A thermistor is a type of temperature sensor made from ceramic materials that change their resistance with temperature variations. There are two main types: negative temperature coefficient (NTC) thermistors, which decrease in resistance as temperature increases, and positive temperature coefficient (PTC) thermistors, which increase in resistance with rising temperature. These properties make thermistors useful in various applications, including temperature measurement and control. Thermistors are commonly used in electronic devices, such as thermostats, digital thermometers, and automotive systems. They provide accurate temperature readings and can help regulate heating and cooling systems. Their compact size and quick response time make them ideal for many consumer and industrial applications.