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    Thermal camera reading fet temperatures...how far away to hold it?

    For assessing the temperature of FETs on the PCB, how far away from the fet should this thermal camera (HT-04) be held?
    The spec appears to suggest 32 inches away?

    We do notice that the temperature reading varies as we move the camera nearer/further from the fet.

    https://www.fasttech.com/product/966...imaging-camera

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    Re: Thermal camera reading fet temperatures...how far away to hold it?

    The reading should not vary over distance, but small objects may not correctly focussed. The manual says fixed focus and 0.15 m minimal focus length, not sure if it's correct.

    I would check what the actual focus is and also check the reading with a large object at homogenous temperature.

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    Re: Thermal camera reading fet temperatures...how far away to hold it?

    The spec appears to suggest 32 inches away?
    The specifications says:

    "Field Angle / Shortest Focal Length: 27'35'/0.5m
    Thermal Sensitivity: 0.07'C
    Measuring Mode: Thermopile
    Temperature Range: -20'C to 300'C(-4'F to 572'F)
    Measuring Accuracy: 2.5'C or 2.5%
    Emissivity: Adjustable from 0.1 to 1.0
    Image Frequency: 8Hz
    Wavelength Range: 8-14μm
    Focus Mode: Fixed"

    You need to bring the camera close enough so that the object of interest has some significant size in the screen. I guess the temp is computed for every 4X4 pixel (not so sure).

    The temp can be off by +/- 2.5C or +/-2.5% (this must be referring to absolute temp; that can mean different- again you should see the detailed manual).

    Just test with a small piece of ice on a kitchen sink!

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