Thermodynamics of sensors

Markku Ylilammi

    Research output: Contribution to journalArticleScientificpeer-review

    4 Citations (Scopus)


    The process of measurement with a sensor is described in terms of classical thermodynamics. On theoretical grounds, the relevant phenomenon in this context must be a change of state of the system. From the first law of thermodynamics, it follows that sensors are either reversible or irreversible. These classes exhibit some general differences.

    The second law of thermodynamics is applied to a measurement process and a fundamental resolution limitation posed by the available free energy is evaluated. This resolution limit is relevant in very small systems.

    On the basis of the free energy concept, a quantitative definition of conventional signal energy domains is given. This division can be made in various way, but the one chosen here gives a practical method of writing down the relevant equations describing a sensor system.

    By extending classical thermodynamics, the effect of a sensor on the measurement result is estimated at the limit of a slow process.
    Original languageEnglish
    Pages (from-to)167-178
    JournalSensors and Actuators
    Issue number2
    Publication statusPublished - 1989
    MoE publication typeA1 Journal article-refereed


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