1Experiment 3 - The Curve TracerW. Oldham, W.T. Yeung, R. Lu, and R.T. HoweUC Berkeley EE 105, Spring 20051.0 ObjectivesThe purposes are twofold: (1) Familiarity and competency in use of the HP (now Agi-lent Technologies) 4155A or 4155B as curve tracers, and (2) thorough understanding ofI-V curves for linear and non-linear electronic devices.2.0 PrelabRead the HP 4155A/B instrument manual pages 4-10 -- 4-39 and 3-70 -- 3-77 appended to the end of this experiment and answer these questions.Q1. Review the primer on basic circuit analysis (see Appendix in lab manual). Carefully sketch the I-V characteristics of the following circuits. Use 10 mA full scale with 1mA ticks for the ordinate and 10 V full scale with 1 V ticks for the abscissa.2 K4 K.67 KI(a)V(b)I1.5 V 1 K+−V+−Prelab2 Experiment 3 - The Curve TracerQ2.Sketch the parametric I-V graph of the following circuits (10 mA, 10 V full scale) with the control electrode “G” set at 0, 1, 2, 3, 4, 5 V. We want (y axis) plotted versus (x axis) with as a parameter. See the Supplementary Notes to this lab for help on the relay control. Q3. The canned FET program controls the SMU’s in the following way. Sketch the connections you would use to accomplish the measurement described in Q2a. (Which SMU would you use for which terminal, S, G, or D, and indicate which SMU current and voltage are to be plotted for the vs curve?)IDVDSVGS(a)(b)1 K+−V1 KG1 K1 K10 KIDSDGIDDRelay switchRelay controlSNeed 100 mA complianceon IGVDS-IDIDVDS+_V2I2SMU2+_V1I1SMU1+_V3I3SMU3V1 vs timeV10=0tV2 vs timeV20tV3 vs timeV30tProcedureExperiment 3 - The Curve Tracer 3Note: 3.0 Procedure3.1 HP 4155A/B Setup and Use1. Using the front panel, create a program to generate 2-terminal I-V characteristics with 10 mA, 10 V full scale. Start with the “canned” diode program.2. Generate the I-V curve for the prelab circuits 1a and 1b. Print the graphs.3. Input a program for the 3-terminal parametric I-V measurement described in prelab Question 2a and 2b.4. Generate the I-V curve for the prelab circuits 2a and 2b. Print the graph. (You can start with the “canned” program.)5. Save your program on your floppy.3.2 Diode I-V Characteristics1. Take the 4-quadrant I-V characteristics of a simple silicon diode using the same scale as in 3.1-1. Print the curves. Use a pencil to draw a straight line approximation (2 straight lines to approximate the entire 4-quadrant graph.)2. Take the log I vs linear V characteristics of the diode in the forward-biased quadrant (i.e., for V polarity which causes current flow). Cover the range to . Print the plot. (hint: you can make a simple modification to your program to do this.)4.0 Appendix: General Overview of HP 4155A/B1 IntroductionThese instruments are general-purpose “parameter analyzers,” that is, instruments that can extract, plot, and analyze the terminal characteristics of devices and circuits. In this course we will introduce them (and largely use them) as simple “curve tracers,” that is, tools to display the I vs V behavior of devices and simple circuits containing devices. If you are not completely familiar with the concept of characterizing a box by its terminal I-V characteristics, please review the first appendix to the lab manual. +_Vis the symbol for an ammeter, andis the symbol for a voltage sourceFSET IDS vs VDSI109∠A=101∠ AAppendix: General Overview of HP 4155A/B4 Experiment 3 - The Curve Tracer2 Principle of OperationThe HP 4155A/B instruments are far more powerful than we need, just as your com-puter spreadsheet program is much more powerful than 99% of user requirements). For example, on these instruments there are 4 independent drive/sense nodes called “SMUs” (connection points where the instrument will be happy to apply any potential you desire and monitor the current or, alternatively, apply a current and monitor the potential); 2 voltage source nodes “VSUs;” voltage monitor nodes “VMUs;” as well as some other programmable nodes we don't need to talk about. We will generally use only the three SMUs in this lab.4 Built-in or “Canned” ProgramsYou will find some especially useful built-programs that do almost 100% of the work for you and eliminate the need to take a 3 unit course on the instrument before using it! There is a two-terminal I-V plotter program and two three-terminal programs equally useful. The FET program plots I vs V at one terminal while stepping the voltage at the third. Similarly the BJT program plots I vs V at one terminal while stepping the current at a third.5 Detailed Information on Operating the 41555.1 What compliance meansWhat is the instrument to do if you provide a very low resistance circuit and ask it to ramp a voltage, say, up to 10 V? Self-destructing is not an option, needless to say! You will probably not be happy if your device starts smoking, either.To deal with this question, the user gets to set something called compliance, which is a specification of a maximum parameter value. In part 3.1-1 above, suppose you intended only to look at currents in the 0 - 10 mA range. You would set the compliance of SMU2 to 10mA, and the voltage sweep would stop when that current is reached. A major purpose of the compliance setting is to limit power dissipation in your device under test. The average small device cannot dissipate more than 50-100 mW without risking burn-out. So, if you are sweeping voltage, say over a range of 0-10 V, you might want to limit current to 5 mA, and so forth.5.2 How relay switches operateA generic schematic for a relay switch is provided in the following figure. The device has four electrical terminals: two are connected across the switch and two are con-nected to the electromagnet, which controls the position of the electrical switch. When the applied voltage across the electromagnet exceeds a threshold value, which assume to be 2.5 V for this example), the electrical switch closes and pins 8 and 4 are shorted. If the electromagnet voltage vG drops below the threshold, the switch opens pins 6 and 4 are shorted. The switch operation is illustrated by the plot of switch position versus elec-tromagnet voltage.Appendix: General Overview of HP 4155A/BExperiment 3 - The Curve Tracer 5The schematic on the bottom of the relay identifies the pin numbers. There is a second switch between pins 9, 11, and 13 that is operated by the electromagnet. Failure of the switch to operate could be due to forgetting to
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