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I. Preface
This is an infrared temperature measurement module, and the day before yesterday a USB interface and LED display were made for it, which can automatically read the measured temperature by the computer. The following temperature measurement of the thin film coil includes this high-precision current-sensing resistor. They are supplied with different currents and the corresponding temperature is measured. The DH1766 DC power supply is programmed to provide different currents. Take a look at the temperature changes of the coil and resistor.
Second, the temperature of the coil
Hold the temperature sensor close to the coil. The DG1766 is utilized to give currents from 0 to 1A. In this process, the temperature of the coil is measured. Each time the current is changed, hold it for 2 seconds, and then read the corresponding temperature. The measurement results show that the temperature rise is approximately a quadratic function. That is, as the current increases, the temperature rises faster and faster.
▲ Figure 1.2.1 Measurement results
This is a quadratic curve that fits the measurements, and you can see that there is a very high degree of agreement between them. From this, it can be seen that the temperature of the coil is basically proportional to its heat dissipation power, and also proportional to the square of the current flowing.
▲ Figure 1.2.2 Quadratic curve fitting
3. High-precision resistance
Measure the relationship between temperature and current at a 5 ohm high-precision current-sensing resistor. The current varies from 0 to 0.5A, and the corresponding temperature at each current is measured. This is the result of the measurement. From the point of view of the fitting curve, it seems that there is a bit of a problem, that is, when you start again, the temperature drops. This is supposed to be caused by the fact that the resistance has been heated before the measurement is made, and it has not been able to be lowered to room temperature to start a new measurement.
▲ Figure 1.3.1 The temperature measurement module displays the temperature
▲ Figure 1.3.2 Measurement results
▲ Figure 1.3.3 Quadratic curve fitting results
To do this, re-measure. This time it's been ten minutes since the last measurement, and it feels like the temperature should have been lowered to room temperature. The data fits well, but it seems that the quadratic curve shows that the lowest temperature still occurs at 0.1A. It's weird.
▲ Figure 1.3.4 Remeasurement results
▲ Figure 1.3.5 Fitting results
※Summary※
In this paper, the temperature of the current sensing resistor and the thin film coil is measured using the LU90614 infrared temperature measurement module. The rise in temperature is approximately proportional to the power of the current.