Modifications

An analog temperature sensor is pretty easy to explain, its a chip that tells you what the ambient temperature is!

An analog temperature sensor is pretty easy to explain, its a chip that tells you what the ambient temperature is!

[[Fichier:TMP36-intro.jpg]]

[[Fichier:TMP36-intro.jpg|250px]]

These sensors use a solid-state technique to determine the temperature. That is to say, they don't use mercury (like old thermometers), [http://en.wikipedia.org/wiki/Bimetallic_strip bimetalic strips] (like in some home thermometers or stoves), nor do they use [http://en.wikipedia.org/wiki/Thermistor thermistors] (temperature sensitive resistors). Instead, they use the fact as temperature increases, the voltage across a diode increases at a known rate. (Technically, this is actually the voltage drop between the base and emitter - the Vbe - of a transistor.) By precisely amplifying the voltage change, it is easy to generate an analog signal that is directly proportional to temperature. There have been some improvements on the technique but, essentially that is how temperature is measured.

These sensors use a solid-state technique to determine the temperature. That is to say, they don't use mercury (like old thermometers), [http://en.wikipedia.org/wiki/Bimetallic_strip bimetalic strips] (like in some home thermometers or stoves), nor do they use [http://en.wikipedia.org/wiki/Thermistor thermistors] (temperature sensitive resistors). Instead, they use the fact as temperature increases, the voltage across a diode increases at a known rate. (Technically, this is actually the voltage drop between the base and emitter - the Vbe - of a transistor.) By precisely amplifying the voltage change, it is easy to generate an analog signal that is directly proportional to temperature. There have been some improvements on the technique but, essentially that is how temperature is measured.