3/3 Thermal Resistor

In the morning, we were given a pop quiz where we had multiple junctions leaving us with many ugly equations and numerous equations and unknowns. After trying to solve it the conventional way, we use the mesh current method to solve for each of the unknown currents and voltages.

We have a resistor that changes in resistance based on the temperature. We calculated how much of a temperature change would cause the voltage going through this resistor to change by .5V. We found that the temperature change required for this was close to .4704C.

From the graph above, we found the resistance of the thermal resistor to be 11.55 kOhms @ 25C and 7.28 kOhms @ 37C. We also found the difference in voltage between the +Vout and -Vout if the voltage going in is 5V at each 25C and 37C.

We are given a circuit where we have the resistor from the problem before and normal resistor. We calculate the resistance of the resistor at the specific temperature using the graph from before. From this resistance, we calculated the resistance of the other resistor if given the voltage going out when the thermal resistor is at 25C and 37C.

We set up a breadboard circuit where we test the thermal resistor for its actual resistance at room temperature (25C) and at body temperature (37C) if the voltage going through the resistor is 5V.

We plug the thermal resistor into the breadboard and use the multimeter to find the actual resistance of the thermal resistor at body temperature (37C). We found it to be very close to our theoretical value 7.38 kOhms.