Thanks for all answers
First question to answer is, at what temperatures you want to operate the temperature sensor.
-branadic-
I use those sensor mostly under T=200C - T&M ovens. The temperature in most application even does not go beyond 85C.
I have many of then some have Au or Ag but some are Ni - Most of the time I use easy soldered components - unfortunately my internal stock runs emty and I have to switch to dificult to solder parts.
I use spot welding using graphite electrodes pulled out from zinc carbon batteries.
The graphite is used because it does not stick to both welded wires.
Popular spot welders used for LiPo battery packets welding are not sufficient to my experience.
Below some photos from the deep past.
Regarding reliability: approximately 30 sensors work without failures for 6 years operating at 200'C.
Kynar insulation of the wires puts a limit here.
Thanks, I've started building the similar spot welder setup.
So I will try to find use of those nickel wired PT100/1000 sensors.
By my next purchase I will careful select Au/Ag plated wires.
- they are easier to solder
- the thermocouple effect is less dominant compared to Ni -> Cu.
Another aspect is the long term stability of those sensors. I was not aware about it. I find link below interesting
https://www.eevblog.com/forum/metrology/long-term-stability-of-temperature-sensors/Background information - My reference resistor project
----------------------------------------------------------------------------
for my reference resistor project I want to have temperature sensor.
Four Vishay resistors in two serial two parallel are submerged in silone oil bath.
Mechanical part is almost ready.
All ordered component arrived
I tough that temperature sesnor in silicone oil bath was a easy task. But it seems that PT sensors with good defined long term stability are rare.
Happily my requirements are not tight - something like T=0.1K @15..20years. is still ok. Inert silicone oil environment should help too.
I start leaning toward NTC for this application
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwjI-NiY-OD7AhXQsKQKHacnCQsQFnoECAYQAQ&url=https%3A%2F%2Fwww.eevblog.com%2Fforum%2Fmetrology%2Flong-term-stability-of-temperature-sensors%2F%3Faction%3Ddlattach%3Battach%3D412153&usg=AOvVaw09Khd8-kgf81hOig-AK4hGSummary : The SMD-type sensor from Muratamanufacturing (NCP15XH103D03RC) intriguingly showed the least drift performance of 0.492 mK/year pp.
Greetings,
Miro