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HP compatible 5kohm thermistor temperature probe - home made
enut11:
I have a number of 5Kohm bead thermistors and I want to measure temperature with a HP DMM.
Does anyone have access to a temp vs resistance table for the HP thermistor temperature standard?
My specific requirement is to accurately monitor the 40C temperature in a voltage reference oven so if I knew the thermistor resistance that the HP DMM expects at that temp I may be able to select some from my batch of 5K units.
enut11
enut11:
Most of my 5Kohm thermistors measure around 5100-5200 ohms at 25C, ie too high for an accurate temperature indication on a HP DMM.
For the Ref oven, I will be using them over a very narrow temperature range of about 39-41C.
If I shunt the thermistor with a high value resistor to indicate the correct temperature at 40C, this may work. I have a Hanna Checktemp 1 thermometer to help.
Any other ideas?
helius:
The HP E2308A thermistor probe is still available, and not even that expensive.
The datasheet specifies "5000 ohm at 25°C, with a 25°C/125°C ratio of 29.26" which should let you calculate a response curve.
Vgkid:
The thermistor hp used was a 5kohm@25c with a beta of 3891. They were sold by YSI initially, Now sold by Omega.
If you want to go with a very close Beta Value of 3892, then your options greatly increase. With Thermistors sold by ametherm, littlefuse, measurement specialties/Betatherm/TE Connecivity.
YSI
https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.farnell.com/datasheets/169207.pdf&ved=2ahUKEwjKgIeb8froAhWbl3IEHTISD40QFjAAegQICBAB&usg=AOvVaw2mRj7qTnQ4YiPiIiguA8f9
enut11:
--- Quote from: helius on April 22, 2020, 12:48:48 am ---The HP E2308A thermistor probe is still available, and not even that expensive.
The datasheet specifies "5000 ohm at 25°C, with a 25°C/125°C ratio of 29.26" which should let you calculate a response curve.
--- End quote ---
Thanks. In this application I will have to build my own probe due to space restriction in the oven. I will look for a suitable bead thermistor.
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