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Unformatted text preview: EECS 314 Winter 2009 Homework set 2 Student’s name ___________________________ Discussion section # _______ (Last, First, write legibly, use ink) (use ink) Instructor is not responsible for grading and entering scores for HW papers lacking clear information in the required fields above HW problem for extra credit Wheatstone bridge circuit for temperature control, with PTC and NTC sensors © 2009 Alexander Ganago page 1 of 2 January 18, 2009 This problem contains 3 parts, independent of each other. You can do any part(s) you wish and skip the other(s). The solution is due January 27, 2009. Consider the following circuits for temperature control, each of which includes a Wheatstone bridge, a comparator, and a MOSFET: Two types of sensors can be used as R T : a thermistor with Negative Temperature Coefficient (NTC) and a TemperatureDependent Resistor (TDR) with Positive Temperature Coefficient (PTC). Part 1 2 3 Total EECS 314 Winter 2009 Homework set 2 Student’s name ___________________________ Discussion section # _______ (Last, First, write legibly, use ink) (use ink) Instructor is not responsible for grading and entering scores for HW papers lacking clear information in the required fields above HW problem for extra credit Wheatstone bridge circuit for temperature control, with PTC and NTC sensors © 2009 Alexander Ganago page 2 of 2 January 18, 2009 Part 1 (20 points) For each of type of sensor, explain which circuits (diagrams 1 – 4) can be used if the actuator is a heater, which has to be automatically turned on if temperature gets too low. Write your answers in the table: The circuit can turn on the heater Circuit diagram # Thermistor circuit TDR circuit Comment, if needed 1 Yes / No Yes / No 2 Yes / No Yes / No 3 Yes / No Yes / No 4 Yes / No Yes / No Part 2 (20 points) Consider circuit diagram 3 where R T is a thermistor with 1000 Ω resistance at 25 ºC (see page 40 of US Sensor catalog, attached), R A = 1500 Ω , and R SET = 2000 Ω . Calculate the resistance R 2 to ensure that the actuator is turned on/off at 10 ºC. Your answer: R 2 = ____________________ Ω Part 3 (20 points) Consider circuit diagram 4 where R T is a TDR with 1000 Ω resistance at 0 ºC (see page 4 of Vishay Beyschlag catalog, attached), R A = 2500 Ω , and R SET = 3000 Ω . Calculate the resistance R 2 to ensure that the actuator is turned on/off at 50 ºC....
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This note was uploaded on 10/28/2009 for the course EECS 314 taught by Professor Ganago during the Winter '07 term at University of Michigan.
 Winter '07
 Ganago

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