EL 3302
PRE-LAB 3: THERMISTOR-BASED CIRCUIT FOR MEASURING TEMPERATURE
GETTING
1. Assume that the source voltage is 9 V and that 𝑅2 = 10 𝑘Ω.
Suppose that 𝑣2 is measured. Its value is measured to be 4 V. Find the following. (Remember to include
the appropriate units of measure.)
a) 𝑣1
b) 𝑅1
c) 𝑖
d) Power supplied by the source
e) Power absorbed by each resistor
2. Consider the same circuit as shown in Problem 1 but with this modification. Now, suppose that 𝑅1 is a
Thermistor which has the following Resistance-Temperature characteristic displayed in the Figure below.
Resistance Vs Temperature
Resistance (kOhms)
25
20
15
10
5
0
0
20
40
60
80
100
120
Temperature (degrees C))
Determine the voltage 𝑣2 that would be produced by the device at the following temperatures:
a) 0
b) 23
c) 36
d) 80
e) 100
EL 3302
PRE-LAB 3: THERMISTOR-BASED CIRCUIT FOR MEASURING TEMPERATURE
GETTING
3. A group of E-Lead graduates form a company after graduation. The company develops an electronic
device that produces a voltage that is sensitive to speed. They wish to market it to automobile makers.
The Table that follows displays measurements of the voltage produced by the device for different values
of speed measured in miles/hour.
Voltage
(Volts)
0.5
2
4
6
9
Speed
(mph)
0
30
50
70
100
a) Determine a mathematical expression that relates speed to voltage.
b) If the device produces a voltage of 5.3 V, what is the corresponding speed?
c) How much voltage would be produced by the device if the speed is 64 mph?