• JustEnoughDucks@feddit.nl
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    3 days ago

    So this is a 3D printed PTC thermistor. Very cool and potentially extremely useful for measuring temperatures within a housing which has never before been able to be done to my knowledge. This is potentially awesome for embedding in medical devices which by regulations cannot be above a specific temperature while in contact with the body.

    That said, there is nothing “active” about it. Thermistors are, by definition, passive electronic components. Actives amplify, rectify, or supply electric energy while passives consume, store, and release supplied energy.

    • HewlettHackard@lemmy.ca
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      4 hours ago

      Couldn’t you build an amplifier by using a thin wire that heats up a larger wire? If you size the large wire to minimize self heating, then a small current would cause the thin wire to act as a heater, switching the large current.

      • JustEnoughDucks@feddit.nl
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        3 hours ago

        Well yeah, you could do that with any PTC + resistor. That is then a circuit, not an active component. Also you would likely have to use more energy than you would gain from “amplifying” since the heat would conduct away from the target and radiate away.

        For example, if you had a photoresistor and used an LED to turn its resistance from high to low, that doesn’t make the photoresistor an active component.

        Plus in the paper, the small wire + geometry is a prerequisite to do the resistance switch without melting everything.