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Unformatted text preview: Grade = 92/100 OK. Good data. Some analysis a bit shaky or lacking. For example, I S is proportional to 1 / e (1/kT) . This isnt true, nor is observed in your data. General comment to all the students in my lab sections - Good job in navigating some of the problems with this lab assignment. Clearly, not enough data points were requested in order to get good curve fits and estimates of Ix and n (ideolity factor, which should have been named), or in order to get good values of the slope in the temperature study. Also, the breakdown voltage plot, as some of you figured out, never reached the prescribed value of 1 (did they mean +1e-3?) Hopefully in the future the labs will be available to you prior to your lab day, so you can prepare. AD Albert Ho ECE 315 Tuesday lab Lab 01 writeup Objective: The purpose of this lab was to learn the process of remote operation of the Keithley Source Measurement Units (SMU). Also, we were to examine, using PN- Junction diodes and NPN transistors on a CA3046IC, the IV curves of differential circuit elements. Equipment: PC Keithley CTrace software 2 Keithley SMUs (Source Measurement Units) CA3046IC chip (includes 5 matched NPN-type BJT transistors) 1000 resistor Breadboard + associated wires Experimental Results: Setup We began by setting up SMU1 with a GPIB address of 5 and also setting a timeout of 60 seconds. The timeout became especially important near the end when the SMU sampling delay became unbearably long; oftentimes the timeout presence indicated that there was something wrong happening. Measuring the IV Curve of a Resistor The first experiment we carried out was measuring the IV curve of a resistor. Our objective was to obtain a plot of the current through the resistor vs. the voltage across the resistor. We first inserted a 1000 resistor into our breadboard and connected the ends to the SMU1 device. Using the CTrace software on a PC connected to the SMU1, we set it to sweep the voltage from 0 to 5 volts, with a step size of 0.2 volts resulting in a total of 25 + 1 = 26 measurements. We then selected Linear sweep and Sweep voltage to ensure that the compliance setting allowed sufficient current for our test. The next step was to setup the control of the data acquisition cycle under NPLC. We set a value of 1 for this because the variance of noise for this part of the lab was negligible at a sampling rate of 1 power line cycle of 60 Hz. We then set a delay of 0.02 seconds. After running the sweep cycle, we obtained the following data for the SMU1s measured current through and voltage across the 1000 resistor: Current and Voltage data for sw eeping 1000 resistor: SMU1 Voltage (V) SMU1 Current (A)-9.15E-05 2.25E-07 0.2000563 0.000201 0.4002456 0.000402 0.6003947 0.000603 0.8005232 0.000804 1.000681 0.001005 1.200677 0.001205 1.400668 0.001406 The following figure shows a plot of current through and voltage across the 1000 resistor: Figure A:...
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- Spring '07