What is a common characteristic of an NTC thermistor?

The correct answer highlights that the resistance of an NTC (Negative Temperature Coefficient) thermistor decreases with an increase in temperature. This characteristic is crucial for various applications, particularly in temperature sensing and control within commercial food equipment.

An NTC thermistor operates on the principle that as temperature rises, the movement of charge carriers within the semiconductor material increases, leading to a drop in resistance. This property is widely utilized in temperature measurement devices, as it allows for a clear and predictable change in resistance with temperature fluctuations. For example, when an NTC thermistor is used in a thermostat, it can accurately convey temperature changes, providing necessary feedback for maintaining desired operating conditions in cooking equipment.

The other answer choices describe properties that do not align with the behavior of an NTC thermistor. For instance, the notion that resistance increases with temperature applies to PTC (Positive Temperature Coefficient) thermistors rather than NTC types. Resistance remaining unchanged would suggest a non-thermally-responsive device. Lastly, stating that resistance is always low does not accurately represent the variable nature of an NTC thermistor's resistance based on temperature changes. Thus, understanding the specific behavior of NTC thermistors is essential for applying them effectively in relevant industries.