  The measurement of thermal fluctuations provides information about the
microscopic state of a thermodynamic system and can be used in order to extract
work from a single heat bath in a suitable cyclic process. We present a minimal
framework for the modeling of a measurement device and we propose a protocol
for the measurement of thermal fluctuations. In this framework, the measurement
of thermal fluctuations naturally leads to the dissipation of work. We
illustrate this framework on a simple two states system inspired by the
Szilard's information engine.
