How accurate is thermometer for measuring component temperature?

[Flyback]

How accurate is this thermometer for getting temperature of ....

a ferrite inductor.
a heatsink thats bare aluminium
a heatsink thats anodised aluminium (black)
an electrolytic capacitor.
a mosfet case (the black body of a to220)

Thermometer.
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(Maplin N92FX)

 

[kubeek]

Probably pretty hopeless, those parts are fairly small, and the thermometer will average out the whole area it "sees". Much better would be a small thermocouple that you could put right on the surface of the part you want to measure.

 

[MikeMl]

I have even a cheaper, smaller version of an IR thermometer. I find it very useful for finding hot spots on a PCB. Its field of view is about 45deg.

 

[Mr RB]

Most IR thermometers are pretty good and will measure the hottest thing in view, which is usually the innards of the component. If you want to measure the outer case temperature you need a contact type thermometer.

 

[crutschow]

Most IR thermometers are pretty good and will measure the hottest thing in view, which is usually the innards of the component. If you want to measure the outer case temperature you need a contact type thermometer.

Not true unless the package is transparent to IR, and no common package types are. IR radiates from the surface of an object, so you will be seeing the package surface temperature, not the inside temperature (contrary to the special effects in the movies and TV where they magically see the IR image of someone through solid walls. That never can happen. )

 

[debe]

This works for me on small objects.

 

[Mr RB]

Not true unless the package is transparent to IR, and no common package types are. IR radiates from the surface of an object, so you will be seeing the package surface temperature, not the inside temperature (contrary to the special effects in the movies and TV where they magically see the IR image of someone through solid walls. That never can happen. )

IR is the long wavelength and many materials are fairly transmissive of IR. The black stuff they make IC and transistor bodies out of is a good IR conductor and quite transmissive to IR;

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(You can see the actual silicon chip inside the package and the temperature of the silicon.)

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