Online guide for hobby-level DIY thermocouples?

[_]

I think I'd like to experiment measuring temperature with some small
electrical meters - freezing to boiling or a bit higher. Pointers to
useful info on the web sought - thanks...

 

[John Popelish]

I think I'd like to experiment measuring temperature with some small
electrical meters - freezing to boiling or a bit higher. Pointers to
useful info on the web sought - thanks...

Do a Google search for [thermocouple tutorial].

You might also search for [Seebeck effect tutorial], since
this effect is the cause of the voltage produced by a
thermocouple.

You might start with:
http://en.wikipedia.org/wiki/Thermocouple
http://www.fis.unipr.it/pub/materia...National-Instruments-Application-Note-043.pdf

 

[John Popelish]

Here is another pretty good reference:
http://materials.usask.ca/samples/Thermoelectric-Seebeck.pdf

 

[Spehro Pefhany]

I think I'd like to experiment measuring temperature with some small
electrical meters - freezing to boiling or a bit higher. Pointers to
useful info on the web sought - thanks...

That's not a great range in which to be using a thermocouple. Did you
have some specific reason to want to use a T/C?


Best regards,
Spehro Pefhany

 

[_]

That's not a great range in which to be using a thermocouple. Did you
have some specific reason to want to use a T/C?

No - just thought that for an analogue meter a device that made
(milli)volts all by itself would be likely to keep things simple. What's
better?

 

[Spehro Pefhany]

No - just thought that for an analogue meter a device that made
(milli)volts all by itself would be likely to keep things simple. What's
better?

A thermistor or semiconductor sensor would be simpler to work with.
National, for example, has some. Thermistors are nonlinear so a bit
harder to work with, but cheaper and more accurate in quantity (not
necessarily more stable). A coil of copper wire can be a cheap
temperature sensor. A loose coil of thin Pt wire is one of the most
stable temperature sensors made. If you are not so fussy, a thin film
of the stuff will do. HVAC folks use thin films of base metal stuff
like nickel.

Here's a semiconductor sensor that costs around $1 in small
quantities: http://cache.national.com/ds/LM/LM94022.pdf

You need a sensor such as the above in order to be able to use a
thermocouple anyway! (for cold junction compensation).


Best regards,
Spehro Pefhany