What is a temperature sensor? An analog temperature sensor is pretty easy to explain, its a chip that tells you what the ambient temperature is! These sensors use a solid-state technique to determine the temperature. That is to say, they dont use mercury (like old thermometers), bimetalic strips (like in some home thermometers or stoves), nor do they use thermistors (temperature sensitive resistors). Instead, they use the fact as temperature increases, the votage across .