Thermocouples calculate temperature. The same thermocouple, cold junction 10, ambient 10. 5

There are many types of thermocouples, and the millivolt value of each model is not the same, and it is not necessarily linear. If you want to calculate the temperature, and assuming you're using a linear thermocouple, you'll need to give at least two millivolts of different temperature measurements to estimate it. Because:

Linear equation: y = ax + b, if a and b can be calculated, then bring in the values of x and y at least twice, e.g. at room temperature 10 °C, millivolt values.

When boiling water at 100 °C, the millivolt value is substituted into the equation: ;. Calculate the values of a and b, and then reverse the substitution:

y will be substituted to calculate the temperature, , x. Hope it works for you.

It is best to determine the index number of the thermocouple, the index number of the thermocouple is not the same, then its millivolt value corresponds to the temperature value is not the same, I checked the boiling water (100) millivolt value for the thermocouple that also conforms to any of the index numbers.

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Hello, the teacher received the question: how to calculate the temperature of the thermocouple, and the answer that the teacher gave you is: the thermocouple calculation method is as follows:

From millivolts to temperature: Measure the cold junction temperature, convert it to the corresponding millivolt value, and add it to the millivolt value of the thermocouple to calculate the temperature. From temperature to millivolts:

The actual temperature and the cold junction temperature are measured, converted to millivolt values respectively, and subtracted to obtain millivolt values, that is, the temperature. Thermocouple is a commonly used temperature measuring element in temperature measuring instruments, which directly measures the temperature and converts the temperature signal into a thermal electromotive force signal, which is converted into the temperature of the measured medium through the electrical instrument (secondary instrument). Hope it helps, dear.

Because the (ambient) temperature change of the cold junction during measurement will seriously affect the accuracy of the measurement, the cold junction temperature compensation is required.

Due to the different materials, different electron densities produce electron diffusion, and when it is stable and equilibrium, an electric potential is generated. When there is a gradient temperature at both ends, there will be an electric current in the loop, generating a thermal electromotive force, and the greater the temperature difference, the greater the current.

The temperature value can be known after measuring the thermal electric positive carrying sock. A thermocouple is actually an energy allowance converter that converts thermal energy into electrical energy.

Technical advantages of thermocouples:

The thermocouple has a wide temperature measurement range and stable performance; High measurement accuracy, the thermocouple is in direct contact with the measured object, and is not affected by the intermediate medium; The thermal response time is fast, and the thermocouple responds flexibly to temperature changes; The measurement range is large, and the thermocouple can be continuously measured from -40 +1600; The thermocouple has reliable performance and good mechanical strength. It has a long service life and is convenient to use.

The galvanic couple must be composed of two conductor materials with different properties but meet certain requirements. There must be a temperature difference between the thermocouple measurement end and the reference end. <>

E(20,0)=, and if the temperature of the hot end is t, the total electric potential is e(t,t0)=e(t,0)-e(t0,0).

So e(t,0) =e(t,t0) +e(t0,0)=

Check the grading table to find t=1188 °C** from the operation gang).

1.Use a K-type thermocouple to measure the temperature, the cold junction temperature of the thermocouple t0=20, and the measured thermoelectric potential is, find.

This problem requires knowledge of the conversion formula of the thermocouple, i.e., the relationship between the thermoelectric potential and the temperature. Specifically, the relationship between the thermoelectric potential e and the temperature t can be expressed as: e = t - t0) where is the thermoelectric coefficient of the thermocouple, t is the hot junction temperature of the thermocouple, and t0 is the cold junction temperature of the thermocouple.

According to the data given in the question, the cold junction temperature t0=20 and the thermoelectric potential e=. Assuming that the thermoelectric coefficient is , the following equation can be listed: = t - 20 ) Solve for :

t - 20) Since the collapse is a problem to solve the temperature t, it is necessary to deform the above equation, which can obtain: t = 20 Therefore, as long as the value of the thermoelectric coefficient is known, the value of the temperature t can be calculated according to the above equation. It should be noted that the value of the thermoelectric coefficient is related to the material and type of thermocouple, and needs to be selected according to the specific experimental conditions.

Summary. Dear students, The thermoelectric potential of the thermocouple is the intermediate temperature law of the thermocouple: the thermoelectric potential between the two contacts (temperature t, t0) of the thermocouple circuit is equal to the algebraic sum of the thermoelectric potential of the thermocouple at the temperature t and tn and the thermoelectric potential at the temperature tn and t0.

tn is called the intermediate temperature. The measured thermal electromotive force is the thermal potential when t, tn, and the thermoelectric potential when tn, t0=40, and the thermoelectric potential of t, t0 is + the corresponding temperature t is (there may be errors, I used software to check).

Dear students, The thermoelectric potential of the thermocouple is the intermediate temperature law of the thermocouple: the thermoelectric potential between the two contacts (the temperature is t, t0) of the thermocouple circuit is equal to the algebraic sum of the thermoelectric potential of the thermoelectric combustion couple at the temperature of t and tn and the thermoelectric potential at the temperature of tn and t0. tn is called the intermediate temperature.

The measured thermoelectromotive force is the thermoelectric potential when t, tn, and the thermoelectric potential when tn, t0=40, the thermoelectric potential of t, t0 is + the corresponding temperature t is (there may be an error, I used the software to check).

Dear students, The thermoelectric potential of the thermocouple is the intermediate temperature law of the thermocouple: the thermoelectric potential between the two contacts (the temperature is t, t0) of the thermocouple circuit is equal to the algebraic sum of the thermocouple's thermal grinding potential at the temperature of t and tn and the thermoelectric potential at the pin leakage temperature of tn and t0. tn is called the intermediate temperature.

The measured thermal electromotive force is the thermal potential at t, tn, and the thermoelectric potential at tn, t0=40, and the thermoelectric potential of t, t0 is + the corresponding temperature t is.

It's amazing, it's amazing.

Dear students, this is what the teacher should do, if you have any questions that you can't do, you can continue to send them to the teacher<>

E(20,0)=, and if the temperature of the hot end is t, the total electric potential is e(t,t0)=e(t,0)-e(t0,0).

So e(t,0) =e(t,t0) +e(t0,0)=

The grading table showed that t = 1188 °C

I don't have a thermoelectric chart on hand, I can only tell you how. One of the basic principles of thermocouple temperature measurement is that the thermoelectric potential is a function of temperature.

Note: Not a function of temperature difference! This means that this is an example of this question:

The electric potential of the cold junction of 25° should be investigated first (the K index should be about 1mv), added to 20mv to get 21mv, and then the temperature corresponding to 21mv should be checked, which is estimated to be about 509°.

If the E-type thermocouple is used for measurement, the thermoelectric potential corresponding to 509° should be checked first, and then the thermoelectric potential corresponding to 25° should be subtracted. You can't use 509° minus 25° first, and then use 509-25=584 to check the thermoelectric comparison table, that's not right.

The cold junction of the type K thermocouple 25 corresponds to a compensation potential of mV

The corresponding temperature is.