ion_four

Does anyone know where I can get a cheap thermocouple with like 6-8ft of wire? I don't want to buy it through autometer, when apparently you can get the right type "K-type thermocouple" for like $30-40, but I can't find any this cheap, except in australia, heh.

ion_four

no one knows where I can buy one for cheap? The only place I've been able to find them is from other autoracing sites and they sell them for about $80, too much.

ttt

BigMoose

Go to http://www.omega.com/ppt/pptsc.asp?ref=JQIN&Nav=tema04
the type K probe alone is $26 bucks I think it comes with the connectors. Use the wire extension wire from your old one. You have to use Type K connectors and Type K extension wire up to the cold junction compensation reference junction for optimum accuracy.

The root url is http://www.omega.com This is where I buy all my thermocouple stuff from. They also have great technical reference documents on the site.

Regards,
BigMoose

falcongsr

cool! what guages do these mate to?

BigMoose

Their catalog has a bunch of readouts/gauges. Most are either stand alone hand helds or bench top "laboratory quality" units. Take a browse thru their web catalog it is at good one.

However a type K thermocouple is a type K thermocouple though. So the pieces parts are generic in function.

For my applications I design and build my own cold junction compenstation, amplification, signal processing, and display and interface units. So I tend not to browse the commercial stuff except for pieces parts.

Regards,
BigMoose

falcongsr

well then, bigmoose, you're my new best friend

dbman96

Don't they have them any shorter than 12" sheaths?? That's a little ungainly for sticking into your #3 exhaust runner

ion_four

okay, I'm really dense...the thing is that I don't have an old probe to use the wire from, so I need one...I've looked all over the omega site (above) but I'm not sure what I need, can someone help me? I found the probe, but I'm not sure what I need as far as connecting wire (about 6-8feet, to be safe) and some kind of terminal to plug it into that I can solder to a board...
I'd really appreciate anything!!

ion_four

Does anyone know what this special wire and or terminal is called? Is it just type k?

BigMoose

I have been carrying on a nice conversation with ion-four on IM. He plans on using a 10 bar graph display for his EGT and an Analog Devices AD595 for the amplification and ice point reference. Here were my latest comments to him as they may be useful to others:

I took a look at the application note at <A HREF="http://www.analog.com/library/applicationNotes/dataConverters/PDF/AN369.pdf
" TARGET="_blank">http://www.analog.com/library/applic.../PDF/AN369.pdf
</a> and although the chip is rated to 50 deg C for best accuracy, they show the degradation in accuracy up to a chip temperature of 125 deg C as less than 10 deg C. Considering that you are using a bar graph output, here is what I would consider doing.

Move the IC from the passenger compartment to the end of the thermocouple in the engine compartment. Make your little board as small as possible and bring the sheathed thermocouple leads right into pins 1 and 14 on the AD 595. Or use one of the Yellow Chromel Alumel (Type K connectors) there. This thing should package very nicely. I use devcon epoxy paste to pot my one off type experiments.

That way you save on connectors, and Type K extension wire.

Here are the connectors I use: http://www.omega.com/ppt/pptsc.asp?ref=NMP&Nav=temg03

Here is the wiire I use: http://www.omega.com/ppt/pptsc.asp?ref=XC_K_TC_WIRE&Nav=temh06

Probes are here (6 inchers): http://www.omega.com/ppt/pptsc.asp?ref=JMQSS&Nav=tema04

Good Luck,
Regards,
BigMoose