In this activity you will investigate the resistance characteristics of the thermistor and then examine its use in a voltage divider.
Equipment
Thermister
Small balloon
Beaker
Ice
Bunsen burner/ hot water jug
Digital Multi Meter
Thermometer
Connect the thermister to some connecting wires and place it in the balloon. Put some ice blocks in a little water and immerse the thermister in it. Measure the resistance using the DMM and the thermometer. Add a little boiling water and take another measure. Continue adding warm water, after a while you may have to pour off some of the water. Try to take lots of readings and get a reading up to as close as boiling as possible. Enter your data onto a spread sheet.
Tabulate your results on excel and graph a temperature vs resistance.
Comment on the shape of the graph and the relationship between temperature and resistance for the Thermister.
1. Use your characteristic curve and the thermistor to find the temperature of:
(a) the room
(b) water from a hot-water tap
(c) water from a cold-water tap
(d) a cup of coffee.