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university:courses:alm1k:alm-lab-4 [08 Jan 2018 16:06] – add beta vs Vce plot Doug Mercer | university:courses:alm1k:alm-lab-4 [02 Feb 2023 20:37] (current) – add example I/V curve Doug Mercer |
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======Activity 4: BJT Characteristic Curves ====== | ======Activity: BJT Characteristic Curves, For ADALM1000====== |
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=====Objective:===== | =====Objective:===== |
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The 0.4 V steps in the voltage driving the 10 KΩ base resistor will produce approximately 0.4 V/10 KΩ or 40 uA steps in the base current. Using the scope in XY mode plot channel CA-V on the horizontal axis (V<sub>CE</sub>) and channel CA-I (I<sub>C</sub>) on the vertical axis. You should see a set of 10 curves of I<sub>C</sub> vs. V<sub>CE</sub>, one for each of the 10 different base current levels. These base current levels should be approximately 0, 40uA, 80uA, 120uA ... 360uA. It may be necessary to slightly adjust the 0.6V offset level of the first step of channel B up or down slightly to insure it is right at the initial turn on value ( I<sub>B</sub>=0 and I<sub>C</sub>=0) of the transistor you are testing. | The 0.4 V steps in the voltage driving the 10 KΩ base resistor will produce approximately 0.4 V/10 KΩ or 40 uA steps in the base current. Using the scope in XY mode plot channel CA-V on the horizontal axis (V<sub>CE</sub>) and channel CA-I (I<sub>C</sub>) on the vertical axis. You should see a set of 10 curves of I<sub>C</sub> vs. V<sub>CE</sub>, one for each of the 10 different base current levels. These base current levels should be approximately 0, 40uA, 80uA, 120uA ... 360uA. It may be necessary to slightly adjust the 0.6V offset level of the first step of channel B up or down slightly to insure it is right at the initial turn on value ( I<sub>B</sub>=0 and I<sub>C</sub>=0) of the transistor you are testing. |
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| {{ :university:courses:alm1k:alm_lab4_f5.png?400 |}} |
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| <WRAP centeralign>Figure 1A, Example NPN I<sub>C</sub> vs. V<sub>CE</sub> characteristic curves.</WRAP> |
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====Questions:==== | ====Questions:==== |
{{ :university:courses:alm1k:alm_lab4_f2.png?600 |}} | {{ :university:courses:alm1k:alm_lab4_f2.png?600 |}} |
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<WRAP centeralign>Figure 2 PNP I<sub>C</sub> vs. V<sub>CE</sub> characteristic curve measurments</WRAP> | <WRAP centeralign>Figure 2 PNP I<sub>C</sub> vs. V<sub>CE</sub> characteristic curve measurements</WRAP> |
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====NPN Beta vs Collector Voltage Directions:==== | ====NPN Beta vs Collector Voltage Directions:==== |
Calculate the Beta Early voltage product ( ß*VA) for each device.\\ | Calculate the Beta Early voltage product ( ß*VA) for each device.\\ |
Compare your results with manufacturer specifications for each device measured. | Compare your results with manufacturer specifications for each device measured. |
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| **Resources:** |
| * LTSpice files: [[downgit>education_tools/tree/master/m1k/ltspice/bjt_char_curves_ltspice | bjt_char_curves_ltspice]] |
| * Fritzing files: [[downgit>education_tools/tree/master/m1k/fritzing/bjt_char_curves_bb | bjt_char_curves_bb]] |
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**For Further Reading:** | **For Further Reading:** |
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http://en.wikipedia.org/wiki/Bipolar_junction_transistor\\ | [[wp>Bipolar_junction_transistor|Bipolar junction transistor]]\\ |
http://www.physics.csbsju.edu/trace/NPN.CC.html | http://www.physics.csbsju.edu/trace/NPN.CC.html |
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**Return to ALM Lab Activity [[university:courses:alm1k:alm-labs-list|Table of Contents]]** | **Return to ALM Lab Activity [[university:courses:alm1k:alm-labs-list|Table of Contents]]** |
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