Download PreFinal thermQ

Thermistor Circuit Analysis:
2Ω
10 Ω
10 Ω
10 Ω
5Ω
10 Ω
+
10 V
10 V
Find I, ∆V, R, P for each resistor and Va, Vb and Vc for each circuit.
+
+
10 V
Now recall the is the thermistor circuit used in one of our labs. The thermistor changed
resistance as the temperature changed. The other resistor in the circuit is a fixed 10,000
ohm resistor. Instead of measuring this resistance if the thermistor directly at different
temperatures, you measured the voltage labeled Vout. This voltage was the voltage
difference across the fixed resistor in the lab.
a) There is an approximate rating for the
thermistor in the circuit diagram (10k
connect to (+)
ohms @ 25°C). Solve for the total current terminal o n battery
in the circuit. Solve for the voltage
between the resistors when a 9 V battery is
thermistor
used.
+9V
Battery
10kΩ @ 25°C
(+) on Voltmeter
b) Find the power output for each resistor for
this situation in part a.
10kΩ
Vout
ground:
connect to (-)
terminal o n battery
(-) on Voltmeter
c) Now redraw that circuit and include the battery that you used for the experiment. In
what way are the circuits above similar to the thermistor circuit?
d) Find a voltage reading and associated temperature from your lab report. Label the
voltage on the circuit diagram. Now solve for the current, all voltages and all
resistances in the circuit at that temperature.
e) Find the power output for each resistor at this temperature.
f) Do parts d-e for three different temperatures.