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Thread: MCP9808 temperature sensor

  1. #1
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    MCP9808 temperature sensor

    Hi
    While I was testing the mcp9808 temperature sensor with teensy using an example program, It was very slow in responding to the change in temperature. For example it is taking long to change its temperature from normal to freezing. Does anyone have any idea about this issue?

  2. #2
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    Hi Anna,

    How long is it taking to fully change temperature?

    All the best,

    Alan

  3. #3
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    Quote Originally Posted by AlanK View Post
    Hi Anna,

    How long is it taking to fully change temperature?

    All the best,

    Alan
    It took almost 10 minutes to change from 20degree celsius to 9 degree celsius

  4. #4
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    Heat is slow unless you use metal. This device has a thermal pad designed to be soldered to a PCB substrate PCB or similar for fast
    thermal response.

    Something in an epoxy package on a PCB sitting in still air will indeed take ages to change temperature, the whole PCB will have
    thermal mass and still air is a pretty good thermal insulator.

    The speed of heat spreading in many plastics or wood etc is about 1000 times slower than in copper, for instance.

  5. #5
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    Hi Anna,

    That sounds reasonable for that chip.

    If you want a faster response then you need to look at the thermal setup - using the thermal pad on the chip and perhaps forcing air past it if you are measuring air temperature. No matter what you do with it, however, you're limited by the thermal capacitance and resistance of the device - if you need a much faster response then you'll need to use a different type of sensor,
    All the best,
    Alan

  6. #6
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    Thin film thermistors are fast, as can be thermocouples (small dimensions means short thermal path, low thermal mass).

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