Question

The student investigates how the resistance of a thermistor varies with temperature. The student has a power supply, a thermistor, an ammeter, a voltmeter and some connecting leads. Describe an investigation the student could carry out to measure the resistance of a thermistor between –10 °C and 70 °C.

Your answer should include:

1. Any other apparatus the student will need
2. The measurements to be taken
3. How the data should be processed.

(This question is worth 6 marks on my assignment so I just really want to get down the best possible answer for it.)

Answer 1

The characteristics of the thermistors allow to design an experiment to analyze the dependence of resistance with temperature;

      1) We set up the circuit

      2) We look for the current of the circuit and we keep it fixed.

      3) We look for the thermistor resistances for each temperature.

      4) Plot Resistance versus Temperature.

A Thermitor is an element whose resistance changes with temperature, for example a platinum resistance.

An experiment that we can carry out to measure is to set up the attached circuit where we have:

• A DC power supply.

• A resistor to control the maximum current in the circuit and avoid thermal problems in the thermistor.

• A thermistor.

• A thermometer placed next to the thermistor.

• A source of heat under the thermistor under a glass with ice and water, but without affecting the other elements of the circuit.

Let's start by looking for the current in the circuit.

In thermistors, the resistance for room temperature is given, so if we measure the voltage across the fixed resistor, we can shrink the voltage across the thermistor.

         

           $V_{source} = V_R + V_{therm} \\V_{therm} = V_{source} - V_R \\ i = \frac{V_{therm} }{R_{therm}}$

This current remains fixed, since the fixed resistance is greater than the resistance of the thermistor throughout the range.

Second step.

Now we can change the temperature that is measured in the thermometer, for each temperature the voltage in the fixed resistance is measured, the resistance in the thermistor is calculated.

        $R_{therm} = \frac{V_{source} - V_R}{i}$  

Third step.

We end with a graph of resistance versus temperature of the curve obtained, it is possible to understand the behavior of the resistance of the thermistor with temperature.

In conclusion with the characteristics of thermistors we can design an experiment to analyze the dependence of resistance with temperature:

      1) We set up the circuit

      2) We look for the current of the circuit and we keep it fixed.

      3) We look for the thermistor resistances for each temperature.

      4) Plot Resistance versus Temperature.

Learn more about thermistors here:  brainly.com/question/15690488