Adding connector to NTC temp probe

emjay · Jun 27, 2011

I'm using a temp controller much like the one used in the eBay temp controller thread. Except I simply wired it into an extension cord rather than putting it into an enclosure.

The temperature probe has two wires that connect directly to the terminals. I want to clean this up a bit, so I want to put it into an enclosure, but I also don't want any wires to simply run through a hole. Rather, I want to connect the wires to some sort of male connector, and have a receptacle mounted in the enclosure, with wires running from THERE to the terminals.

But, while I've done a fair amount of wiring, and can do it myself no problem, I'm unsure of a few things. For instance, what would be the best connector type to use? I'm thinking maybe using a TRS (headphone) connector, and using the left-right stereo lines for the two wires I need. Or maybe a BNC connector? Basically, I'm not sure if stuff like these will allow it to function properly. Is there another type of connector that is more ideal?

Also, will adding the slightly additional length of wire, as well as the connectors, mess with the accuracy of the temperature readings because of increased impedance or anything? I'm fine with having to recalibrate it, but that's only possible if only the offset is affected. If the slope is also affected significantly, it would make the whole thing rather useless.

Any help would be hugely appreciated.

Catt22 · Jun 28, 2011

emjay said:
I'm using a temp controller much like the one used in the eBay temp controller thread. Except I simply wired it into an extension cord rather than putting it into an enclosure.

The temperature probe has two wires that connect directly to the terminals. I want to clean this up a bit, so I want to put it into an enclosure, but I also don't want any wires to simply run through a hole. Rather, I want to connect the wires to some sort of male connector, and have a receptacle mounted in the enclosure, with wires running from THERE to the terminals.

But, while I've done a fair amount of wiring, and can do it myself no problem, I'm unsure of a few things. For instance, what would be the best connector type to use? I'm thinking maybe using a TRS (headphone) connector, and using the left-right stereo lines for the two wires I need. Or maybe a BNC connector? Basically, I'm not sure if stuff like these will allow it to function properly. Is there another type of connector that is more ideal?

Also, will adding the slightly additional length of wire, as well as the connectors, mess with the accuracy of the temperature readings because of increased impedance or anything? I'm fine with having to recalibrate it, but that's only possible if only the offset is affected. If the slope is also affected significantly, it would make the whole thing rather useless.

Any help would be hugely appreciated.

You can extend the probe wires without significantly affecting the accuracy or the calibration. There are limits, of course, but it's on the order of hundreds of feet with the proper gauge wire. Your short run will be no problem at all.

I use a standard 1/4" mono headphone type connector. You could use the stereo version, but the mono was available and just what I needed. Works great and does not interfere with the readings or calibration. It's convenient to be able to plug and play, then stow when not in use.

emjay · Jun 28, 2011

Catt22 said:
You can extend the probe wires without significantly affecting the accuracy or the calibration. There are limits, of course, but it's on the order of hundreds of feet with the proper gauge wire. Your short run will be no problem at all.

I use a standard 1/4" mono headphone type connector. You could use the stereo version, but the mono was available and just what I needed. Works great and does not interfere with the readings or calibration. It's convenient to be able to plug and play, then stow when not in use.

How do you use the mono with two wires?

Catt22 · Jun 28, 2011

emjay said:
How do you use the mono with two wires?

There are two terminals on the mono jack. Stereo versions have four. The probe has two wires and its not polarity specific.

emjay · Jun 28, 2011

Catt22 said:
There are two terminals on the mono jack. Stereo versions have four. The probe has two wires and its not polarity specific.

Oh, fantastic. Thanks a lot. It will be nice to be able to easily disconnect all the wires from the box.

audger · Jun 28, 2011

you can pretty much use any connector you have ever seen. a favorite seems to be XLR microphone ends. i like the 1/4" headphone jack though, never though of that one, and would probably be much cheaper.