1 Massachusetts Institute of Technology Department of Electrical Engineering and Computer Science 6 002 Electronic Circuits Fall 2003 Quiz 1 Please write your name on each page of the exam in the space provided and circle the name of your recitation instructor and the time of your recitation at the bottom of this page Please verify that there are 14 pages in your exam To the extent possible do all of your work on the pages contained within this exam In particular try to do your work for each question within the boundaries of the question or on the back side of the page preceding the question Extra pages are also available at the end of your exam You may use one double sided page of notes and a calculator while taking this exam Good luck Problem Points Score Grader 1 20 2 20 3 15 4 25 5 20 Total 100 Name Instructor Time Perreault 10 11 Antoniadis 11 Chaniotakis 11 12 Umans 12 1 Kolodziejski 2 3 2 Name Problem 1 20 Points 12 2 8 16 4 A 3V 4 4 2 8 4 6A 4 B A Determine the values of R1 R2 and R3 so that the entire circuit above is equivalent to the simpler circuit shown below for the purpose of creating the Norton equivalent of the above circuit when viewed from its port labeled A B R1 R3 3V A R2 6A B R1 R2 R3 over Name 3 B Assuming R1 R2 R3 8 in the circuit in Part A draw the Norton equivalent of the circuit when viewed from its A B port Note that these may not be the values you obtained in Part A Be sure to specify element values units and polarities 4 Name Problem 2 20 Points The zener diode in the circuit below has the v i characteristic shown at the right 7 k iS iD iD vS vD 3 k 4 5 0 0 6 vD volts A For the input voltage vS shown below indicate the time intervals where the diode is ON conducting a current and OFF open circuit Label the boundaries with numerical values on the plot below vS t volts 20 10 20 20 30 40 t ms 5 Name B For the input voltage vS shown in Part A sketch the zener diode voltage waveform vD t Label all breakpoint coordinates with values and units vD t volts 10 20 30 40 t ms 6 Name Problem 3 15 Points A The digital circuit below has logic inputs P1 P2 Pn S1 S2 Sm and output X Assuming that the element values are chosen so that the circuit satisfies a static discipline what is the logic function computed by the circuit VS RL P1 P2 P3 Pn X S1 S2 S3 Sm X B For what choice of logic input values is the maximum power consumed by the circuit Assume that all the MOSFETs have a nonzero value for their ON resistance 7 Name Problem 4 25 Points The semiconductor device team at Yenron Inc has created a remarkable new device called the LOSFET The symbol for the device and its equivalent circuit model are shown below iDS G vGS D vDS S iDS G iDS D D vDS vGS 1mA G S 1k vDS S vGS vGS 2V vGS 2V Like the MOSFET studied in 6 002 the LOSFET has three terminals labeled G gate D drain and S source When vGS 2V the device displays an open circuit between its D and S terminals and when vGS 2V the device behavior between its D and S terminals can be modeled by a 1mA current source in parallel with a 1k resistor The current into the gate G is always 0 A Plot the iDS versus vDS curve for the LOSFET when vGS 2V in the range 5V vDS 5V iDS mA 5 4 3 2 1 0 1 2 3 4 5 vDS volts 8 Name B Plot the iDS versus vDS curve for the LOSFET when vGS 2V in the range 5V vDS 5V Clearly mark all relevant intercept values on the two axes iDS mA 5 4 3 2 1 0 1 2 3 4 5 vDS volts 9 Name C Yenron engineers use the LOSFET to build the inverter circuit shown below VS RL G D vOUT vIN S Assuming that VS 4V and RL 1k determine vOU T for i vIN 0V and ii vIN 4V Remember that the LOSFET turns ON for vGS 2V i vIN 0V vOU T ii vIN 4V vOU T Name 10 D Yenron develops several inverters using the same LOSFET but with various values of VS and RL One of the inverters produces a high output of vOU T 5V and a low output of vOU T 1V Note that although this inverter has the same internal circuit as the inverter described earlier this inverter has different values of RL and VS Determine whether this inverter satisfies a static discipline with the following voltage thresholds VOH 3 5V VOL 0 5V VIH 2 5V and VIL 1 9V Simply answer yes if it satisfies the static discipline If your answer is no indicate a threshold that is not met by the device E Next determine whether the inverter in Part D satisfies a static discipline with the following voltage thresholds VOH 3 0V VOL 1 5V VIH 1 9V and VIL 1 7V Simply answer yes if it satisfies the static discipline If your answer is no indicate a threshold that is not met by the device 11 Name Problem 5 20 Points A Yikes Inc has developed the new device shown below that requires the application of voltages in the range 0V to 3V at its A B port A B The Yikes engineers rummage through their supply room but cannot find an appropriate variable voltage source rather they find only one 9V battery and several 1k fixed and variable resistors A 1k variable resistor can vary between 0 and 1k Symbols for these elements are shown below 9V 9V battery only one available 1k 1k resistor many available 1k 1k variable resistor many available You are called in as a 6 002 expert to help the Yikes engineers The Yikes engineers also tell you that the resistance looking into the A B port of the device is infinite Design a circuit that can supply voltages in the exact range 0V to 3V using only the circuit elements in the supply room Clearly mark the terminals in your circuit which must be connected to the A B port of the device Name 12 B Always looking to help your client you notice that the device would work even better if voltages in the exact range 3V to 3V were applied at its A B port Design a circuit that can supply these voltages using only the elements available in the supply room Hint Try producing two separate voltages v1 and v2 that can be varied independently such that v1 v2 produces the desired output voltage End Name 13 Name 14
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