Hallo guys. I bought a second hand TOPTRONIC T48 multimeter. When i measure temperature with temperature lead (supplied)  and  positive and negative propes correctly plugged in and dial set to C. when switched on reading is +19 degree Celsuis. If i put sensor in say oven or on element the  reading start dropping even into the negative. Is this correct on this meter? I  personally do not think so.   

3 hours ago, EnerTek said:

Is this correct on this meter? I

No definetly not. It seems you got the incorrect probe( thermistor) with the multimeter. You get 2 types of thermistors NTC and PTC. NTC is most commonly used. For an NTC thermistor, as temperature increases, resistance decreases. For a PTC thermistor as temperature increases, resistance increases.

This is the probe normally used with a wide variety of multimeters

Thermocouple Type-K Temperature Probe On Wire Lead. -40~250Deg Suitable For Ut30C 

https://www.livestainable.co.za/product/temperature-probe-bead-40-250d-k-type-ut-t10k/?gad_source=1&gclid=CjwKCAjwx4O4BhAnEiwA42SbVINsK4TSxNrYnNVJJXRWXearsG8iPYcfyzQSlfZ45dQArF2QRQSTgRoCqNoQAvD_BwE

Edited October 5, 2024Oct 5 by TaliaB

4 hours ago, EnerTek said:

Hallo guys. I bought a second hand TOPTRONIC T48 multimeter. When i measure temperature with temperature lead (supplied)  and  positive and negative propes correctly plugged in and dial set to C. when switched on reading is +19 degree Celsuis. If i put sensor in say oven or on element the  reading start dropping even into the negative. Is this correct on this meter? I  personally do not think so.   

As the standard probe is only to 250 deg it could have overheated when measuring the high temp of an element?

When it measures 19 hold the tip between your fingers and see if it goes up.

Edited October 5, 2024Oct 5 by Scorp007

15 hours ago, TaliaB said:

You get 2 types of thermistors NTC and PTC.

And the picture you attached (which is also what is usually used with multimeters) is a thermocouple, which is not a thermistor. It does not change resistance with temperature, or at least that's not how it is used to measure temperature - it generates a voltage by the thermocouple effect when two dissimilar metals are joined. Most multimeters use k-type thermocouples. So in this case, it might just be necessary to swap the positive and negative leads of the probe.

Looking at the Toptronic T48, it seems that it uses a proprietary connection for the probe:

https://www.hellermanntyton.co.za/products/digital-multimeters/tbmtempprobe/911-01867

Though, I'm not sure if the website is correct, because I don't see where it plugs into the multimeter:

https://www.hellermanntyton.co.za/products/digital-multimeters/t48/911-00004

According to the manual, it mentions two connections, so I guess the linked probe is not correct.

http://mail.hellermanntyton.co.za/download/manuals/t48-digital-multimeter.pdf

Thank you for replying back to me. When measure resistance on propes only of sensor i.e 105kohms (depends on room temperature). heating sensor resistance drops even if propes are connected in T48 (if  say 19degrees it drops ). Is there a build in sensor in the T48?