Thermocouple

Is anyone able to tel what the voltage changes are for a thermocouple for
each degree C.

Regards SP
South Africa

On Thu, 24 Jun 2004 11:03:51 +0200, "SP Zeilinga"
wrote:

Is anyone able to tel what the voltage changes are for a thermocouple for
each degree C.

Regards SP
South Africa



First of all, it depends on the type of thermocouple.
K-type is the most common for pottery (R and S platinum types
are too expensive, and J type doesn't go hot enough).
Also, the response is non-linear, so if accuracy is needed
you should use a table. You can download tables of
mV versus temperature for any thermocouple type
from the US National Bureau of Standards. but I don't
have the link... try Googling for "NBS Thermocouple table"
or something.

Anyway, to give you an idea of the values, the output of
a K type at 1200C is 48.828 mV, while at 1210C it is 49.192
mV. These assume the reference junction is at 0C.

Hope this helps.


Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com

SP,
Depends on the "type " of thermocouple (TC) The higher types are type K and
J. There is also a factor known as cold junction compensation. Without the
compensation, if you just hook a volt meter up, you could be off as far as
90 degrees (F) or so. Here's are some sites for a little theory:
http://www.sensoray.com/html/tcapp.htm
http://www.capgo.com/Resources/Senso...pensation.html
http://www.engineeringtoolbox.com/50_559qframed.html

If that doesn't do it for ya, here's some deep theory:
http://www.me.pdx.edu/~gerry/class/M...ermocouple.pdf

Here's where you can view some voltage tables for various types of TC:
http://www.omega.com/temperature/Z/zsection.asp
scroll down to "Thermocouple Reference Data" and select the type and degrees
C or F

also he
http://srdata.nist.gov/its90/menu/menu.html


Good luck!
Tony


http://tonyolsen.com/up/


"SP Zeilinga" wrote in message
...
Is anyone able to tel what the voltage changes are for a thermocouple for
each degree C.

Regards SP
South Africa