Thermocouples

Type K (Chromel / Alumel)
Type K is the ‘general purpose’ thermocouple. It is low cost and, owing to its popularity, it is available in a wide variety of probes. Thermocouples are available in the -200 °C to +1200 °C range. Sensitivity is approx 41 µV/°C. Use type K unless you have a good reason not to.

Type E (Chromel / Constantan)
Type E has a high output (68 µV/°C) which makes it well suited to low temperature (cryogenic) use. Another property is that it is non–magnetic.

Type J (Iron / Constantan)
Limited range (-40 to +750 °C) makes type J less popular than type K. The main application is with old equipment that can not accept ‘modern’ thermocouples. J types should not be used above 760 °C as an abrupt magnetic transformation will cause permanent decalibration.

Type N (Nicrosil / Nisil)
High stability and resistance to high temperature oxidation makes type N suitable for high temperature measurements without the cost of platinum (B,R,S) types. Designed to be an ‘improved’ type K, it is becoming more popular.

Thermocouple types B, R and S are all 'noble' metal thermocouples and exhibit similar characteristics. They are the most stable of all thermocouples, but due to their low sensitivity (approx 10 µV/°C) they are usually only used for high temperature measurement (>300 °C).

Type B (Platinum / Rhodium)
Suited for high temperature measurements up to 1800 °C. Unusually type B thermocouples (due to the shape of their temperature / voltage curve) give the same output at 0 °C and 42 °C. This makes them useless below 50 °C.

Type R (Platinum / Rhodium)
Suited for high temperature measurements up to 1600 °C. Low sensitivity (10 µV/°C) and high cost makes them unsuitable for general purpose use.

Type S (Platinum / Rhodium)
Suited for high temperature measurements up to 1600 °C. Low sensitivity (10 µV/°C) and high cost makes them unsuitable for general purpose use. Due to its high stability type S is used as the standard of calibration for the melting point of gold (1064.43°C).




HOW DOES THIS HELP ME !!!!!

BECAUSE THE HOTTER AN APPLIANCE NEEDS TO GET( ALL THE WAY FROM HOME FURNACES TO INDUSTRIAL FURNACES AT THE STEEL MILLS!!!!!) THE MORE VALUABLE A THERMOCOUPLE YOU HAVE !!! WOO-HOO!


DON'T FORGET KIDDOS, THERMOCOUPLES ARE STARTING TO BE USED IN ELECTRONICS!!!!!


http://www.picotech.com/applications/thermocouple.html