The HOP tool kit has a small digital multimeter,
which can be used for all the electrical measurements you will need to make.
Thermometer:
A small bulb thermometer is included in the
HOP Heat & Temperature kit.
Electronic Temperature Sensors:
Electronic sensors convert
temperature into something you can measure with a meter. As the temperature
changes, you get a change of voltage, current, or resistance, depending
on the sensor. In this lab, you get a chance to explore these different
possiblities.
Figure M1
Temperature Sensors
Thermistor:
This is a semiconductor that conducts electricity much better as it warms
up. As a result, you find that its resistance changes very quickly with
temperature.
Diode:
A diode lets current through in only one direction. When current is going
through it, there is a small voltage drop that depends on temperature.
Thermocouple:
Every junction between two different metals generates a voltage that depends
on temperature. This voltage is not large, but it keeps changing until the
wire melts.
Wire:
Every wire has some resistance and it resistance will change with temperature.
Again, the change is not large, but keeps going until the wire melts.
AD590:
This is a complex electronic circuit that has been constructed to pass a
current equal to its temperature. A bit pricey but accurate and convenient.
