The sensor is indicating that the temperature is 26.3☌ also known as 79.3☏ Note that if you're using a LM35, the voltage will be 0.25V If you've got a TMP36 and its about room temperature (25☌), the voltage should be about 0.75V. Then connect your multimeter in DC voltage mode to ground and the remaining pin 2 (middle). Testing these sensors is pretty easy but you'll need a battery pack or power supply.Ĭonnect a 2.7-5.5V power supply (2-4 AA batteries work fantastic) so that ground is connected to pin 3 (right pin), and power is connected to pin 1 (left pin) Moreover they are very inexpensive and quite easy to use There have been some improvements on the technique but, essentially that is how temperature is measured.īecause these sensors have no moving parts, they are precise, never wear out, don't need calibration, work under many environmental conditions, and are consistant between sensors and readings.
By precisely amplifying the voltage change, it is easy to genereate an analog signal that is directly proportional to temperature. (Technically, this is actually the voltage drop between the base and emitter - the Vbe - of a transistor. Instead, they use the fact as temperature increases, the votage across a diode increases at a known rate. 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). These sensors use a solid-state technique to determine the temperature. An analog temperature sensor is pretty easy to explain, its a chip that tells you what the ambient temperature is!
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