#### Packo_z007

##### Newbie level 3

Hi there - I'm new around here and I'm looking for help with this circuit.

This is a thermocouple circuit which makes the cold junction compensation using the 1N4148 diode. I can understand almost everything about it but the function of the R4 resistor. Can someone help me with this? Thank you.

Edit:

I'm working on this project with a friend of mine and we already made some tests trying to figure out this. Today we measured the voltage on the thermocouple terminals with the hot junction at 0ºC and the cold junction at 30ºC. The read was -1.18mV which is fine. Then we took out the R4 resistor and our measurement was -1.16mV. We tested it three times. The point is that if the resistor is a load to the thermocouple, taking it out the voltage should go up.

This is a thermocouple circuit which makes the cold junction compensation using the 1N4148 diode. I can understand almost everything about it but the function of the R4 resistor. Can someone help me with this? Thank you.

Edit:

I'm working on this project with a friend of mine and we already made some tests trying to figure out this. Today we measured the voltage on the thermocouple terminals with the hot junction at 0ºC and the cold junction at 30ºC. The read was -1.18mV which is fine. Then we took out the R4 resistor and our measurement was -1.16mV. We tested it three times. The point is that if the resistor is a load to the thermocouple, taking it out the voltage should go up.

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