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test-and-measurement:analog-discovery-pro-5250:transistor-tester [2022/01/13 09:04] – [Writing the Script] Álmos Veres-Vitályostest-and-measurement:analog-discovery-pro-5250:transistor-tester [2022/10/04 11:38] (current) – external edit 127.0.0.1
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   * [[test-and-measurement:analog-discovery-pro-5250:start|]]   * [[test-and-measurement:analog-discovery-pro-5250:start|]]
   * [[https://www.diodes.com/assets/Datasheets/ZVN3310A.pdf|ZVN3310A]], or other transistor   * [[https://www.diodes.com/assets/Datasheets/ZVN3310A.pdf|ZVN3310A]], or other transistor
-  * 2x 10W 100Ω ceramic resistors+  * 2x 10W 51Ω ceramic resistors
  
 === Software === === Software ===
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 In this test, the drain current versus the drain-source voltage of the selected MOSFET will be plotted for varying gate-source voltages. Connect the gate of the transistor to the waveform generator and the source to the ground. In this test, the drain current versus the drain-source voltage of the selected MOSFET will be plotted for varying gate-source voltages. Connect the gate of the transistor to the waveform generator and the source to the ground.
  
-To limit the maximum drain current, a 50Ω resistor is needed in series with the transistor. The maximum output current of the ADP5250 on the +25V supply is 500mA, so the maximum power dissipated by the resistor, in the case of an ideal switch instead of the MOSFET (with 0Ω resistance), would be $P_{R}={I_{R}}^{2}*R={(0.5A)}^{2}*50Ω=(0.25*50)W=12.5W$ which is higher then the rated power of the 10W ceramic resistors so two pieces of 100Ω resistors will be used in parallel (the current is divided equally between them, so the dissipated power will be only half, which is 6.25W, below 10W).+To limit the maximum drain current to the maximum output current of the supplies, a $R=\frac{V}{I}=\frac{V_{+}-V_{-}}{I}=\frac{25V+25V}{0.5A}=100Ω$ resistor is needed in series with the transistor. 
 + 
 +The maximum output current of the ADP5250 on the +25V and -25V supplies is 500mA, so the maximum power dissipated by the resistor, in the case of an ideal switch instead of the MOSFET (with 0Ω resistance), would be $P_{R}=I_{Rmax}*V_{Rmax}=0.5A*50V=25W$ which is higher then the rated power of the 10W ceramic resistors. To protect the circuit, two pieces of 51Ω resistors will be used in series, so the voltage is divided equally between them, the dissipated power being only half, which is 12.5W. This is still above 10W so the maximum voltage should also be reduced. If the maximum voltage drop is only 40V, the dissipated power by the resistors will be $P_{51R}=\frac{I_{Rmax}*V_{Rmax}}{2}=\frac{0.5*40V}{2}=10W$
 </WRAP><WRAP half column> </WRAP><WRAP half column>
-{{ :test-and-measurement:analog-discovery-pro-5250:transistor_tester_sc.png?600 |}}+{{ :test-and-measurement:analog-discovery-pro-5250:transistor_tester_sch.png?600 |}}
 </WRAP></WRAP> </WRAP></WRAP>
  
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 </WRAP> </WRAP>
 </WRAP><WRAP half column> </WRAP><WRAP half column>
-{{ :test-and-measurement:analog-discovery-pro-5250:transistor_tester_bb.png?600 |}}+{{ :test-and-measurement:analog-discovery-pro-5250:transistor_tester_bbd.png?600 |}}
 </WRAP></WRAP> </WRAP></WRAP>
 ---- ----
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 ===== Writing the Script ===== ===== Writing the Script =====
 <WRAP group> <WRAP group>
-The full script can be downloaded {{|here}}.+The full script can be downloaded {{ :test-and-measurement:analog-discovery-pro-5250:transistor.zip |here}}.
 </WRAP> </WRAP>
  
 <WRAP group><WRAP half column> <WRAP group><WRAP half column>
 +Import the necessary packages into your script and define the measurement parameters.
 </WRAP><WRAP half column><code python> </WRAP><WRAP half column><code python>
 from WF_SDK import device, supplies, wavegen, dmm # import instruments from WF_SDK import device, supplies, wavegen, dmm # import instruments
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 # parameters # parameters
 Vd_resolution = 500 # drain voltage resolution in mV Vd_resolution = 500 # drain voltage resolution in mV
-Vd_limit = 25       # maximum drain voltage in V+Vd_limit = 40       # maximum drain voltage in V
 Vg_resolution = 2   # gate voltage resolution in V Vg_resolution = 2   # gate voltage resolution in V
 Vg_limit = 12       # maximum gate voltage in V Vg_limit = 12       # maximum gate voltage in V
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 <WRAP group><WRAP half column> <WRAP group><WRAP half column>
 +Connect to the device, initialize the digital multimeter and generate the lists of voltages which will be generated in the following. Also create empty lists for the results.
 </WRAP><WRAP half column><code python> </WRAP><WRAP half column><code python>
 # connect to the device # connect to the device
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 <WRAP group><WRAP half column> <WRAP group><WRAP half column>
 +Step through the list of gate-source voltages. Output every voltage on the waveform generator.
  
 +For every gate-source voltage, step through the list of drain voltages, outputting each on the +25V supply. After the voltage change is commanded, wait a bit for the supply voltage to settle, then use the digital multimeter to measure the drain-source voltage and the drain current. Don't forget to invert the voltage.
 </WRAP><WRAP half column><code python> </WRAP><WRAP half column><code python>
 try: try:
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             print("\tDrain voltage: " + str(drain_voltage) + "V")             print("\tDrain voltage: " + str(drain_voltage) + "V")
             # set the drain voltage             # set the drain voltage
-            supplies.switch_25V(device_handle, True, False, drain_voltage, 0)+            if drain_voltage > 25: 
 +                supplies.switch_25V(device_handle, True, True, drain_voltage - 25, -25) 
 +            else: 
 +                supplies.switch_25V(device_handle, True, True, 0, drain_voltage * (-1))
  
             # delay             # delay
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 <WRAP group><WRAP half column> <WRAP group><WRAP half column>
 +When the measurement is finished, close every instrument and disconnect from the device.
 </WRAP><WRAP half column><code python> </WRAP><WRAP half column><code python>
 # reset the scope # reset the scope
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 <WRAP group><WRAP half column> <WRAP group><WRAP half column>
 +Finally, plot the results.
 </WRAP><WRAP half column><code python> </WRAP><WRAP half column><code python>
 # plot results # plot results
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 ===== Testing ===== ===== Testing =====
 <WRAP group><WRAP half column> <WRAP group><WRAP half column>
 +Turn on the ADP5250 and start the script. Wait for it to finish. You can save the plotted results by clicking on the respective button. Compare your results to the one presented in the datasheet of the transistor.
  
-</WRAP><WRAP half column>+<WRAP center round important 80%> 
 +The resistors and the MOSFET might get hot! Don't let the setup unsupervised!!! 
 +</WRAP>
  
 +</WRAP><WRAP half column>
 +{{ :test-and-measurement:analog-discovery-pro-5250:output_zvn3310a.png?600 |}}
 </WRAP></WRAP> </WRAP></WRAP>
 ---- ----