Liquid Crystal Based

Those based on liquid crystals, and reversibly cover the range of approximately -30°C to 120°C, with a measurement "bandwidth" of 10°C with 1°C accuracy.

Paint Based

Other materials are used to manufacture nonreversible indicators, labels and strips. These are available for temperatures up to 1270°C. Typically these rely on material crystal lattice or phase changes at a particular temperature. They are particularly good in recording if a device has exceeded its designed temperature limit.

Applications

The application of this form of sensor is very diverse. A commonly seen application is for the measurement of aquarium temperature using self adhesive strips such as show to the left. Contrary to what may be expected in a world of electronics, the demand for these types of products is increasing due to their ease of use and very visual output.

See the following manufacturers for more information:

• Tempil, Inc
  A leading manufacturer of chemical temperature indicators especially for the metal fabrication and medical product sterilization industries
• Thermographic Measurement Ltd
  for thermal strips and spots
• Lakfbriek Korthals BV
  Therm-O-Signal coatings and indicating paints
• TIP TEMPerature Products Inc
  A US supplier of a wide range of temperature measuring products including paints and strips
• B+H Colour Change Ltd
  A UK based company specializing in custom color change products that incorporate temperature sensitive inks and plastics
• Hallcrest Inc
  Manufacturers of thermochromic products with an interesting product range from consumer to industrial and medical.