Thermistor is a transducer. Its commonly used temperature coefficient is a. Negative c. Zero b. Positive d. None of these
The correct answer and explanation is:
The correct answer is a. Negative.
A thermistor is a type of resistor whose resistance changes significantly with temperature. It is commonly used as a transducer in various temperature sensing applications. The temperature coefficient of a thermistor refers to the direction in which its resistance changes as the temperature changes.
There are two primary types of thermistors based on their temperature coefficient: Negative Temperature Coefficient (NTC) and Positive Temperature Coefficient (PTC).
- NTC thermistors have a negative temperature coefficient, meaning their resistance decreases as the temperature increases. This characteristic makes NTC thermistors ideal for applications where the resistance needs to decrease with increasing temperature, such as temperature sensors in devices like thermometers, thermostats, and temperature control systems. In NTC thermistors, the decrease in resistance with temperature is due to the increase in the number of charge carriers (electrons) that are freed from their bonds as temperature rises, which facilitates the conduction of electricity.
- PTC thermistors, on the other hand, have a positive temperature coefficient, meaning their resistance increases with temperature. PTC thermistors are often used for overcurrent protection, as their resistance increases when the current increases, thereby limiting the flow of current and protecting the circuit from damage.
The zero temperature coefficient is rare in thermistors. This would indicate no change in resistance with temperature, which is not a typical characteristic of thermistors.
In summary, the most common type of thermistor, especially for temperature sensing applications, has a negative temperature coefficient (NTC). This property is essential in various industrial, medical, and electronic devices, making NTC thermistors widely used in temperature measurement and control systems.