Conditioning Thermistor Signals: What Not to Do

When using an NTC thermistor, it is crucial to understand how the conditioning thermistor signals work. One must follow extremely specific guidelines when working with thermistors. Certain things should never be done by the operator when it comes to conditioning thermistor signals.

When it comes to conditioning thermistor signals, you should never linearize your analog circuitry. Linearization is the use of additional circuitry. The additional circuitry is used to produce a voltage that is a more linear function of temperature.

Linearization is necessary for purely analog circuits. This process is often done using a thermistor. The nonlinear response of the thermistor must be conditioned into a linear adjustment to the thermocouple amplifier.

When working with an embedded system, such as conditioning thermistor signals, the operator should not do the linearization in software. There are much simpler ways to maintain the nonlinear conversion of ADC counts to temperature.

One more thing that the operator should never do when dealing with conditioning thermistor signals is not to use excess signal conditioning. Using signal conditioning should be a simple process. There is no need to make it more complicated than it should be.

Things should be kept simple, you should use good components, and you should design carefully. If you do not follow these steps, you will find it difficult to have net voltage errors below 1% of the ADC full scale.

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