As mentioned in our last article, there are things an individual should and should not do when designing thermistor signal conditioning. Do not take thermal conditioning planning lightly because poor thermal conditioning could be detrimental to the devices being created.
What should you do when working with signal conditioning for NTC thermistors?
Take the time to understand your requirements. Of all our tips, this is the one we consider to be the most important. We argue that it is the most critical part of the design process. Three things all engineers should know are: temperature sensing range, temperature sensing accuracy, and temperature sensing resolution. Go through the calculation processes to understand your exact requirements. Accuracy is typically challenging to analyze because of the many factors that contribute to the calculations. Give our team a call to discuss your requirements.
Try to use ratiometric circuits. A ratiometric circuit senses the ratio of currents or voltage, rather than reading absolute values. A Wheatstone bridge and a resistor divider are examples of ratiometric circuits. Sensors that use these circuits are ideal because the accuracy of the quantity being sensed is independent of accuracy voltage/currents references in your circuits.
Treat ADC input channels properly. Do not just connect resistor dividers to an ADC input channel without carefully analyzing what it is installed on. There are two critical characteristics of input channels that all engineers must be aware of: input capacitance and input leakage. Input leakage is considered a parasitic resistance between the circuit nodes and the ADC input.
Be smart and take your time for thermistor signal conditions.
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