Custom thermistor

General Discussion
1

Regarding the custom thermistor. I am setting Klipper and for extruder options, I am using a custom thermistor because none of the common ones work (generic semitec or max ). I don’t have a specific name of my thermistor but I got it from an old printer. Using Marlin with thermistor 147 which is pt100 pull up 4.7k worked fine. Setting the following settings shows 275 C , ADC out of range
[thermistor my_thermistor]
temperature1: 25
resistance1: 103180
temperature2: 150
resistance2: 1366.2
temperature3: 250
resistance3: 168.6

2
  1. A PT100 cannot be connected directly, it needs an amplifier like the MAX3186.
  2. A thermistor that does not work with Generic 3950 is likely not a NTC
  3. Without any information on the type, it will be very hard to support
  4. Please follow How-To Ask for Help for all future requests
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3

You don’t have a custom Thermistor. Looking at your numbers, I can see that it’s an NTC and it’s a 100k NTC Thermistor with a Beta of 4369.

Using measured values like you have, you can calculate your Beta value using a tool like:

As @Sineos said, when asking a question, please provide all the requested information when you put in your post.

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4

This configuration worked for pt100:
sensor_type: PT1000
pullup_resistor : 47000

5

I’m quite sure that this does not work or at least does not give any reliable results. Again, a real PT100 PTC cannot be attached to a regular thermistor port (A PT1000 PTC can be attached this way).
For PT100 an amplifier board is mandatory.

6

ll take your word. It’s unreliable because the room temperature is 20 more or less and the thermistor marks 25C. so error is high but for testing its ok . Ill change in future to a reliable one . What is the thermistor that works pretty fine with Klipper and is also reliable?

7

What you are doing for testing is completely on your side, but please be so kind to refrain from stating that something is working, which apparently is not. Other users here are reading it as well and will be lead to believing this.

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8

Can you describe how you made your measurements at temperature (ie how do you know that the thermistor is at 250C - or even 25C) as well as the equipment that you used?