optimum performance. The circuit used for the DC Analysis is shown in the following diagram; Figure 2: Circuit used for DC Analysis Choosing and Before DC Analysis could be done, the various components which will be used in the circuit need to be calculated. These components are; , , , . From the specifications given, the voltage supply has a value of 15V and this is used to power the circuit. Before the values of these components could be calculated, the quiescent currents must be known, as well as the current flowing through the potential divider resistor . The data sheet used is based on the 2N3904 transistor. A range for the collector current is given, within which the transistor will operate with optimum performance. Using the Base Emitter ON Voltage vs Collector Current graph found on the data sheet, a value of was read off. The graph used is shown in the following diagram; Figure 3: Graph used to find a collector current The transistor will be built in an environment where the temperature is approximately 25. Hence the 25 line on the graph was used a reference line. From the data sheet, the Base Emitter ON Voltage was given as 0.65V. Hence, using the 25 line and reading off a voltage of 0.65V, the collector current was found to be 1. The base voltage , of the transistor depends on the current flowing through the potential divider. i.e. the current sets the base of the transistor and hence the value of . Any change in the resistance or gain of the transistor would result in an unwanted change in the base current . Also, the potential divider resistors contribute to the input impedance of the amplifier. This input impedance needs to be much more than the output impedance of the function generator. Hence, this is another reason to keep small. was chosen as Calculating The emitter resistor voltage , must be chosen accordingly as this voltage will affect the stability, maximum symmetrical swing and the gain of the amplifier. This voltage should be chosen such that it is greater than the base emitter voltage of the transistor. As mentioned before, the base emitter voltage as taken from the data sheet is 0.65V. This is to ensure that the emitter resistor voltage will not be significantly affected by small changes in . This condition would increase the stability of the transistor. For maximum symmetrical voltage swing, the emitter resistor voltage should be as small as possible. The base current and the collector current will both flow out of the common emitter terminal. Hence, for to remain constant, the base current must be as small as possible to allow negligible current to flow through the base terminal. Assuming the variation possible across the emitter and collector resistors caused variations in is , is calculated using the following equation; (1) The emitter resistor was calculated using the following equation; (2) Calculating From previous statements, For maximum symmetrical swing, half of the remaining voltage should be dropped across the collector resistor . The maximum symmetrical output voltage is calculated using the following equation; (3) Therefore, the voltage across the collector emitter terminal and the collector resistor is 6.75V. From the data sheet, the maximum device dissipation for the NPN 2N3904 transistor is at 25. Since all the power dissipation occurs at the collector junction for the active region, the following equation must be satisfied; (4) This is the range for which the transistor will operate with optimum performance. The power dissipated in the transistor from equation (4) is; , which is well within the specified range. A value for the component was found using the following equation; (5) Calculating and The current flows through the resistor . The value of is calculated using the following equation; (6) Since the current approaches a junction, it splits into and . flows through the potential divider resistor and flows to the base terminal. As previously stated, the base current, must not affect the base voltage by much. Hence the base current is considered negligible and all the current from is assumed to flow through . Hence, is calculated using the following equation; (7) Since some of the component values calculated was not available in stores, the closest value had to be chosen. The standard value that was chosen for each component is shown in the following table; Resistor Calculated Value/ Standard Value/ 6.75 6.8 1.5 1.5 128.5 130 21.5 24 Table 1: Standard values chosen for resistors Calculation of Input Impedance of transistor From the design specifications listed above, the lower cut off frequency must be below 100Hz. Also, as a value for was found using a graph of Current Gain vs Collector Current from the data sheet, a value for was found. The graph used is shown in the following diagram; For a collector current of 1, a gain of 130 was read off from the graph. But since this gain is above the required voltage gain of 50, certain calculations had to be done to reduce this gain and these calculations will be shown in due course. The following equation is used to calculate the input impedance of the transistor; (8) Calculation of Voltage Gain in the Circuit The following equation was used to calculate the voltage gain of the circuit; (9) Calculation of The required voltage gain of the transistor is 50. Hence, in order to reduce this gain, resistors are usually bypassed with the aid of capacitors. In this particular case, the only resistor that needs to be bypassed is the emitter resistor. Using the AC equivalent circuit, the following equation will be used to calculate the value of the unbypassed resistor; (10) where is the unbypassed emitter resistor is From the specification sheet given, is Calculation of new emitter resistor But Hence, if is split into two resistors and , then is found from the following; (11) As there are no standard 1.4kà °Ã‚ Ã…“ ´ resistor is the stores, was used as 1.5kà °Ã‚ Ã…“ ´. The following table illustrates the standard emitter resistors; Resistor Calculated Value/ Standard Value/ 100 100 1400 1500 Table 2: Standard values chosen for emitter resistors CIRCUIT CALCULATIONS Figure 4: Diagram showing circuit analyzed The following circuit calculations involve the standard component values and is based on the circuit in the above diagram.. These circuit calculations show the theoretical value of the quiescent currents and voltages. Theoretical values occur due to the circuit being under ideal conditions. The voltage gain of this circuit will be calculated as well as the maximum symmetrical output voltage across the transistor. The calculations are as follows; which flows through the collector resistor Using the potential divider rule; The voltage drop across is the same as, as both resistors are in parallel. was found on the data sheet as specified previously as . Under ideal conditions, it is assumed that is negligible when compared with as stated previously. for small changes in where is 130 since negligible current flows into the base terminal AC ANALYSIS The AC Analysis is used to calculate the components which would not have worked under DC biasing. These components are , and . If placed in the DC circuit, the capacitors would act as an open circuit, not allowing any current to flow. Also, the input and output impedance of the circuit was calculated. Circuits Used The following circuit was used in the AC Analysis; Figure 5: Circuit used for AC Analysis The following figure illustrates the AC equivalent of the above circuit; Zout Zin Figure 6: Ac equivalent of circuit shown in figure 5 Calculation of Capacitors The capacitor values can now be calculated using the following equation; (12) where is the reactance of the circuit f is the frequency C is the capacitance The capacitors behavior is defined in terms of reactance. The reactance of a capacitor is the ratio of the voltage to the current. The equation relating the reactance to the capacitance is given in equation (12). is the total input impedance of the capacitor (13) where is the input impedance , as the input is taken from the ground to the output terminals of the function generator. (14) Using equation 12; But from the specification sheet, f must be less than 100Hz. f 100 (15) Calculation of For the input coupling capacitor ; Calculation of For the output coupling capacitor ; Where is and Calculation of For the bypass capacitor ; where (16) But As stores does not have these calculated capacitor values, the following standard capacitors were used; Capacitor Calculated Value/ Standard Value/ 0.175 10 0.234 10 14.985 100 Table 3: Standard values chosen for capacitors CIRCUIT CALCULATIONS The following circuit calculations involve the standard component values and are based on the circuit shown in figure 3. These circuit calculations show the theoretical value of the quiescent currents and voltages. Theoretical values occur due to the circuit being under ideal conditions. The voltage gain of this circuit will be calculated as well as the maximum symmetrical output voltage across the transistor. The calculations are as follows; which flows through the collector resistor Using the potential divider rule; (17) The voltage drop across is the same as, as both resistors are in parallel. was found on the data sheet as specified previously as . (18) (19) Under ideal conditions, it is assumed that is negligible when compared with as stated previously. (20) for small changes in (21) where is 130 (22) (23) (24) (25) (26) (27) (28) (29) (30) (31) (32) since negligible current flows into the base terminal Figure 6 was used as a reference point to calculate the voltage gain and input impedance of the circuit. Equation (10) was used to calculate the voltage gain of the circuit; The maximum output voltage swing without clipping is calculated as using the following equation; (33) The following equation is used to calculate the input impedance of the circuit; (34) For simplification in calculation, (35) (36) COMPUTER SIMULATION DC Analysis This design was tested theoretically in the previous section and must now be tested on a computer simulation program. The simulation program used to simulate this circuit is Multisim 7. This software creates the circuit design and simulates the circuit practically and not theoretically. All quiescent voltages and currents were determined as well as the cut-off frequency, voltage gain and maximum symmetrical output voltage. The graph analyzer tool on the Multisim program was used to display these graphs. The following figure illustrates the simulation done for the DC Analysis; Voltage Gain The following circuit was used to observe the voltage gain of the BJT Amplifier; Figure 7: Showing circuit used for DC AnalysisThe voltage gain of the simulated circuit is the ratio of the maximum output voltage to the maximum input voltage. The voltage gain of the circuit is given by the equation; The following figure shows the settings used on the oscilloscope to obtain an input and output waveform; The maximum output and input signals was read off from the graph above using the Interpolator Line. Using the above equation, the voltage gain of the circuit was determined as follows; The following figure illustrates the bode plot obtained from the simulation; This graph was used to find the gain of the circuit using the following equation; From the above equation, the gain, in decibels is related to the above equation. Using the Interpolator Line, the gain, was determined to be 34.34. Hence the voltage gain was calculated as follows; The above calculation indicates that the design circuit would produce a satisfactory gain of approximately 50. Therefore the graph in figure 10 confirms that the design would produce a voltage gain of approximately 50. Cut-off Frequency The following bode plot was used to determine the lower cut-off frequency; The figure above was used to determine the lower-cut off frequency of the circuit. The lower-cut off frequency is the frequency at which the gain of the circuit decreases by 3 decibels. The Interpolator Line was placed at a gain of 30.861decibels, as this is the gain which corresponds to the lower-cut off frequency. The lower-cut off frequency was determined to be approximately . This lower cut-off frequency is much less than 100Hz and thus it meets the required specification. The following bode plot was used to determine the upper cut-off frequency; The figure above was used to determine the upper -cut off frequency of the circuit. The Interpolator Line was placed at a gain of 30.816 decibels, as this is the gain which corresponds to the upper-cut off frequency. The upper-cut off frequency was determined to be approximately . Lab Results The final test done on the designed circuit was done in the year 1 laboratory. The actual resistances and capacitances of the standard components used were measured using the LCR meter. The following table illustrates the measured resistances; Resistor Standard Resistance/ Measured Resistance/ Tolerance/% Lower Tolerance/ Upper Tolerance/ 6.8 6.7638 5 6.46 7.14 1.5 1.503 5 1.425 1.575 100 99.81 5 95 105 130 129.95 5 123.5 136.5 24 23.529 5 22.8 25.2 100 kÃŽÂ © 99.233 5 95 105 TABLE 6: Measured resistances AND THEIR TOLERANCE RANGE The following table illustrates the measured capacitances; Capacitor Standard Value/ Measured Value/ TABLE 8: Showing Measured capacitances used in the laboratory The BJT Amplifier was then built on the solder less breadboard. The DC LQD-421 dual power supply and the function generator were used to supply the input voltages. The following diagram shows the circuit built; As seen above, the capacitors were connected across their respective resistors and the Feedback FG 601 function generator was connected to the input capacitor. Before measuring the quiescent points of the circuit, tests had to be done to ensure that the required gain of 50 was achieved. This was done by connecting a Tektronix 2205 dual trace oscilloscope to the AC bias circuit. The channel 1 lead was connected to the input signal via the input capacitor and the channel 2 lead was connected across the output signal via the load. The settings on the Feedback FG 601 function generator were set to produce a 1kHz sine wave with an amplitude of . The channels on the Tektronix 2205 dual trace oscilloscope were grounded and the signals centered. The DC LQD-421 dual power supply was turned on and set to 15V and the Feedback FG 601 function generator and the Tektronix 2205 dual trace oscilloscope also turned on. The channels were switched to AC and the input and output sine waves appeared on the screen. To obtain a clear waveform on the screen, the following settings were used on the Tektronix 2205 dual trace oscilloscope; The Volts/Div setting was set at The channel 1 setting was set at The channel 2 setting was set at The two waveforms were then used to determine the voltage gain of the BJT Amplifier. Using the following equation; The upper and lower cut-off frequencies were found for the BJT Amplifier. This was done by varying the frequency on the Feedback FG 601 function generator and plotting a graph of Gain vs Frequency. The range used for the Feedback FG 601 function generator was; 10Hz 100Hz for lower cut-off frequency The following table illustrates the frequency and gain for lower cut-off frequency; Frequency/Hz Input/mV Output/V Gain 10 0.01 5 50 20 0.01 5 50 30 0.01 5 50 40 0.01 5 50 50 0.01 5 50 60 0.01 5 50 70 0.01 4.8 48 80 0.01 4.6 46 90 0.01 4.2 42 100 0.01 2.6 26 Table4: showing frequencies used to get varying gain The lower cut-off gain was calculated from the equation; The original setting on the Feedback FG 601 function generator was set so that the maximum symmetrical swing of the BJT Amplifier could be determined using the Tektronix 2205 dual trace oscilloscope. This was done by increasing the frequency of the Feedback FG 601 function generator until clipping of the output waveform was seen. It was noted that the BJT Amplifier did not have maximum symmetrical swing as the negative peak of the waveform started clipping after the positive peak waveform. Hence, the positive swing and negative swing was calculated as shown in the following; Positive swing; Negative swing; The maximum voltage swing was found to be; The original setting on the Feedback FG 601 function generator was set as the effect of removing the bypass capacitor was explored. The equipment was first turned off for safety purposes and the bypass capacitor removed. The equipments was then turned on and the settings on the Tektronix 2205 dual trace oscilloscope configured to obtain a measurable waveform. The gain was then calculated using equation (>>>>). Hence, it can be stated that the gain of the BJT Amplifier decreased considerably when the bypass capacitor was removed. The maximum symmetrical swing for the amplifier was then tested. This was done as follows; The frequency of the Feedback FG 601 function generator was increased until clipping occurred. It was seen that maximum symmetrical swing was not observed as the negative peak of the waveform started clipping before the positive waveform. Hence the swing was calculated for both the positive waveform and the negative waveform. The calculations are as follows; Positive swing; Negative swing; The maximum voltage swing was found to be; The Tektronix 2205 dual trace oscilloscope was disconnected from the circuit and the Fluke 177 Multi-meter was used to measure the quiescent points of the circuit. The probes were placed across the different points and their readings were recorded. The Fluke 177 Multi-meter was set at when measuring currents and at DC voltage when measuring voltages. The DC voltage setting was used as the AC would not yield measurable readings. To measure the quiescent currents, wires were stripped and attached to the leads of the probes. The circuit had to be broken at the quiescent current point being measured. Then the wire attached to the probe was inserted into the solder less breadboard so that the wire was in series with the component removed. The removed component was placed where it was originally to ensure continuity in the circuit. This was repeated at all quiescent points. The following table illustrates the measured currents; The following table illustrates the measured currents; Current Value/ TABLE 5: AC ANALYSIS OF CIRCUIT The following table illustrates the measured voltages; Voltage Value/ 0.676 TABLE 4: AC ANALYSIS Quiescent Values Currents I / mA Voltages V / V Calculated Simulated Measured Current I / mA Voltage V/V Current I / mA Voltage V/V Current I / mA Voltage V/V 0.65 0.663 0.676 DISCUSSION The BJT Amplifier was built using the common emitter configuration. It was H-type biased to increase the stability in the transistor. Also, as is affected with temperature a change, the H-type biasing configuration ensures that changes in is minimal. Also, the resistors used were made from carbon. This means that the resistors are not required to have high temperature stability. Without a biasing arrangement, the BJT amplifier will not turn on because it will not be in the operating region according to the specifications (Boylestad, Nashelsky, 1987). The differences in values for quiescent points obtained can be explained because the calculated and simulated values were found under ideal conditions. The component values used varied from the standard values

The Early English Colonies In America

Early English colonies in America hardly resembled the union of men and women that would later fight against England and build a new country. In fact, until the mid-eighteenth century, most English colonists had very little, if anything to do with the settlers in neighboring colonies. They heard news of Indian wars and other noteworthy events, not from the colony itself, but from England. The colonies in the New World appeared completely different and the prospect of any unity between them seemed impossible. The colonies in New England and the Chesapeake exemplify the many differences in the culture and lifestyles of the settlers, created mainly because of the fact that their founding fathers had held separate intentions when they came to the New World. The New England and Chesapeake colonies were both settled by immigrants from England, the New England colonies being founded by the English from East Anglia, an area in eastern England. Though this was an area thriving with small towns that they had generally liked, they decided to flee England due to religious persecution. Hundreds of families, men, women and their children, came in search of a New World where they could practice their beliefs freely. They founded colonies such as Connecticut, Massachusetts, New Hampshire, and Rhode Island as model Christian societies. Their cities upon the hills were guides, the lanterns, for those lost in the darkness of humanity, as John Winthrop meant by his famous statement. They formed a society of strict religious participation, actually very much resembling their homeland. In the beginning, many called themselves Puritans, and kept things very simple and plain, concentrating on what was important to them. They used the community to achieve their goals, building new towns and enjoying the social aspect of their religion. At the same time, they were committed to remain working hard to keep their community productive. They believed the â€Å"idle hands† were the devil†s workshops. An issue that really defined a split between the societies was the slavery conflict. The northerners in New England held true to their belief that every man shall be equal and no one should be enslaved, while the southerners in the Chesapeake area strongly believed in the use of slavery. At the same time the New Englanders worked to help end slavery by preaching to others about the injustices, they worked diligently to make education in their society strong. Most people in the towns were literate so that they could read their Bibles and study them in detail with their friends and family. Some colonists were artisans or merchants. Others were small-town farmers, making sure that every member of the community had a reasonable share of God†s land. The northern colonies were renowned for being rich in furs, timber and fish. They were especially noted for developing into a very successful trading region. The New England colonies made up the middle class society whose focal points were family, education and religion. The society remained non-capitalistic, yet still buzzed with much activity. On the other hand, the Chesapeake region had a â€Å"cash crop† get rich quickly mentality. This aristocratic region consisted of Virginia and Maryland, two colonies that seemed to be exceedingly materialistic. Evidently, their lives were based more on their liquid assets than on God or family. The Englanders who saw the opportunity to take advantage of the popularity of a brand new crop they had discovered settled the Chesapeake area. These â€Å"gold diggers† were mainly upper-class men of wealthy families aspiring towards coming to the New World to create a large profit for themselves. These colonists were not fleeing England seeking religious or social freedom, but clearly only to add more wealth to their names. Tobacco soon became the primary crop seen growing on almost every one of these wealthy men†s plantations, which created tremendous amounts of money to add to their fortunes. Of course almost every plantation had African slaves working on the land. These colossal estates cam! e to depend on their slaves to run their farms and slavery became a common, yet feared, way of life for many Africans. Unfortunately for these Chesapeake colonies, due to swampy land in much of the area, towns were not part of the landscape or lifestyle as they were in the north. This area was a place of fierce competition with a very minute sense of community, as opposed to the thriving northern colonies surrounded with warm and inviting community towns. The strong focus on family, education or religion was not a main highlight in the lives of Chesapeake colonists, except in Maryland, where the Calvert family did indeed form a haven for Catholics. These two regions of the New England colonies and the Chesapeake colonies did in truth share the common fact that their settlers were all of English origin. Of course when they first set sail, even before they reached the New World, they began to separate into two distinctly different societies already. The clearly evident reason is because these â€Å"pilgrims† came to the New World each pursuing something different. The New England settlers were longing to find a more suitable land of opportunity where they could better their lives and gain religious freedom. They wanted very much to create a society where they could focus on their family, religion and education. Where as the Chesapeake settlers, they were clearly hoping to â€Å"strike gold† in the New World. Many hoped they could improve their social status even more by gaining large profits from growing and selling such items as tobacco. The New England colonists came and made a quite simple society and the Chesapeake colonists created a more aristocratic society. Their society seemed to care more about their wealth and power more than anything, where as the New England society grew to be one with important focus†. These two regions may have shared that same origin and spoken the same English language, but they rarely â€Å"spoke of similar things. † Because of this culture barrier, a separated north and south was created, causing two distinctly different societies to evolve.

The Great Tangshan Earthquake of 1976

The magnitude 7.8 earthquake that struck Tangshan, China on July 28, 1976, killed at least 242,000 people (the official death count). Some observers place the actual toll as high as 700,000. The Great Tangshan Earthquake also rocked the seat of Chinese Communist Party power in Beijing — both literally and politically. Background to the Tragedy — Politics and the Gang of Four in 1976 China was in a state of political ferment in 1976. The Party Chairman, Mao Zedong, was 82 years old. He spent much of that year in the hospital, suffering several heart attacks and other complications of old age and heavy smoking. Meanwhile, the Chinese public and the western-educated Premier, Zhou Enlai, had grown weary of the excesses of the Cultural Revolution. Zhou went so far as to publicly oppose some of the measures ordered by Chairman Mao and his coterie, pushing for The Four Modernizations in 1975. These reforms stood in marked contrast to the Cultural Revolutions emphasis on a return to the soil; Zhou wanted to modernize Chinas agriculture, industry, sciences, and national defense. His calls for modernization incurred the wrath of the powerful Gang of Four, a cabal of Maoist hardliners headed by Madam Mao (Jiang Qing). Zhou Enlai died on January 8, 1976, just six months before the Tangshan Earthquake. His death was mourned widely by the Chinese people, despite the fact that the Gang of Four had ordered that public grief for Zhou should be down-played. Nonetheless, hundreds of thousands of defiant mourners flooded into Tiananmen Square in Beijing to express their sorrow over Zhous death. This was the first mass demonstration in China since the founding of the Peoples Republic in 1949, and a sure sign of the peoples rising anger against the central government. Zhou was replaced as premier by the unknown Hua Guofeng. Zhous successor as the standard-bearer for modernization within the Chinese Communist Party, however, was Deng Xiaoping. The Gang of Four rushed to denounce Deng, who had called for reforms to raise the living standards of average Chinese, allow more freedoms of expression and movement, and end the rampant political persecution that was practiced at that time. Mao fired Deng in April of 1976; he was arrested and held incommunicado. Nevertheless, Jiang Qing and her cronies kept up a steady drumbeat of condemnation for Deng throughout the spring and early summer. The Ground Shifts Beneath Them At 3:42 am on July 28, 1976, a magnitude 7.8 earthquake struck Tangshan, an industrial city of 1 million people in northern China. The quake leveled about 85% of the buildings in Tangshan, which had been built on the unstable soil of the Luanhe Rivers flood plain. This alluvial soil liquefied during the quake, undermining entire neighborhoods. Structures in Beijing also sustained damage, some 87 miles (140 kilometers) distant. People as far away as Xian, 470 miles (756 kilometers) from Tangshan, felt the tremors. Hundreds of thousands of people lay dead after the quake, and much more were trapped in the rubble. Coal miners working deep underground in the region perished when the mines collapsed around them. A series of aftershocks, the most powerful registering 7.1 on the Richter Scale, added to the destruction. All of the roads and rail-lines leading into the city were destroyed by the quake. Beijings Internal Response At the time the earthquake struck, Mao Zedong lay dying in the hospital in Beijing. As tremors rippled through the capital, hospital officials rushed to push Maos bed to safety. The central government, headed by the new premiere, Hua Guofeng, initially knew little of the disaster. According to an article in the New York Times, coal miner Li Yulin was the first to bring word of the devastation to Beijing. Dirty and exhausted, Li drove an ambulance for six hours, going right up to the party leaders compound to report that Tangshan had been destroyed. However, it would be days before the government organized the first relief operations. In the meantime, the surviving people of Tangshan desperately dug through the rubble of their homes by hand, stacking the corpses of their loved ones in the streets. Government planes flew overhead, spraying disinfectant over the ruins in an effort to prevent an epidemic of disease. Several days after the earthquake, the first Peoples Liberation Army troops reached the devastated area to aid in rescue and recovery efforts. Even when they finally arrived at the scene, the PLA lacked trucks, cranes, medicines, and other necessary equipment. Many of the soldiers were forced to march or run for miles to the site due to the lack of passable roads and rail lines. Once there, they too were forced to dig through the rubble with their bare hands, lacking even the most basic tools. Premiere Hua made the career-saving decision to visit the affected area on August 4, where he expressed his sorrow and condolences to the survivors. According to London University professor Jung Changs autobiography, this behavior contrasted starkly with that of the Gang of Four. Jiang Qing and the other members of the Gang went on the air to remind the nation that they shouldnt allow the earthquake to distract them from their first priority: to denounce Deng. Jiang also publicly stated that There were merely several hundred thousand deaths. So what? Denouncing Deng Xiaoping concerns eight hundred million people. Beijings International Response Although the state-run media took the unusual step of announcing the catastrophe to Chinas citizens, the government remained mum about the earthquake internationally. Of course, other governments around the world were aware that a significant earthquake had taken place based on seismograph readings. However, the extent of the damage and number of casualties was not revealed until 1979, when state-run Xinhua media released the information to the world. At the time of the quake, the paranoid and insular leadership of the Peoples Republic refused all offers of international aid, even from such neutral bodies as the United Nations aid agencies and the International Committee of the Red Cross. Instead, the Chinese government urged its citizens to Resist the Earthquake and Rescue Ourselves. Physical Fallout of the Quake By the official count, 242,000 people lost their lives in the Great Tangshan Earthquake. Many experts have since speculated that the actual toll was as high as 700,000, but the true number will probably never be known. The city of Tangshan was rebuilt from the ground up, and now is home to more than 3 million people. It is known as the Brave City of China for its swift recovery from the catastrophic quake. Political Fallout of the Quake In many ways, the political repercussions of the Great Tangshan Earthquake were even more significant than the death toll and physical damage. Mao Zedong died on September 9, 1976. He was replaced as Chairman of the Chinese Communist Party, not by one of the radical Gang of Four, but by Premiere Hua Guofeng. Buoyed by public support after his show of concern at Tangshan, Hua boldly arrested the Gang of Four in October of 1976, ending the Cultural Revolution. Madam Mao and her cronies were put on trial in 1981 and sentenced to death for the horrors of the Cultural Revolution. Their sentences were later commuted to twenty years to life in prison, and all were eventually released. Jiang committed suicide in 1991, and the other three members of the clique have since died. Reformer Deng Xiaoping was released from prison and politically rehabilitated. He was elected Party Vice Chairman in August of 1977 and served as the de facto leader of China from 1978 through the early 1990s. Deng initiated the economic and social reforms that have allowed China to develop into a major economic power on the world stage. Conclusion The Great Tangshan Earthquake of 1976 was the worst natural disaster of the twentieth century, in terms of loss of life. However, the earthquake proved instrumental in ending the Cultural Revolution, which was one of the worst man-made disasters of all time. In the name of the Communist struggle, the Cultural Revolutionaries destroyed the traditional culture, arts, religion, and knowledge of one of the worlds most ancient civilizations. They persecuted intellectuals, prevented the education of an entire generation, and ruthlessly tortured and killed thousands of ethnic minority members. Han Chinese, too, were subject to hideous mistreatment at the hands of the  Red Guards; an estimated 750,000 to 1.5 million people were murdered between 1966 and 1976. Although the Tangshan Earthquake caused tragic loss of life, it was key in bringing an end to one of the most horrific and abusive systems of governance that the world has ever seen. The quake shook loose the Gang of Fours hold on power and ushered in a new era of relatively increased openness and economic growth in the Peoples Republic of China. Sources Chang, Jung.  Wild Swans: Three Daughters of China, (1991). Tangshan Journal; After Eating Bitterness, 100 Flowers Blossom, Patrick E. Tyler, New York Times (January 28, 1995). Chinas Killer Quake, Time Magazine, (June 25, 1979). On This Day: July 28, BBC News Online. China marks 30th anniversary of Tangshan quake, China Daily Newspaper, (July 28, 2006). Historic Earthquakes: Tangshan, China U.S. Geological Survey, (last modified January 25, 2008).

The Experience of Suffering in John Steinbecks Grapes of...

Imagine going down south to the Promised Land (California), getting a new job that pays very and well. Finally have enough food on the table for the entire family in order for them to survive and not die of starvation. The ideal American Dream for all the migrants who are hardly surviving the Great Depression and the Dust Bowl. John Steinbeck’s ultimate goal by writing this phenomenal, very controversial and outrageous novel was to bring the reader back in time in order for them to experience the life of the migrants suffering during the great Depression but also to criticize all the high authorities—most particularly in the farming industry—who have mistreated the migrants and given them false hopes. Steinbeck’s clever use of a raw†¦show more content†¦We see this as the reader follows the journey of one family (the Joads) that are willing to do the impossible in order to survive as a family. Unfortunately, every moment they manage to find hope, it is all destroyed. The intelligence behind the creation of his characters again puts an earthy and realistic touch to the novel in order to grasps its readers. Finally, As Steinbeck shifts the tone and the mood than something different than the Joads and their engagement; this makes the fluency of the story have a positive toll throughout the novel. For example, we see this in Chapter 7 when the author observes in a critical manner the economic system in the farming industry in general. It is also seen when the car dealers cannot afford profit by misery. Furthermore, the sales are faster and pressured and consequently, the pacing and tone becomes unfeeling and exploitive. By doing this, Steinbeck manages with great success in his passages to rarely get â€Å"bogged† down in detail and so the readers’ eye would never end up lingering too long on the same page. All this said, as much as the novel is still considered outrageous throughout several southern states in the USA till this day, John Steinbeck has greatly managed to captivate his readers but also revolutionize in his own manner the society of that era in order for it to become the pillar to strengthen ofShow MoreRelated Humanitys Journey in Steinbecks The Grapes of Wrath Essay1150 Words   |  5 PagesHumanitys Journey in Steinbecks The Grapes of Wrath As a major literary figure since the 1930s, Steinbeck displays in his writing a characteristic respect for the poor and oppressed. In many of his novels, his characters show signs of a quiet dignity and courage for which Steinbeck has a great admiration. For instance, in The Grapes of Wrath, Steinbeck describes the unrelenting struggle of the people who depend on the soil for their livelihood. 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