Looking for a compatible temperature display

kinglerch

I have a thermistor with a standard 10K ohm at 25 deg C (77 deg F) and resistance curve as shown below. It seems like this is a fairly standard thermistor. Where could I find a digital temperature display that would compatible with this thermistor?

<em>T (F) Rx (Ohms)

50 19900

55 17400

60 15300

65 13500

70 11900

75 10500

80 9300

85 8300

90 7300

95 6500

100 5800

105 5200

110 4700

115 4200

120 3800

...</em>

Jean-David Beyer

If you are a do-it-yourselfer, ...

.... you could probably hook it up to your computer and put in any curve you like. You would need some kind of interface board, but Google might find you one.

kinglerch

looking for something a bit simpler

Apparently the resistance curve for my thermistor is relatively common, maybe the most common. But finding detailed information on a thermistor or compatible temperature display seems very difficult. Sometimes only manufacturers have this information.



The closest I've found are home heating controls, but they are even more complicated than what I need. Who sells just temperature meters that are compatible with certain types of thermistors?

cattledog

Tekmar 10K slab sensor

This data looks similar to the resistance/temperature for the Tekmar slab sensors 072,073,079.  Tekmar has a data brochure D 079 documenting these slab sensors. Downlod it fromt he website.  I have used this sensor with the 510-512 programmable thermostats as well as the 150 setpoint controller.  It's probably compatible with other Tekmar controllers.

awaltiii

Thermistor Information

I wanted to provide some additional information on thermistors for you.

There are a number of 10K thermistors that appear to be the same where in fact there are 2 or 3 different curves relating to resistance vs temperature.  Since almost all thermistors are referenced to 25° C (77° F) the differences may appear unnoticeable at temperatures near 77° F.

I had made a monitoring system for my house many years ago and finally decided to use thermistors as the temperature sensor of choice.  They are fairly cheap and needed a minimum of support circuitry for monitoring.  I ended up using the power from the computer to supply the correct voltage and wrote a program to linearize the thermistor output. 

My original intent was to monitor my house and have the computer (a VIC-20 from the early 80's) monitor the temperatures and control the heating system in my house.  I encountered locking up problems with the VIC and could not solve that problem.  So, I used the VIC to monitor temperatures for a few years and left the project at that point.

If you need a display, you can probably find a display including a thermistor on Ebay for less than $20.  But, the displays usually come with their own thermistor.  Most likely due to the multiple curves in which the thermistors come in.

To get some information on thermistors, you can go to "Quality Thermistor" website.  They have white papers on thermistor projects in which you could make a circuit which you want to do using an inexpensive digital meter from Ebay instead of a DVM.  But, you will need to have some electronics background.

Other thermistor manufacturers may have "white papers" with details on how to make a display.  Just do an Internet search on thermistor and you will find plenty of information.

Another option is to use a thermocouple with meter.  Again, I saw one on Ebay that sold for around $25.

Empire_2

Try Dwyer Company

They have a full line is temperature measuring devices and they should be able to help you out.



Mike T.

awaltiii

Dwyer Temperature Indicator

A few years ago Dwyer bought Love Controls who currently make a panel mont digital temperature indicator for around $35 with a maximum reading of 99°C.  The display uses a 1000 ohm NTC thermistor for a sensor which is reasonably priced around $6.

There are two indicators available... one without an adjustment pot (to get a more accurate reading) for less the $35 and a model with a calibration pot for a little over $35.

Love Controls are quality products (I have used them) and I wasn't aware they now have a low cost line of temperature indicators with thermistor inputs.

The only disadvantage is you can't use the 10K thermistor you currently have on this display.  My guess is though that other manufcturers may have a similar display that utilizes a 10K thermistor.