NTC thermistor test precautions.Radar Microwave Induction Sensor Switch manufacture

　　The resistance at a given temperature is usually impregnated with NTC thermistor in the liquid bath that is not controlled by the controlled temperature, and then measures its resistance. Usually, it does not use the gas chamber because they are difficult to stabilize and control. How to accurately control the bath temperature?

　　It is assumed that 5%thermistor is required to double the ALPHA value of 4.4%/° C under 25 ° C. 5%resistance tolerance is equal to the temperature tolerance of equivalent. 5%divide by 4.4%/c ° = 1.2 C ° According to experience, the error error of the plating fluid should not be greater than one tenth of the .1 C °. If the temperature tolerance of the thermistor is 0.02 ° C, the melting tank must be able to reach 0.02 ° C. It should be noted that due to the error of the resistance, the limit of the heat sensitivity of the resistance is correct. The bathroom, and the ratio of 5%can be confused with a ratio of 5.5%. In the example of .2c °, it may be mistaken for .22 C °. Naturally, bathroom errors sometimes make the thermistor resistance more satisfactory. If this is unacceptable, two things can be done. Or control the accuracy of the bath tank at the acceptable level, otherwise, the actual temperature of the bath tank must be displayed during measurement. In order to correct the temperature, the error is converted to an equivalent resistance with Alpha and A, and the number of resistance reading is reduced from the original value as needed.

　　Correct temperature may have its trap. The temperature in all control thermal systems tends to fluctuate or circulate within the narrow temperature range called system bandwidth. It can also be called "bathroom autumn". In order to minimize this impact, the operator can wait until the temperature reaches the required temperature, and then quickly obtain the number of resistance reading.

　　If the temperature is within 1 minute, the oscillation speed will not exceed one tenth or tenth.

　　However, there are two characteristics of attention: First, according to the structure size, materials and thermal quality measurement independent temperature indicators and resistance thermistor. Otherwise, these two devices will not follow or follow each other. Big or larger equipment will delay temperature. The second point is that temperature fluctuation tends to focus on the required test temperature. As a result, although the number of resistance reads clearly under the accurate required temperature, this is also the focus of the cycle. The cycle changes at the fastest speed as a reference to allow oscillation to the maximum range in one direction (in bandwidth in bandwidth (in bandwidth The edge of the system), this will be the most stable point. In fact, the speed of the torque is almost zero, but the temperature is far from the required temperature.

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