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Describe the difference of clipping and climping circuits. Analyze inverting amplifier, non-inverting amplifier, summing amplifier and multistage of op-amp circuits. Part 1A :Fundamental of basic electrical instrument. Theory :The oscilloscope, often just called the scope, displays the signals as a plot of magnitude versus time. It is an electronic test instrument that displays electrical signals graphically, usually as a voltage (vertical or Y axis) versus time (horizontal or X axis) as shown in figure 1. The intensity or brightness of a waveform is sometimes considered the Z axis. There are some applications where other vertical axes such as current may be used, and other horizontal axes such as frequency or another voltage may be used.. A signal or function generator is used to produce periodic signals of the frequency, amplitude, and waveform needed for input to the device under test. The counter/timer can measure time intervals and frequencies very accurately, and the digital multimeter measure voltages, currents, resistance, and it can test silicon diodes and transistors. Everything you do in an electronics laboratory depends upon your familiarity with these instruments. Equipments :1-oscilloscop. 2-function generator. 3-probe. 4-resistors(1kohm,5kohm). 5-wire/jumper. Procedures:? First of all, all the switches of the oscilloscope was studied and a adjusted to various values. ? The function generator was adjusted to a 1000 Hz sinusoidal waveform. ? On the oscilloscope, the vertical sensitivity was set to 1V/div. ? Finally the amplitude control of the function generator was adjusted to a 4V peak-to-peak (p-p) sinusoidal waveform on the screen of the oscilloscope. ? Then the circuit in the below figure was constructed. The function generator was set to sin wave output and frequency to 100Hz. ? The probe and ground clip of the scope were connected to point A and C. ? Then the scope was turned on, and th AC-GND-DC was set to AC coupling. ? The amplitude control of function generator and the scope’s controls were adjusted to produce a single sin wave with 6Vp-p. ? VOLTS/DIV settings and the value were recorded in a table. ? Then TIME/DIV was adjust ed until an appropriate size of signal is achieved. After this the data was recorded in a table. Finally, the same steps were done to measure the voltage across point B and C. Results :VOLTS/DIV (V/div) output Voltage (V)P-P TIME/DIV(ms/div) Time division (ms) A to C 1 6 2 10. 4 B to C 1 5. 2 2 10. 4 Discussion :As can be seen from the table above, the voltage between A and C is bigger than the voltage from B to C. This is a result of the bigger resistance between A to C, which was 5Kohm while the resistance between B an C was just 1Kohm. Accordingly as long as the resistance is increased the voltage will simultaneously will be increased. Conclusion :To sum up this experiment, all the objectives were successfully approached, and students were able to deal the instruments correctly. Reference :http://en. wikipedia. org/wiki/Oscilloscope part 2A :Characteristics of BJT (Bipolar Junction Transistor) Theory :A bipolar (junction) transistor (BJT) is a three-terminal electronic device constructed of doped semiconductor material and may be used in amplifying or switching applications. Transistor is an abbreviation to Transfer resistor. The three terminal of BJT are called, emitter, collector and base. There are two types of transistor which is pnp and npn transistor.. The functional difference between a PNP transistor and an NPN transistor is the proper biasing (polarity) of the junctions when operating. Equipments :1. Digital multimeter 2. DC power supply 3. Transistor( 2N3904) 4. Resistors (1k? ,330K? ) 5. Potentiometer(5K? ,1M? ) 6. Wire/jumper Procedures 😕 the three terminals of the given transistor were determined by using digital multimeter. ? The digital multimeter was set to the 2Kohm range, then the terminals were tested based on the table shown below in the results. Finlly, based on the data obtained from the table terminals, type of transistor and it’s material were identified. Results :Multimeter Polarity position Positive negative 1 2 2 1 3 2 3 1 3 1 3 2 RESULT (READING) ? 0. 725 ? ? 0. 730 ? Discussion :According to the results obtained, the transistor was NPN type. Because as we can see the table above shows that when we connected 1 st terminal to the positive terminal of the multimeter, and the 2nd terminal to the negative terminal of the multimeter we could not obtain any value. On the hand, when we reversed the polarities we could obtain the values recorded above. Conclusion :To make it short, all objectives of the experiment were conducted to the students and could be understood well. Dealing with transistor and the ability to determain it’s terminals was also a new ability the students approached. References :http://en. wikipedia. org/wiki/Bipolar_junction_transistor Note : This part is to determine the collector characteristics. Theory :In electronics, a common-collector amplifier (also known as an emitter follower or BJT voltage follower) is one of three basic single-stage bipolar junction transistor (BJT) amplifier topologies, typically used as a voltage buffer. In this circuit the base terminal of the transistor serves as the input, the emitter is the output, and the collector is common to both. Procedures 😕 The network was constructed. ? The voltage Vrb was set to 3. 3V by varying the 1-Mohm potentiometer. Which will lead the Ib= Vrb/Rb to 10 microA. ? Then Vce was set to 2V by vatying the 5-Kohm potentiometer as required by the first line of the table shown in the results. ? Then Vrcand Vbe were measured, by using the mV scale of the multimeter for Vbe. ? For each value of Vce, Vrc and Vbe were measured and recorded. Then the values of Ic was computed using the equation of Ic= Vrc/Rc and Ie using the equation if Ie= Ic+Ib. ? Finally the levels of alpha and beta of each in the table shown in the results were calculated. Results :- Vrb(V) (meas) 3. 3 6. 6 9. 9 Ib(microA) (calc) Vce(V) (meas) 10 2 6 10 20 2 6 10 30 2 6 10 Vrc(V) (meas) 2. 70 2. 82 2. 93 5. 37 5. 60 5. 74 7. 91 8. 58 Not procees Vbe(V) (meas) 0. 68 0. 67 0. 67 0. 69 0 . 68 0. 68 0. 70 0. 69 Not proceed Calculations :Ic = Vrc/Rc Rc = 1Kohm Ic = 2. 70/1Kohm = 2. 70mA Ic = 2. 82/1Kohm = 2. 82mA Ic = 2. 3/1Kohm = 2. 93mA Ic = 5. 37/1Kohm = 5. 37mA Ic = 5. 60/1Kohm = 5. 60mA Ic = 5. 74/1Kohm = 5. 74mA Ib(microA) 10 20 30 Ic(mA) 2. 70 2. 82 2. 93 5. 37 5. 60 5. 74 7. 91 8. 58 Not proceed Ie(mA) 2. 71 2. 83 2. 94 5. 39 5. 62 5. 76 7. 94 8. 61 Not proceed alpha 0. 996 0. 996 0. 997 0. 996 0. 996 0. 997 0. 996 0. 997 Not proceed Beta 270 282 293 269 280 287 264 286 Not proceed Discussion :Based on the table shown above, The low output impedance allows a source with a large output impedance to drive a small load impedance; it functions as a voltage buffer. In other words, the circuit has current gain (which depends largely on the hFE of the transistor) instead of voltage gain. A small change to the input current results in much larger change in the output current supplied to the output load. Conclusion :To sum it up, To make it short, all objectives of the experiment were conducted to the students and could be understood well. In addition to that, characteristics of a transistor collector were conducted to the students since the experiment was done by them. Refrences :http://en. wikipedia. org/wiki/Common_collector Part 3A :Voltage regulator Theory :A voltage regulator is an electrical regulator designed to automatically maintain a constant voltage level. A voltage regulator may be a simple feed-forward design or may include negative feedback control loops. It may use an electromechanical mechanism, or electronic components. Depending on the design, it may be used to regulate one or more AC or DC voltages. Equipments :1. Digital multimeter 2. Resistors (390k? , 2? 1K? , 5k? , 2? 2k? , 5k? , 10k? , 20k? ) 3. Zener diode(BZX79 5. 1V) 4. Transistor(NPN BD 135) 5. Wire/jumper Procedures 😕 The circuit below was constructed. ? Output voltage Vout was measured and recorded in the table shown in the results when Vin was changed (7V-15V) while the Rl was fixed by using 20Kohm. ? The line regulation was calculated from the measured values. ? Output voltage Vout was measured and recorded, when the Rl was changed while Vin is fixed at 15V. ? Load regulation was calculated from measured values. Note :- this is series voltage regulator. Result :When Vin was changed and Rl was fixed (20 Kohm) :Line Regulation = (Vout/ Vin) x 100% Vin (V) 7 8 9 10 11 12 13 14 15 Vout (V) 6. 9 7. 99 8. 89 9. 94 10. 98 11. 81 12. 87 13. 90 14. 95 Line Regulation (%) 98. 5 99. 8 98. 7 99. 3 99. 1 98. 6 99. 7 99. 3 99. 5 When Rl was changed and Vin was fixed (15V) :Load Regulation = (( Vnl – Vfl ) / Vfl) x 100% R (Kohm) 1 2 4 10 20 Vin (V) 15 15 15 15 15 Vout (V) 14. 66 14. 66 14. 68 14. 79 14. 66 Load Regulation (%) 2. 25 2. 25 2. 19 2. 06 0. 31 Note :- this is shunt voltage regulator. Result :When Vin was changed and Rl was fixed (20Kohm) :Line regulation = (Vout / Vin) x 100% Vin (V) 7 8 9 10 11 12 13 14 15 Vout(V) 6. 82 7. 88 8. 9 9. 76 10. 71 11. 75 12. 79 13. 68 14. 79 Load regulation (%) 97. 4 98. 6 97. 6 97. 7 97. 2 97. 92 98. 2 97. 7 98. 4 When Rl was changed and Vin fixed (15V) :Load Regulation = ((Vnl – Vfl) / Vfl) x 100%. R (Kohm) 1 2 10 20 Vin(V) 15 15 15 15 Vout(V0) 11. 72 12. 51 14. 45 14. 73 Load Regulation (%) 28. 12 20. 12 3. 96 2. 06 Discussion :From the results obtained above we can say that Line regulation is the capability to maintain a constant output voltage level on the output channel of a power supply despite changes to the input voltage level. And Load regulation is the capability to maintain a constant voltage (or current) level on the output channel of a power supply despite changes in load. Conclusion :All the objectives of the experiment and approaches were successfully conducted to student and understood well. Since the experiment was done by themselves. References :http://en. wikipedia. org/wiki/Voltage_regulator#Electronic_voltage_regulators http://en. wikipedia. org/wiki/Line_regulation http://en. wikipedia. org/wiki/Load_regulation