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 **BJT Curve Tracer 9000**

=1. Design and Teamwork Report=

A. BJT Curve Tracer 9000
Group #3 Ka Siu  Wesley Nguyen  Chris Nguyen 

B. Design Idea Objective
The BJT Curve Tracer 9000 gives the Ic vs. Vce and Beta vs. Ic characteristic curves for the MPSA56 family of PNP transistors and the MPSA06 family of NPN transistors used in the EE348 Lab at Cal Poly San Luis Obispo.

D.Design Process
The following phases depict the different iterations that took place in the design process. As problems and realizations occur during testing and designing, updates of customer requirements and specifications change accordingly. We kept in mind throughout our design process of the customer requirements as we attempted to met their needs. As interviews and research were done, we changed our design idea objective to meet a more realistic goal meeting the deadline of June 6, 2011as well as satisfying customer needs.

__**Phase 1: Initial Design**__ In preparation for Design Review 1, the initial goal consisted of characterizations of various components: Diodes, BJTs, and MOSFETs. Given the correct setup parameters, the LabView program will offer 3 different types of curves for 5 different circuit components. The program will be able to characterize any BJT (npn or pnp), MOSFET (PMOS or NMOS), or Diode. Given the part number of the chip, the user will be able to analyze and compare the ac

-Use a curve tracer technique to acquire the characterization of Diodes/BJTs/MOSFETs -Design a user friendly test circuit setup compatible with all expected components -Ensures validity of transistors in quick and efficient manner -Diodes: Obtain Id vs. Vd Curves -BJTs: Obtain Ic vs. Vce Curves -MOSFETS: Obtain Id vs. Vds Curves
 * Requirements**

-Ensure the design works for all desired test components -Verify our test results within +/- 5% of the datasheet values -Include current and voltage limiting parameters corresponding to component datasheets -Fit front panel and wiring diagrams to one screen -Use the Agilent E3640 DC Power Supply and Agilent 34401A Digital Multimeter
 * Specifications**



__**Phase 2: First Revision**__ Research of various Diodes, BJTsand MOSFETS proved the projects initial goals to be too optimistic. Due to the various types of components and their variations in specifications from the datasheet values, i.e. maximum output voltages and currents and characterization curves, we have decided to focus our goals on a single transistor family.

-User friendly test system. -Use a curve tracer technique to acquire the Ic vs. Vce characterization curves of the specified BJT transistors. -Include BJT Terminal Specifications to distinguish which BJT types are being tested. -Create a test system that will be reusable for all EE438 labs.
 * Requirements**

-Ensure the design works for the MPSA56 family of PNP and the MPSA06 family of NPN transistors. This includes current and voltage limitations -Plot the Ic-V Characteristic -Find the Early Voltage Value -Plot the Beta-Ic Characteristic -Fit front panel to one screen. -Utilize the following equipment for curve characterization HP E3640A DC Power Supply Agilent 34401A Digit Multimeter Keithley 2400 SourceMeter
 * Specifications**





__**Phase 3: Second Revision**__ After speaking with customers, further definitions of user specifications include reducing the tests to only the npn and pnp characterizations. BJT Terminal specifications has been disregarded since indicators of the type of BJT as well as their terminals can be determined from their datasheet. To simplify the labview vi, both characterizations for I-V curves are placed on one tab as opposed to two different ones. Similarly, the Beta vs. Ic tab includes both NPN and PNP BJTs.

-User friendly test system. -Use a curve tracer technique to acquire the Ic vs. Vce characterization curves of the specified BJT transistors. -Obtain Beta vs. Ic Characterization curves of specified BJT transistors. -Create a test system that will be reusable for all EE438 labs.
 * Requirements**

-Ensure the design works for the MPSA56 family of PNP and the MPSA06 family of NPN transistors. This includes current and voltage limitations -Plot the Ic-V Characteristic -Find the Early Voltage Value -Plot the Beta-Ic Characteristic -Utilize the following equipment for curve characterization HP E3640A DC Power Supply Agilent 34401A Digit Multimeter Keithley 2400 SourceMeter
 * Specifications**

__**Phase 4: Final Revisions**__ Final Revision and proposal include fully working curves for the 2 different families of BJTs as well as instructions on the front panel in testing the circuits. User controls were altered so that the user is unable to fry or burn the circuit by setting too high voltages. Circuit diagrams are updated so that the the collector, base, and emitter nodes are labeled as well as the polarity of the equipment setup. Additionally, the customer will be able to save data to a file.

-User friendly test system. -Use a curve tracer technique to acquire the Ic vs. Vce characterization curves of the specified BJT transistors. -Obtain Beta vs. Ic Characterization curves of specified BJT transistors. -Option to create a save file in xml format so data can be saved. -Annotated circuit diagrams so user can setup circuit -Create a test system that will be reusable for all EE438 labs.
 * Requirements**

-Ensure the design works for the MPSA56 family of PNP and the MPSA06 family of NPN transistors. This includes current and voltage limitations -Plot the Ic-V Characteristic -User inputs: Pick transistor type, Vce Step Size, Number of Data points, Number of Curves, and Base Current Step Size -Find the Early Voltage Value -Plot the Beta-Ic Characteristic -Vce voltage, number of data points -Fit front panel and wiring diagrams to one screen. -Utilize the following equipment for curve characterization HP E3640A DC Power Supply Agilent 34401A Digit Multimeter Keithley 2400 SourceMeter Topward Dual-Tracking DC Power Supply
 * Specifications**







=2. BJT Curve Tracer 9000 Sustainability Analysis=

A. BJT Curve Tracer's Applications Towards Sustainability
The automated BJT Curve Tracer 9000 provides a test system for students to verify Experiment A of the EE348 Lab, which is an experiment to test the BJT transistors used throughout the class. The BJT Curve Tracer 9000 is designed specifically for Experiment A, which provides a user friendly interface. This project decreases the number of chips wasted by reducing the number of transistors that may be overloaded or frying during this experiment. This project, which sets the current and voltage limits, reduces the possibility of frying transistors. The BJT Curve Tracer is an automated test system which allows for fast characterization. This curve tracer is different from the antique curve tracers, because the test system has minimal hardware components. The software is designed to be modular, allowing for code alterations if the system needs to be upgraded. A primarily software oriented approach what contains modularity is a benefit over hardware approaches of curve tracer designes, because hardware is difficult to upgrade. The benefits of a modular test system which allow for simple modification, so time and money don’t need to be wasted to create entirely new test systems for different chips.

B. Four E's of Sustainability

 * 1) **Ecology -**The BJT Curve Tracer 9000 test system requires very minimal hardware components. The design of the ExpressPCB board is optional, and without it the students will need the BJT transistors required for the class, two 1kOhm resistors, and the reusable leads that students can check out from the senior project lab. A computer with LabView 8.6 software and access to the proper measurement equipment will also be provided by the school lab rooms 146 - 149.
 * 2) **Energy -** The BJT Curve Tracer 9000 requires the energy to power the computers in lab and the measurement equipment. The Topward DC Power Supply is expected to supply up to 10V, the Agilent DC Power Supply is expected to supply up to 10V, and the Keithly Source Meter is expected to supply less than 1mAmp**.** The Agilent Multimeter, PC, and all other equipment attached to the GPIB bus draws all the energy it needs to stay on and functional.
 * 3) **Economy -** The EE students and professors at Cal Poly directly benefit from this project by having access to a fast, efficient, and easy to use test system for Experiment A of the EE348 Lab. The cost of the instruments, leads, and computers are included and provided to the students through the donations or purchases made for the EE department, and the cost for the students is the cost of the EE438 Lab Kit, which currently costs $27.95. [1] The students benefit from the project by reducing the amount of time required to run the tests, and saving money by reducing the number of additional transistors to purchase. This experiment can be put into effect starting fall quarter of 2011. The BJT Curve Tracer 9000 can exist as long as there is a need for Cal Poly EE348 students to characterize their BJTs, and the maintenance cost is for the school to continue to support LabView 8.6.
 * 4) **Equity -** The BJT Curve Tracer 9000 directly impacts the students and professors of the EE348 Lab, by providing an additional program to execute Experiment A. The students and professors benefit from this project free of charge, and this project is based primarily for academic purposes.

C. Green Engineering Design Principles
> BJT Curve Tracer 9000 is designed to ease Cal Poly students into the EE348 Lab Course as aids the user in completion of successfully characterizing BJTs in a safe manner. > > By reducing amount of extra BJTs bought at Cal Poly's EE348 Lab class due to overloading and frying out old chips, there will be less electronic waste products going out into the environment. > > Project includes features that can eventually be altered in later versions that allow for various families of BJTs to be characterized and not just specific MPSA06 and MPSA56 families. > > The circuits designed to implement the labview program were designed to have the minimal number of components necessary to accomplish the desired task. Nodes and labels are placed in the PCB layout to facilitate user's circuit setup. > > Circuit design of PCB layout, if printed, ensures that circuit setups for various stages of laboratory exercise can not be setup correctly. Less resources will be used in ordering additional parts that require manufacturing using natural resources. > > Labview program strives to prevent waste through use of implemented current and voltage limits. This way, users will not be able to burn the BJTs during their exercises. > > As BJTs are used throughout the electronics industry in creation of many products, the labview program acts as a tutor for students currently learning characteristics of this component in various EE courses over the world. > > By acting as a curve tracer, this cheaper method of characterizing BJTs can get rid of old bulky equipment currently kept idle at Cal Poly's Electrical Engineering Lab Rooms. This design saves money and space with the ability to be updated at a later time if needed. > > Proposed to work in the EE348 lab environment, the BJT Curve Tracer 9000 demonstrates the use of an automated test system to give quick and efficient solutions in characterizing circuit diagrams.
 * 1) Engineer processes and products holistically, use systems analysis, and integrate environmental impact assessment tools..
 * 1) Conserve and improve natural ecosystems while protecting human health and well-being.
 * 1) Use life-cycle thinking in all engineering activities.
 * 1) Ensure that all material and energy inputs and outputs are as inherently safe and benign as possible.
 * 1) Minimize depletion of natural resources.
 * 1) Strive to prevent waste.
 * 1) Develop and apply engineering solutions, while being cognizant of local geography, aspirations, and cultures.
 * 1) Create engineering solutions beyond current or dominant technologies; improve, innovate, and invent (technologies) to achieve sustainability.
 * 1) Actively engage communities and stakeholders in development of engineering solutions.

**3. Schematics, PCB Layouts, and Bill of Materials**

B. Bill of Materials
Total Cost of Parts = $1.47
 * Part Name || Part Number || Part Package || Cost || Datasheet URL || Distributor || Comments ||
 * R1 || CFR-25JB-1K0 || Axial || $0.39 || http://www.yageo.com/documents/recent/Leaded-R_CFR_2011.pdf || Digikey 1.0KQBK-ND || Package comes with 5 Resistors ||
 * Q1 || MPSA56RLRMG || TO-92-3 || $0.56 || [] || Digikey [|MPSA56RLRMGOSTB-ND] || Same Transistor will be used for Q3 ||
 * Q2 || MPSA06RLRAG || TO-92-3 || $0.52 || [] || Digikey MPSA06RLRAGOSCT-ND || Same Transistor will be used for Q4 ||

**4. User Manual**

A. How to use the prototype and test suite
__EquipmentSetup__ __GraphingNPN/PNP I-V Characteristic Curves__ __GraphingNPN/PNP Beta vs. Ic Curve__ __SavingData and Opening it on a Spreadsheet__
 * 1) Setup the equipment in the Equipment Setup tab
 * 2) Turnon the Agilent 34401A Digit Multimeter, Keithley2400 Source Meter, and AgilentE3640A DC Power Supply
 * 3) Selectaddress 5 for HP/Agilent E3640A DC Power Supply, address 24 for Keithley 2400Source Meter, and address 22 for HP/Agilent 33401A Digit Multimeter
 * 4) Specifysample count on HP/Agilent 33401A Digit Multimeter for noise reduction.
 * 1) Underthe NPN/PNP I-V Characterization tab, select the transistor type formeasurement
 * 2) Constructthe test circuit for the transistor, as shown on the front panel
 * 3) Specifycollector-emitter voltage (Vce) step size. It has an upper limit of 1V. For PNPtransistor, enter the absolute value of Vce
 * 4) Specifythe number of data points by turning the knob
 * 5) Enterthe number of curve. It has an upper limit of 10 curves
 * 6) Enterbase current step size. It has an upper limit of 10uA
 * 7) Clickthe arrow button in the toolbar to run the program, then click the green STARTbutton on the front panel to graph I-V characteristic curves
 * 1) Underthe NPN/PNP Beta vs. Ic Characterization tab, select the transistor type formeasurement
 * 2) Constructthe test circuit for the transistor, as shown on the front panel
 * 3) Specifycollector-emitter voltage (Vce). It has an upper limit of 10V. For PNPtransistor, enter the absolute value of Vce
 * 4) Specifythe number of data points by turning the knob
 * 5) Clickthe arrow button in the toolbar to run the program, then click the green STARTbutton on the front panel to graph beta vs. Ic curve
 * 1) Create an.xml file on the computer
 * 2) Find thefile’s location in the directory on the front panel
 * 3) Click Saveto save data when it finishes graphing
 * 4) Open the.xml file on Microsoft Excel as a XML table

B. Explain how your prototype and test suite work.
The BJT Curve Tracer 9000 Controls the electrical equipment to control and measure the test circuits for the npn and pnp transistor. This test system is designed for four specific circuit configurations, the npn and pnp Ib-Vce characteristic circuit schematics and the npn and pnp beta-Ic characteristic circuits schematics. The I-V characteristic test and the beta-I characteristic test are placed into two stacked sequences, each initialized by a start button. For each of those tests a select option to determine which type of transistor to test, and according to that selection another stacked sequence executes accordingly. Each of these stacked sequences contains the commands in ordered frames that run the appropriate test according to predefined and user defined variables. The tests are run by communicating with the instruments via the GPIB bus in a safe manner, which only allows one instrument to access the bus at a time. Error lines connected throughout each test system to alert the user of any test problems. The predefined variables are set so that they do not exceed specific voltages, because doing so may potentially fry a transistor by exceeding its power rating. We incorporated data acquisition functionality after each test has completed running. This functionality reads to an .xml file for analysis.

C. Troubleshooting Section
**The program does not control the equipment** First, make sure you turn on the equipment. Second, you have to run the program for itto detect the connected equipment. If the program is not running, click thewhite arrow button in the toolbar to run it. The white arrow will become ablack arrow when the program is running. If the problem persists, it is verylikely that you have selected the wrong GPIB addresses for the equipment.Select address 5 for HP/Agilent E3640A DC Power Supply, address 24 for Keithley2400 Source Meter, and address 22 for Agilent 3340A Digit Multimeter.

**I do not see the GPIB address for the equipment** If you turn on the equipment and the program is running, but you do not see the GPIB addresses, select Refresh in the GPIB address drop-down menu. The program will detect the connected equipment and refresh the GPIB address selection. If the problem persists, turn off the equipment and turn it back on after ten seconds, and refresh the GPIB address selection in the drop-down menu. **The program does not graph I-V characteristic or beta vs. Ic curves** If the programming is running, click the START button to graph. If the problem persists, check the connections of the test circuit and make sure the equipmentare appropriately connected. **The equipment shows an error while graphing characteristic curves** First,make sure you construct the appropriate test circuit for the transistor type you are testing and select the correct transistor type on the front panel. The test circuits for I-V characteristic curves are shown on the front panel under the NPN/PNP I-V Characterization tab. Second, Vce step size and the number of datapoints determine the range of collector-emitter voltage the program sweeps.That being said, if you enter a Vce step size of 1V and select 50 data points,the program will sweep collector-emitter voltage up to 50V! Decrease the number of data points or Vce step size might solve the problem. **It does not save data** It is very likely that the program is not running when you save data. Running the program is not the same as graphing curves or making measurement in BJT CurveTracer 9000. The equipment will not make any measurement until you click the green START button on the front panel. To run the program, click the white arrow button in the toolbar.

=Acknowledgments and References=

Professor Acknowledgements
An assistant professor at Cal Poly, Tina Smilkstein helped us narrow our design approach. Tina was the main customer for our design idea.
 * Tina Smilkstein**

An assistant professor at Cal Poly, Vladimir Podanov helped us verify the proper test circuits to use for bjt characterization.
 * Vladimir Prodanov**