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How to Connect a 2-Wire Thermistor

Temperature is an important variable in scientific experiments. The traditional tool to measure temperature is the thermometer, which has liquid mercury contained within a glass tube. As temperature changes, the volume of the mercury changes, and this can be calibrated to determine a temperature scale. An electronic way of measuring temperature is with components known as thermistors. These are semiconducting devices whose electrical resistance changes with temperature. Thermistors come in two-wire, three wire, and four-wire varieties. The connection to a voltmeter and power source depends upon the thermistor type.

Things You'll Need

Source Meter
Red source meter lead with alligator clip
Black source meter lead with alligator clip

Instructions

- 1
  Connect the voltage leads to the source meter. A source meter is a device that supplies voltage while measuring different quantities such as resistance. Connect the plug side of the red lead to the positive terminal of the source meter. Connect the alligator clip side to the positive terminal of the thermistor.
- 2
  Connect the plug side of the black lead to the negative terminal of the source meter. Connect the alligator clip side to the negative terminal of the thermistor.
- 3
  Switch on the source meter. Press the resistance button to check the thermistor resistance. The thermistor resistance should be around hundreds of kilo-ohms. If so, the thermistor is ready for operation. As the temperature changes, the resistance on the source meter will change.

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