Weewooday 10個 3M Kタイプ 熱電対温度プローブ センサー 温度センシング ライン Kタイプ ミニコネクタ 熱電対線測定範囲 -50～400℃ TM902C/ TES1310対応

When compared to the one that came with my test equipment these measure very close to same temp I was getting from the original one.

Nice 30 Gauge wire type-K thermocouples. Listing does not state wire gauge. Generous length that you can use to make more thermocouples. Fiberglass insulation, good for reasonably high temperatures. Sturdy Flame Welded bead. The bead is about 1 mm diameter and is quick to respond. The wire is folded, not looped like the listing shows, so it needs to be straightened. The black polyolefin heat shrink insulation should be removed if you are going to use this above about 150 C. Just carefully slice it with a razor blade and pull it off. The end of the thermocouple is twisted and bent, so it will need to be straightened before use as I have shown in the upper part of the photo. Make sure the bare wires do not touch except at the bead if you need to precisely locate the measurement point. I didn't pull back the outer jacket to see the color coding; it might be non-standard. If you need to check polarity, Alumel is magnetic below 152 °C and is the (-) side. Minus one star for minor correctable deficiencies.

We have a very old TC welding machine that we used to make Thermo Couples. It works well and is very handy. I purchased these TCs as a test to see if we could use purchased TCs, if our welder failed. The purchased TCs from this vendor are equal in every way to those we make. I compared the temperature reading with a quality Fluke, handheld meter. The TCs we make (that I trust) read identical to those from the vendor. The only question might be the quality of the insulation. I say “question” because I have not tested the resistance to burning of their fiberglass insulation but it appears to be authentic fiberglass sheathing. I will test heat resistance and update this post.

Some works others don’t like

This may be nit-picky, but the photo shows the thermocouples wrapped in a circle. When you get them they are neatly packaged in a folded "hank", as is common with most cords for electronics. Why does it matter? I have used these for years. No matter how careful you are, unfolding and straightening the wires, they want to get a tight kink in them, exactly where they were previously folded for packaging. That shortens their life. Considering the reasonable price, and good temperature resistance, I guess they last long enough. Accuracy is good for the price. Not calibration grade, but good for almost all but the most demanding measurements.