J Type Thermocouple or RTD? 3 Wires: 2 White, 1 Red—How to Identify Sensor Type

Hi,I have a very basic doubt regarding standard J type thermocouple temperature sensor,according to my knowledge thermocouple has two outlets i.e +ve and- ve but in my case i have 3 wires where 2 comes in white and one more in red,so i have a doubt whether it is a thermocouple or it is a RTD? plz answer me regarding this and it will be helpful if i get the answer ASAP.
Thanks.

Sounds like an RTD, check with an ohm meter. Rtd's can come in 2, 3 or 4 wire wire,
cheers,
Richard

thanks Richard

Looks like RTD. It works by sending a known amount of current through the RTD sensor and then measuring the voltage drop across that resistor at a given temperature.

Based on the 3 wires you describe for your temperature sensor, it does sound like you likely have a RTD (Resistance Temperature Detector) rather than a thermocouple. Here are a few points that indicate it is probably a RTD:

RTDs usually have 3 wires - two for the sensor loop current and a third for compensation. Thermocouples only need two wires.
You mentioned two white wires - RTDs often use the same wire color for the main sensor leads. Thermocouples use different metals.
The third red wire is likely the compensation lead that RTDs use to account for lead resistance. Not needed for thermocouples.
RTDs provide more stable and accurate temperature measurements compared to thermocouples. The third wire helps with this.
To confirm, you would need to check the sensor specs and wiring diagram from the manufacturer documentation. But based on the 3-wire connection and same-colored leads, it fits the profile of a common PT100 or PT1000 RTD sensor.