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| university:courses:electronics:electronics-lab-4 [05 Mar 2019 11:04] – [Alternative Method] Antoniu Miclaus | university:courses:electronics:electronics-lab-4 [12 Jul 2019 12:49] – [Activity 4. A BJT Curve Tracer] Pop Andreea |
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| ====== Activity 4. A BJT Curve Tracer ====== | ====== Activity: A BJT Curve Tracer ====== |
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| ===== Objective: ===== | ===== Objective: ===== |
| ===== Directions and Setup: ===== | ===== Directions and Setup: ===== |
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| Build the simple curve tracer circuit shown in figure 1. The green boxes indicate where to connect the ADALM2000. Using the custom waveform editor in the Scopy AWG tool, construct a stair-step waveform with 5 levels. Be sure to reset so that you are starting with flat line at 0%. First set the type to constant. Then with start set to 0%, length set to 20% and offset set to -100% click on generate function. There should now be a line at -100% from 0 to 20%. Next change the start to 20% and the offset to -50% and then click on generate function again. There should now be a line at -50% from 20% to 40%. Next set the offset to +50% and the start to 60% and then click on generate function again. There should now be a line at 0% from 40% to 60% and a line at 50% from 60% to 80%. Finally set the offset to 100% and start to 80% and click on generate function one last time. There should now be a final line at 100% from 80% to 100%. Click on save and your new waveform should be in channel 2. Now at this point set the frequency to 40Hz, the amplitude to 2 V and the offset to 2.6 V. The waveform in the display should start at 0.6V and increase in 1 V increments to 4.6 V (0.6, 1.6, 2.6, 3.6, 4.6) Each step should be 5 mSec long for a total of 25 mSec. In AWG channel 1 configure a triangle wave with an amplitude of 2.5 V and an offset of 2.5V (wave should swing from 0 to 5V). Set the frequency to 200 Hz ( 5 times the 40 Hz of channel 2). Comparing the waveforms in channel 1 and channel 2, the triangle wave in channel 1 should go through one cycle from 0 to 5 V and back to zero during the time of one step in the waveform in channel 2. It will probably be necessary to set the phase of channel 1 to 90 degrees to make them line up in this way. | Build the simple curve tracer circuit shown in Figure 1. The green boxes indicate where to connect the ADALM2000. Using the Scopy Signal Generator tool, in Channel 2 Buffer tab import the csv file for the stairstep signal needed. |
| | Now at this point set the amplitude to 2 V and the offset to 2.6 V. The waveform in the display should start at 0.6V and increase in 1 V increments to 4.6 V (0.6, 1.6, 2.6, 3.6, 4.6). For each step to be 5 mSec long for a total of 25 mSec, set the sampling rate 200 Hz. |
| | In Signal Generator Channel 1 configure a triangle wave with an amplitude of 5V and an offset of 2.5V (wave should swing from 0 to 5V). Set the frequency to 200 Hz ( 5 times the 40 Hz of channel 2). Comparing the waveforms in Channel 1 and Channel 2, the triangle wave in Channel 1 should go through one cycle from 0 to 5 V and back to zero during the time of one step in the waveform in Channel 2. It will probably be necessary to set the phase of Channel 1 to 90 degrees to make them line up in this way. |
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| You should export your newly created stair-step waveform to a .csv file for future use. | |
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| ===== Procedure: ===== | ===== Procedure: ===== |
| * Fritzing files: [[ https://minhaskamal.github.io/DownGit/#/home?url=https://github.com/analogdevicesinc/education_tools/tree/master/m2k/fritzing/bjt_curve_bb | bjt_curve_bb]] | * Fritzing files: [[ https://minhaskamal.github.io/DownGit/#/home?url=https://github.com/analogdevicesinc/education_tools/tree/master/m2k/fritzing/bjt_curve_bb | bjt_curve_bb]] |
| * LTSpice files: [[ https://minhaskamal.github.io/DownGit/#/home?url=https://github.com/analogdevicesinc/education_tools/tree/master/m2k/ltspice/bjt_curve_ltspice | bjt_curve_ltspice]] | * LTSpice files: [[ https://minhaskamal.github.io/DownGit/#/home?url=https://github.com/analogdevicesinc/education_tools/tree/master/m2k/ltspice/bjt_curve_ltspice | bjt_curve_ltspice]] |
| | * Stairstep signal: [[ https://minhaskamal.github.io/DownGit/#/home?url=https://github.com/analogdevicesinc/education_tools/blob/master/m2k/import_waveforms/waveforms_sg/stairstep.csv | stairstep]] |
| </WRAP> | </WRAP> |
| ==== For further reading on the Howland current source: ==== | ==== For further reading on the Howland current source: ==== |
