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Katie Seifert 68469311 2019/10/24 Elec 301 101: Mini Project 2 Single Transistor Amplifiers
The Power of Trust. The Future of Energy. Table of Contents 1 INTRODUCTION ................................................................................................................................... 3 2 GENERAL INFORMATION ................................................................................................................... 3 2.1 Purpose ........................................................................................................................................ 3 2.2 ......................................................................................................................................................... 3 2.3 Tests Performed ........................................................................................................................... 3 3 PART 1 - COMMON EMITTER MODELLING AND BIASING ............................................................... 4 3.1 Part A ........................................................................................................................................... 4 3.2 Part B ........................................................................................................................................... 4 3.3 Part C ........................................................................................................................................... 5 3.4 Part D ........................................................................................................................................... 7 3.4.1 2N3904 ............................................................................................................................................. 7 3.4.2 2N4401 ............................................................................................................................................. 8 4 PART 2 – COMMON EMITTER AMPLIFIER SIMULATION .................................................................. 9 4.1 Part A ........................................................................................................................................... 9 4.2 Part B ......................................................................................................................................... 10 4.3 Part C ......................................................................................................................................... 10 4.4 Part D ......................................................................................................................................... 11 4.5 Part E ......................................................................................................................................... 11 4.5.1 2N3904 ........................................................................................................................................... 11 4.5.2 2N4401 ........................................................................................................................................... 13 4.5.3 Transistor Comparison ................................................................................................................... 14 5 PART 3 – COMMON BASE AMPLIFIER SIMULATION ...................................................................... 15 5.1 Part A ......................................................................................................................................... 15 5.2 Part B ......................................................................................................................................... 15 5.3 Part C ......................................................................................................................................... 16 5.4 Part D ......................................................................................................................................... 16 APPENDIX A: COMMON EMITTER MODELLING AND BIASING TEST DATA ....................................... 17 APPENDIX B: COMMON EMITTER AMPLIFIER SIMULATION TEST DATA ........................................... 19 APPENDIX C: COMMON BASE ACOMPLIFIER SIMULATION TEST DATA ........................................... 23 APPENDIX D: REFERENCES ................................................................................................................... 25 Elec 301 101: Mini Project 2 Page 1 of 26 Katie Seifert 68469311 2019-10-24
The Power of Trust. The Future of Energy. 1 INTRODUCTION In order to analyse and measure the characteristics of two important transistor amplifiers with 3 commonly available transistors, as well as develop familiarity with the hybrid-π model and the issues surrounding the biasing of transistors, mini project 2 was conducted. This report summarizes the results of the tests performed. 2 GENERAL INFORMATION 2.1 Purpose The purpose of the tests was to model the Common Emitter and Common Base amplifiers using three commonly available transistors (as shown in Figure 8 – Tested circuit and Figure 19), as well as bias the circuits (shown in Figure 7) using simulated and calculated values and compare biasing methods as taught in lecture. 2.2 2.3 Tests Performed Part 1 – Common Emitter modelling and biasing a) Datasheet investigation b) Parameter simulation c) Bias in the active region d) Different transistors i. 2N3904 ii. 2N4401 Part 2 – Common Emitter amplifier simulation e) Bode plot simulation and comparison f) Mid band modelling g) Input impedance h) Output impedance i) Different transistors and comparison i. 2N3904 ii. 2N4401 Part 3 – Common Base amplifier simulation a) Bode plot simulation and comparison b) Mid band modelling c) Input impedance d) Output impedance Elec 301 101: Mini Project 2 Page 2 of 26 Katie Seifert 68469311 2019-10-24
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The Power of Trust. The Future of Energy. 3 PART 1 - COMMON EMITTER MODELLING AND BIASING 3.1 Part A Research: Using the online datasheet 4 for the 2N2222A, the H-parameters and therefore the hybrid-π model values were determined. This was done by assuming that the transistor was a small signal model and then determining the hybrid-π values by using their corresponding H-parameter values. For the calculations, h fe = β, h ie = r π and h oe = 1/r o were used to determine the hybrid-π parameters. Evaluation: Table 1 – Datasheet 4 Values Component Min Value Max Value h fe 50 300 h ie 2 kΩ 8 kΩ h oe 5 μΩ -1 35 μΩ -1 β 50 300 r π 2 kΩ 8 kΩ r o 28.57 kΩ 200 kΩ 3.2 Part B Simulation: Using SPICE software, the circuit shown in Figure 1 was modelled with the primary varying parameter V BE and the secondary varying parameter I B and produced the graph seen in Figure 2. Following this, the circuit shown in Figure 3 was modelled with the primary varying parameter V CE and the secondary varying parameter I B and produced the graph seen in Figure 4. Finally, the circuit shown in Figure 5 was modelled with the primary varying parameter V CE and the secondary varying parameter V BE and produced the graph seen in Figure 6. These plots produced were used to graphically determine the β, r π , g m and r o using the calculation methods described below. Calculation: Using the graph shown in Figure 4 and the provided information that V CE = 5 V and I C = 1 mA, I B can be determined to be 6 μA. This is done by following the current steps of I C and determining the value at the operating point provided. From this β can be calculated as follows. I C = β I B = 1 10 3 = β 6 10 6 = β = 166.7 Following this calculation, g m can be calculated following the method below, following the provided information that the transistor is functioning at 25°C, that V T = 0.025 V. g m = I C V T = 1 10 3 0.025 = 0.04 1 Using the calculated g m and β, r π can be determined using the following calculations. r π = β g m = 4.1667 kΩ Elec 301 101: Mini Project 2 Page 3 of 26 Katie Seifert 68469311 2019-10-24
The Power of Trust. The Future of Energy. To determine the r o , the early voltage V A must first be determined graphically. V A can be found by determining the slope of the linear region of the transistor where I C = 1 mA and I B = 1 μA and then determining the Y-axis crossing. Using this, the line equation can be found, and V A can be determined to be where the line crosses the X-axis using the following calculations. y = 0.872 10 5 x + 0.9578 10 3 where x = voltage and y = current Using y = 0, V A can be determined as follows. 0 = 0.872 10 5 x + 0.9578 10 3 = x = 109.84 V = V A After having determined V A , r o can be found using the following calculations. r o = V A I C = 109.84 1 10 3 = 109.8 kΩ Finally, V BE can be found and used in future calculations by using graphical determination and found to be V BE = 0.6 V. Evaluation: Table 2 – Measured vs Datasheet 4 Values Component Min Value Max Value Measured Value β 50 300 166.7 r π 2 kΩ 8 kΩ 4.1667 kΩ r o 28.57 kΩ 200 kΩ 109.8 kΩ These values are well within the range provided by the datasheet 4 and are close, however slightly above, the average of each component. Furthermore, although the average can be calculated, the expected value of each component is not provided, therefore there can be no further analysis of the expected vs calculated values past comparing them to the expected range. Comparing to the simulated waveforms, g m can be determined to be within expected values and is considered to be within an appropriate range. 3.3 Part C Calculations: The circuit used in biasing is shown in Figure 7. We calculate all biases using the provided information that V cc = 15 V and I C = 1 mA. First biasing in using the parameters calculated from the curves, using the V BE , I C and I B values calculated in the section 3.2 and the provided knowledge that V CE ≤ 4 V and that R E = 0.5* R C we are able to calculate R C using the following equations. 4 V = 15 V ( 1 mA R C + ( 1 mA + 6 µA ) 1 2 R C ) = R C = 7.3187 kΩ Then using the provided relationship between R E and R C , R E = 3.65935 kΩ We then need to determine R B1 and R B2 . To do so, we begin by determining V E and V B using the following calculations. Elec 301 101: Mini Project 2 Page 4 of 26 Katie Seifert 68469311 2019-10-24
The Power of Trust. The Future of Energy. I E = ( I C + I B ) V E = R E ( I C + I B ) = 3.68 V V B = V BE + V E = 4.28 V We can now determine R B1 and R B2 . To do so, we begin by finding a ratio between the two resistor values as we are unable to determine exact values. We do so by doing the following calculations. V CC V B R B 1 = I B + V B R B 2 = R B 2 = 2140000 R B 1 5360000 3 R B 1 Using this ratio, we pick a resistors values that are common resistor values or are within error measurement of a common resistor value. Furthermore, we must pick resistor values that limit power loss, therefore they should be on the magnitude of 10 5 Ω. By trial of different resistor values from the common resistor sheet 3 , we are able determine the resistor values as follows. R B 1 = 110 kΩ R B 2 = 46.799 kΩ 47 kΩ We then bias using the 1/3 rd rule. We bias using the V BE , I C and I B values calculated in the section 3.2 as well as the 1/3 rd rule equations as shown below. V B = 1 3 V CC = 5 V V C = 2 3 V CC = 10 V V E = V B V BE = 4.4 V Having calculated β in section 3.2 and found it to be 166.7, we are able to calculate I B1 and I B2 as follows. I B 1 = I E B = I C + I B B = 77.92 µA I B 2 = I B 1 I B = 71.92 µA Having determined the voltage and current values at each node, we are able to determine the resistor values using ohm’s law as follows. R C = V CC V C I C = 5 kΩ R E = V E I E = 4.373 kΩ R B 1 = V CC V B I B 1 = 128.330 kΩ R B 2 = V B I B 2 = 69.518 kΩ Elec 301 101: Mini Project 2 Page 5 of 26 Katie Seifert 68469311 2019-10-24
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The Power of Trust. The Future of Energy. Finally, we bias using common resistor values found on the resistor reference sheet 3 closest to the resistor values determined above using the 1/3 rd rule. The resistor values are as follows. R C = 5.1 kΩ R E = 4.3 kΩ R B 1 = 130 kΩ R B 2 = 68 kΩ The DC operating points were determined using a simulation of the circuit shown in Figure 7 – Tested circuitand measuring the voltage and current at each node. Evaluation: Table 3 – DC Operating Point Values and Comparison DC operating point Measured Value 1/3 Bias Value Common Resistor Value I C 1.001 mA 1.003 mA 993.3 µA I E 1.007 mA 1.008 mA 999.2 µA I B 6.044 µA 5.976 µA 5.923 µA V C 7.689 V 9.998 V 9.946 V V E 3.678 V 4.401 V 4.287 V V B 4.279 V 5.002 V 4.888 V V CE 4.011 V 5.597 V 5.597 V When comparing the values of the measured value bias, 1/3 rd rule bias and common resistor bias, we can see that all are within a small margin of error and are all valid biasing methods. Although the measured value bias is the best method for this transistor due to it’s close proximity to the desired bias, the 1/3 rd method using the common resistor values would be the most economical and most likely to be used in industry, as it is accurate within the percent error of common resistor values (±10%) and saves time and is the easiest to use for any person working within industry as it would be cheaper and easier to acquire. 3.4 Part D 3.4.1 2N3904 Calculations: Following the parameter measurement methods described in section 3.2, we are able to determine the parameter values of the 2N3904 transistor. The determined values are as follows. V BE = 0.648 V β = 114.3 r π = 2.8575 kΩ r o = 99.8735 kΩ I B = 8.75 µA g m = 0.04 1 The DC operating points were determined using a simulation of the circuit shown in Figure 7 – Tested circuit and measuring the voltage and current at each node. Evaluation: Elec 301 101: Mini Project 2 Page 6 of 26 Katie Seifert 68469311 2019-10-24
The Power of Trust. The Future of Energy. Table 4 – DC Operating Point Values and Comparison DC operating point Measured Value 1/3 Bias Value I C 964.9 µA 965.6 µA I E 973.1 µA 973.7 µA I B 8.259 µA 8.164 µA V C 7.940 V 10.17 V V E 3.560 V 4.257 V V B 4.206 V 4.902 V V CE 4.38 V 5.913 V When comparing the biasing of the 2N3904 with that of the 2N2222A, it is clear that the measured bias is less accurate for the 2N3904 and varies greatly across transistors. While this method was most accurate for the 2N2222A, it is less versatile and looses accuracy with changing transistors. This demonstrates the validity of using the 1/3 rd rule in biasing a variety of transistors, as over a range of multiple transistors, it is most accurate and allows for more versatile usage. Additionally, each transistor will have a range of β values as provided by their data sheet, and the 1/3 rd rule allows easier accommodation for a range of β values. 3.4.2 2N4401 Simulation: Following the parameter measurement methods described in section 3.2, we can determine the parameter values of the 2N4401 transistor. The determined values are as follows. V BE = 0.659 V β = 142.86 r π = 3.5715 kΩ r o = 107.107 kΩ I B = 7 µ A g m = 0.04 1 The DC operating points were determined using a simulation of the circuit shown in Figure 7 – Tested circuit and measuring the voltage and current at each node. Evaluation: Table 5 – DC Operating Point Values and Comparison DC operating point Measured Value 1/3 Bias Value I C 977.8 µA 981.6 µA I E 985.5 µA 988.2 µA I B 6.732 µA 6.679 µA V C 7.851 V 10.10 V V E 3.599 V 4.313 V V B 4.888 V 4.970 V V CE 4.252 V 5.787 V When comparing the biasing of the 2N4401 with that of the 2N2222A, it is clear that the measured bias is less accurate for the 2N4401 and varies greatly across transistors. While this method was most accurate for the 2N2222A, it is less versatile and looses accuracy when changing transistors. This demonstrates the validity of using the 1/3 rd rule in biasing a variety of transistors, as over a range of multiple transistors, it is most accurate and allows for more versatile usage. Additionally, each transistor will have a range of Elec 301 101: Mini Project 2 Page 7 of 26 Katie Seifert 68469311 2019-10-24
The Power of Trust. The Future of Energy. β values as provided by their data sheet, and the 1/3 rd rule allows easier accommodation for a range of β values. Elec 301 101: Mini Project 2 Page 8 of 26 Katie Seifert 68469311 2019-10-24
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The Power of Trust. The Future of Energy. 4 PART 2 – COMMON EMITTER AMPLIFIER SIMULATION 4.1 Part A Simulation: Using SPICE software, the circuit shown in Figure 8 – Tested circuit was simulated and the Bode plots showing the magnitude and phase were noted in Figure 9 and Figure 10. Using the plots, we can graphically determine and confirm that the circuit is a band-pass filter. Calculations: An example of the graphically determined poles is shown in Figure 11, demonstrating how poles were determined from the Bode plot of a simulated circuit. The graphically determined values are shown in Table 6 - Pole Locations. The values were determined by estimation, as the frequencies are located after the steepness of the slope begins to change. This was determined using estimation, as well as measurement and observation. The pole values were calculated using the Open Circuit and Short Circuit (OC and SC) method. In this method, all capacitors will act as open circuits before their pole frequency is reach, once their pole frequency has been passed, they then begin to act as short circuits. To calculate the frequency ω p , we first find the time constant τ . We do so by opening all capacitors with a lower value than the capacitor of interest and shorting all capacitors of a higher value, as well as the voltage source. From this, the equivalent resistance of the circuit seen by the capacitor of interest may be calculated and therefore we are able to calculate τ = RC . From this we can determine ω p = 1 τ . The zero are calculated similarly, determining at what value the admittance of a branch would be 0. To begin, the low frequency poles and zeros were calculated using the low frequency small signal model circuit as seen in handout P10 – figure 5a of the course notes 9 . The circuit was modelled using the 1/3 rd rule bias as shown in section 3.3. C π and C μ can estimated using the C IBO and C OBO values found in the datasheet 5 using V BE = 0.6 V and V BC = 5 V. These were determined to be as follows. C π = 18 pF C µ = 5 pF Using the OC and SC method discussed above, the low frequency poles and zeroes were calculated as shown below. ω LP 1 = 1 C C 1 ∗[ R ¿¿ S + [ R B 2 R B 1 ( r π + ( 1 + β ) R E ) ] ] ¿ ω LP 2 = 1 C C 2 ∗[ R L + R C ] ω LP 3 = 1 C E ¿¿ Y LZ 1 = sC C 1 Y LZ 1 = sC C 2 Y LZ 3 = 0 = 1 R E + sC E Elec 301 101: Mini Project 2 Page 9 of 26 Katie Seifert 68469311 2019-10-24
The Power of Trust. The Future of Energy. To begin, the high frequency poles and zeros were calculated using the high frequency small signal model circuit as seen in handout P10 – figure 5c of the course notes 3 . Using the OC and SC method discussed above, the high frequency poles and zeroes were calculated as shown below. ω HP 4 = 1 [ C ¿ ¿ π + C µ ( 1 + g m ( R L R C ) )]∗[ R S R B 1 R B 2 r π ] ¿ ω HP 5 = 1 C µ ∗[ R L R C ] ω HZ 4 = g m C µ Evaluation: Table 6 - Pole Locations and Comparisons ω Graphically determined Value Calculated Value Percent Error P 1L 383.1 mHz 377.98 mHz 1.35% P 2L 1.551 Hz 1.56 Hz 0.577% P 3L 627.5 Hz 632.86 Hz 0.847% P 4H 2.214 MHz 6.107 MHz 63.75% P 5H 17.78 MHz 15.603 MHz 13.95% Z 1L 0 Hz 0 Hz 0% Z 2L 0 Hz 0 Hz 0% Z 3L 4.516 Hz 3.7 Hz 22.05% Z 4H 1.212 GHz 1.273 GHz 4.79% Z 5H 10 GHz n/a While most graphically determined pole were within a reasonable margin of error, the transformation performed using the Miller gain created a large margin of error at ω P4H and a large margin of error overall for the high poles and zeroes due to its distortion in the high frequency range. This is not seen in the low frequency poles and they are therefore are much closer to the theoretical value. 4.2 Part B Simulation: From Figure 10 we can graphically determine the mid band frequency at 39.5 kHz, due to negative gain causing a phase shift from negative to positive at mid band. To determine the plot of the transfer curve, the circuit shown in Figure 8 was used, setting the frequency of the voltage source to the mid band frequency. The voltage amplitude was then varied, and the results of V o vs V s were plotted in as seen in Figure 12. Figure 10 – Phase Bode plot for 2N2222A (in rad/sec) Evaluation: Using the transfer curve plotted in Figure 12, we are able to graphically determine the linear break down point as being 60 mV. This is done by using the graph and determining the output voltage when the graph is no longer linear. 4.3 Part C Simulation: Using SPICE software, the circuit shown in Figure 8 – Tested circuit was simulated and the V in and I in were measured with the V s frequency set to the mid band frequency. From this, the Z in was calculated using ohm’s law and omitting the R s source resistance. The results are shown in Table 7. Elec 301 101: Mini Project 2 Page 10 of 26 Katie Seifert 68469311 2019-10-24
The Power of Trust. The Future of Energy. Calculations: The input impedance was calculated using the mid band circuit as shown in P10 – figure 5b of the course notes 9 . The calculation is shown below, and result is shown in Table 7. Z ¿ = R BB || r π Evaluation: Table 7 – Input Impedance Comparison Impedance Simulated Value Calculated Value Percent Error Z in 3.802 k Ω 3.811 k Ω 0.236% The percent error is such a small value that it can be considered negligible, therefore the theoretical value and the calculated value can be considered equal, therefore the mid band circuit model can be considered to be a highly accurate representation of the circuits mid band behaviour. 4.4 Part D Simulation: Using SPICE software, the circuit shown in Figure 8 – Tested circuit was simulated and the V out and I out were measured with the V s frequency set to the mid band frequency. From this, the Z out was calculated using ohm’s law and omitting the R L source resistance. The results are shown in Table 8. Calculations: The output impedance was calculated using the mid band circuit as shown in P10 – figure 5b of the course notes 9 . The calculation is shown below, and result is shown in Table 8. Z out = R C Evaluation: Table 8 – Output Impedance Comparison Impedance Simulated Value Calculated Value Percent Error Z out 5.0998 k Ω 5.1 k Ω 0.00392% The percent error is such a small value that it can be considered negligible, therefore the theoretical value and the calculated value can be considered equal, therefore the mid band circuit model can be considered to be a highly accurate representation of the circuits mid band behaviour. 4.5 Part E 4.5.1 2N3904 Simulation: Using SPICE software, the circuit shown in Figure 8 – Tested circuit was simulated and the Bode plots showing the magnitude and phase were noted in Figure 13 and Figure 14. Using the plots, we can graphically determine and confirm that the circuit is a band-pass filter. Following this, from Figure 14 we are able to graphically determine the mid band frequency at 80 kHz, due to negative gain causing a phase shift from negative to positive at mid band. To determine the plot of the transfer curve, the circuit shown in Figure 8 was used, setting the frequency of the voltage source to Elec 301 101: Mini Project 2 Page 11 of 26 Katie Seifert 68469311 2019-10-24
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The Power of Trust. The Future of Energy. the mid band frequency. The voltage amplitude was then varied, and the results of V o vs V s were plotted in as seen in Figure 15. Calculations: An example of the graphically determined poles is shown in Figure 11, demonstrating how poles were determined from the Bode plot of a simulated circuit. The graphically determined values are shown in Table 6 - Pole Locations. The values were determined by estimation, as the frequencies are located after the steepness of the slope begins to change. This was determined using estimation, as well as measurement and observation. The pole values were calculated using the Open Circuit and Short Circuit (OC and SC) method. In this method, all capacitors will act as open circuits before their pole frequency is reach, once their pole frequency has been passed, they then begin to act as short circuits. To calculate the frequency ω p , we first find the time constant τ . We do so by opening all capacitors with a lower value than the capacitor of interest and shorting all capacitors of a higher value, as well as the voltage source. From this, the equivalent resistance of the circuit seen by the capacitor of interest may be calculated and therefore we are able to calculate τ = RC . From this we can determine ω p = 1 τ . The zero are calculated similarly, determining at what value the admittance of a branch would be 0. To begin, the low frequency poles and zeros were calculated using the low frequency small signal model circuit as seen in handout P10 – figure 5a of the course notes 9 . The circuit was modelled using the 1/3 rd rule bias as shown in section 3.3. C π and C μ can estimated using the C IBO and C OBO values found in the datasheet 6 using V BE = 0.648 V and V BC = 5 V. These were determined to be as follows. C π = 3.6 pF C µ = 3 pF Using the OC and SC method discussed above, the low frequency poles and zeroes were calculated as shown below. Evaluation: Table 9 - Pole Locations and Comparisons ω Graphically determined Value Calculated Value Percent Error P 1L 403 mHz 387.92 mHz 3.89% P 2L 1.575 Hz 1.56 Hz 0.962% P 3L 634.8 Hz 634.859 Hz 0.00929 % P 4H 12.74 MHz 10.372 MHz 22.83% P 5H 19.47 MHz 20.8046 MHz 6.42% Z 1L 0 Hz 0 Hz 0% Z 2L 0 Hz 0 Hz 0% Z 3L 3.909 Hz 3.7 Hz 5.65% Z 4H 1.889 GHz 2.12207 MHz 10.98% Z 5H n/a While most graphically determined pole were within a reasonable margin of error, with some within a negligible amount due to the large resolution used in the simulation, the transformation performed using the Miller gain created a larger margin of error at ω P4H and a larger margin of error overall for the high poles and zeroes due to its distortion in the high frequency range. This is not seen in the low frequency poles and they are therefore are much closer to the theoretical value. Elec 301 101: Mini Project 2 Page 12 of 26 Katie Seifert 68469311 2019-10-24
The Power of Trust. The Future of Energy. Following this, using the transfer curve plotted in Figure 15 we are able to graphically determine the linear break down point as being 50 mV. This is done by using the graph and determining the output voltage when the graph is no longer linear. 4.5.2 2N4401 Simulation: Using SPICE software, the circuit shown in Figure 8 – Tested circuit was simulated and the Bode plots showing the magnitude and phase were noted in Figure 16 and Figure 17. Using the plots, we can graphically determine and confirm that the circuit is a band-pass filter. Following this, from Figure 17 we are able to graphically determine the mid band frequency at 48 kHz, due to negative gain causing a phase shift from negative to positive at mid band. To determine the plot of the transfer curve, the circuit shown in Figure 8 was used, setting the frequency of the voltage source to the mid band frequency. The voltage amplitude was then varied, and the results of V o vs V s were plotted in as seen in Figure 18. Calculations: An example of the graphically determined poles is shown in Figure 11, demonstrating how poles were determined from the Bode plot of a simulated circuit. The graphically determined values are shown in Table 10 - Pole Locations and Comparisons. The values were determined by estimation, as the frequencies are located after the steepness of the slope begins to change. This was determined using estimation, as well as measurement and observation. The pole values were calculated using the Open Circuit and Short Circuit (OC and SC) method. In this method, all capacitors will act as open circuits before their pole frequency is reach, once their pole frequency has been passed, they then begin to act as short circuits. To calculate the frequency ω p , we first find the time constant τ . We do so by opening all capacitors with a lower value than the capacitor of interest and shorting all capacitors of a higher value, as well as the voltage source. From this, the equivalent resistance of the circuit seen by the capacitor of interest may be calculated and therefore we are able to calculate τ = RC . From this we can determine ω p = 1 τ . The zero are calculated similarly, determining at what value the admittance of a branch would be 0. To begin, the low frequency poles and zeros were calculated using the low frequency small signal model circuit as seen in handout P10 – figure 5a of the course notes 9 . The circuit was modelled using the 1/3 rd rule bias as shown in section 3.3. C π and C μ can estimated using the C IBO and C OBO values found in the datasheet 7 using V BE = 0.659 V and V BC = 5 V. These were determined to be as follows. C π = 19.5 pF C µ = 7.9 pF Using the OC and SC method discussed above, the low frequency poles and zeroes were calculated as shown below. Elec 301 101: Mini Project 2 Page 13 of 26 Katie Seifert 68469311 2019-10-24
The Power of Trust. The Future of Energy. Evaluation: Table 10 - Pole Locations and Comparisons ω Graphically determined Value Calculated Value Percent Error P 1L 379.3 mHz 381.6 mHz 0.602% P 2L 1.547 Hz 1.56 Hz 0.833% P 3L 631.0 Hz 635.936 Hz 0.776% P 4H 4.079 MHz 4.061128 MHz 0.44% P 5H 7.122 MHz 7.9005 MHz 9.85% Z 1L 0 Hz 0 Hz 0% Z 2L 0 Hz 0 Hz 0% Z 3L 3.793 Hz 3.7 Hz 2.51% Z 4H 0.804 GHz 0.80585 GHz 0.229% Z 5H 32.01 GHz n/a While most graphically determined pole were within a reasonable margin of error, with some within a negligible amount due to the large resolution used in the simulation, the transformation performed using the Miller gain created a larger margin of error at ω P5H and a larger margin of error overall for the high poles and zeroes due to its distortion in the high frequency range. This is not seen in the low frequency poles and they are therefore are much closer to the theoretical value. Following this, using the transfer curve plotted in Figure 18, we are able to graphically determine the linear break down point as being 50 mV. This is done by using the graph and determining the output voltage when the graph is no longer linear. 4.5.3 Transistor Comparison Each transistor would offer different benefits depending on it’s use case. For example, the 2N2222A has the smallest pass band, meaning that the transistor would give the best performance if the use case required a very limited amount of frequencies to pass through. Similarly, the 2N4401 has the largest pass band, allowing for the largest range of frequencies to pass through. Therefore, there is not one transistor that gives the best performance, as it depends on what it will be required to perform within the circuit or amplifier it is placed in. Elec 301 101: Mini Project 2 Page 14 of 26 Katie Seifert 68469311 2019-10-24
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The Power of Trust. The Future of Energy. 5 PART 3 – COMMON BASE AMPLIFIER SIMULATION 5.1 Part A Simulation: Using SPICE software, the circuit shown in Figure 19 was simulated and the Bode plots showing the magnitude and phase were noted in Figure 20 and Figure 21. Using the plots, we can graphically determine and confirm that the circuit is a band-pass filter. Calculations: An example of the graphically determined poles is shown in Figure 11, demonstrating how poles were determined from the Bode plot of a simulated circuit. The graphically determined values are shown in Table 11 - Pole Locations and Comparisons. The values were determined by estimation, as the frequencies are located after the steepness of the slope begins to change. This was determined using estimation, as well as measurement and observation. The pole values were calculated using the Open Circuit and Short Circuit (OC and SC) method. In this method, all capacitors will act as open circuits before their pole frequency is reach, once their pole frequency has been passed, they then begin to act as short circuits. To calculate the frequency ω p , we first find the time constant τ . We do so by opening all capacitors with a lower value than the capacitor of interest and shorting all capacitors of a higher value, as well as the voltage source. From this, the equivalent resistance of the circuit seen by the capacitor of interest may be calculated and therefore we are able to calculate τ = RC . From this we can determine ω p = 1 τ . The zero are calculated similarly, determining at what value the admittance of a branch would be 0. Evaluation: Table 11 - Pole Locations and Comparisons ω Graphically determined Value Calculated Value Percent Error P 1L 1.547 Hz 1.56 Hz 0.833% P 2L 1.624 Hz 1.634 Hz 0.612% P 3L 63.1 Hz 63.363 Hz 0.415% P 4H 12.44 MHz 12.483 MHz 0.345% P 5H 532.5 MHz 534.7 MHz 0.411% Z 1L 0 Hz 0 Hz 0% Z 2L 0 Hz 0 Hz 0% Z 3L 361.3 m Hz 356.5 m Hz 1.35% Z 4H n/a Z 5H n/a While most graphically determined pole were within a reasonable margin of error, with some within a negligible amount due to the large resolution used in the simulation, the ω z3L had a comparably large margin of error, due to its location within the plot and the relative difficulty graphically determining it’s value. 5.2 Part B Simulation: From Figure 22 we can graphically determine the mid band frequency at 67.9 kHz, due to negative gain causing a phase shift from negative to positive at mid band. To determine the plot of the transfer curve, Elec 301 101: Mini Project 2 Page 15 of 26 Katie Seifert 68469311 2019-10-24
The Power of Trust. The Future of Energy. the circuit shown in Figure 19 was used, setting the frequency of the voltage source to the mid band frequency. The voltage amplitude was then varied, and the results of V o vs V s were plotted in as seen in Figure 22. Evaluation: Using the transfer curve plotted in Figure 22, we can graphically determine the linear break down point as being 110 mV. This is done by using the graph and determining the output voltage when the graph is no longer linear. 5.3 Part C Simulation: Using SPICE software, the circuit shown in Figure 19 was simulated and the V in and I in were measured with the V s frequency set to the mid band frequency. From this, the Z in was calculated using ohm’s law and omitting the R s source resistance. The results are shown in Table 12 – Input Impedance Comparison. Calculations: The input impedance was calculated using the mid band circuit. The calculation is shown below, and result is shown in Table 12. Z ¿ = ¿¿ Evaluation: Table 12 – Input Impedance Comparison Impedance Simulated Value Calculated Value Percent Error Z in 28.2889 24.708 14.5% The percent error is within a reasonable limit, as most common resistors are made to be within a ±10% error margin. It is therefore reasonable to conclude that the mid band circuit model to be considered to be an accurate representation of the circuits mid band behaviour. 5.4 Part D Simulation: Using SPICE software, the circuit shown in Figure 19 was simulated and the V out and I out were measured with the V s frequency set to the mid band frequency. From this, the Z out was calculated using ohm’s law and omitting the R L source resistance. The results are shown in Table 13. Calculations: The output impedance was calculated using the mid band circuit. The calculation is shown below, and result is shown in Table 13. Z out = R C Evaluation: Table 13 – Output Impedance Comparison Impedance Simulated Value Calculated Value Percent Error Z out 5.0996 k Ω 5.1 k Ω 0.00784% Elec 301 101: Mini Project 2 Page 16 of 26 Katie Seifert 68469311 2019-10-24
The Power of Trust. The Future of Energy. The percent error is such a small value that it can be considered negligible, therefore the theoretical value and the calculated value can be considered equal, therefore the mid band circuit model can be considered to be a highly accurate representation of the circuits mid band behaviour. APPENDIX A: COMMON EMITTER MODELLING AND BIASING TEST DATA Figure 1 - I b vs V be with I b as variable parameter tested circuit Figure 2 – I B vs V BE with I B as variable parameter waveform Figure 3 – I C vs V CE with I B as variable parameter tested circuit Elec 301 101: Mini Project 2 Page 17 of 26 Katie Seifert 68469311 2019-10-24
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The Power of Trust. The Future of Energy. Figure 4 – I C vs V CE with I B as variable parameter waveform Figure 5 – I C vs V CE with V BE as variable parameter tested circuit Figure 6 – I C vs V CE with V BE as variable parameter waveform Figure 7 – Tested circuit Elec 301 101: Mini Project 2 Page 18 of 26 Katie Seifert 68469311 2019-10-24
The Power of Trust. The Future of Energy. APPENDIX B: COMMON EMITTER AMPLIFIER SIMULATION TEST DATA Figure 8 – Tested circuit Figure 9 – Magnitude Bode plot for 2N2222A (in DB) Figure 10 – Phase Bode plot for 2N2222A (in rad/sec) Elec 301 101: Mini Project 2 Page 19 of 26 Katie Seifert 68469311 2019-10-24
The Power of Trust. The Future of Energy. Figure 11 – Example of graphical pole determination 0.03 0.05 0.08 0.1 0.13 0.15 0.18 0.2 0.25 0.5 0.75 1 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 Transfer Curve (Vo/Vs) @ 39.5 kHz Vs (in V) Vo (in V) Figure 12 – Transfer curve (V o /V s ) for 2N2222A graph Elec 301 101: Mini Project 2 Page 20 of 26 Katie Seifert 68469311 2019-10-24
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The Power of Trust. The Future of Energy. Figure 13 – Magnitude Bode plot for 2N3904 (in DB) Figure 14 – Phase Bode plot for 2N3904 (in rad/sec) 0.03 0.05 0.1 0.13 0.15 0.18 0.2 0.25 0.5 1 0 0.5 1 1.5 2 2.5 3 3.5 Transfer Curve (Vo/Vs) @ 80 kHz Vs (in V) Vo (in V) Figure 15 – Transfer curve (V o /V s ) for 2N3904 graph Elec 301 101: Mini Project 2 Page 21 of 26 Katie Seifert 68469311 2019-10-24
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The Power of Trust. The Future of Energy. Figure 16 – Magnitude Bode plot for 2N4401 (in DB) Figure 17 – Phase Bode plot for 2N4401 (in rad/sec) 0.03 0.05 0.08 0.1 0.13 0.15 0.18 0.2 0.25 0.5 0.75 1 0 0.5 1 1.5 2 2.5 3 3.5 4 Transfer Curve (Vo/Vs) @ 48 kHz Vs (in V) Vo (in V) Figure 18 – Transfer curve (V o /V s ) for 2N4401 graph Elec 301 101: Mini Project 2 Page 22 of 26 Katie Seifert 68469311 2019-10-24
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The Power of Trust. The Future of Energy. APPENDIX C: COMMON BASE ACOMPLIFIER SIMULATION TEST DATA Figure 19 – Tested circuit Figure 20 – Magnitude Bode plot for 2N2222A (in DB) Figure 21 – Phase Bode plot for 2N2222A (in rad/sec) Elec 301 101: Mini Project 2 Page 23 of 26 Katie Seifert 68469311 2019-10-24
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The Power of Trust. The Future of Energy. 0 0.2 0.4 0.6 0.8 1 1.2 0 0.5 1 1.5 2 2.5 Transfer Curve (Vo/Vs) @ 67.9 kHz Vs (in V) Vo (in V) Figure 22 – Transfer curve (V o /V s ) for 2N2222A graph Elec 301 101: Mini Project 2 Page 24 of 26 Katie Seifert 68469311 2019-10-24
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The Power of Trust. The Future of Energy. APPENDIX D: REFERENCES 1. ELEC 301 Course Notes 2. A. Sedra and K. Smith, "Microelectronic Circuits," 5 th (or higher) Ed., Oxford University Press, New York 3. Standard Values List http://ecee.colorado.edu/~mcclurel/resistorsandcaps.pdf 4. 2N2222A ON Semiconductor datasheet http://web.mit.edu/6.101/www/reference/2N2222A.pdf? fbclid=IwAR0O8VHMSLVdlZ_bdDbGrQ60LX412Vmv173vXmDQZ8fgfcfGL6pO4TA5868 5. 2N2222A ST microelectronics https://www.st.com/resource/en/datasheet/cd00003223.pdf 6. 2N3904 ON Semiconductor datasheet https://www.onsemi.com/pub/Collateral/2N3903-D.PDF 7. 2N4401 ON Semiconductor datasheet https://www.onsemi.com/pub/Collateral/2N4401-D.PDF 8. CircuitMaker™ (or other circuit simulator) User’s Manual 9. Notes on CANVAS Elec 301 101: Mini Project 2 Page 25 of 26 Katie Seifert 68469311 2019-10-24
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