  Fluctuations of the excess heat in an out of equilibrium steady state are
experimentally investigated in two stochastic systems : an electric circuit
with an imposed mean current and a harmonic oscillator driven out of
equilibrium by a periodic torque. In these two linear systems, we study excess
heat that represents the difference between the dissipated heat out of
equilibrium and the dissipated heat at equilibrium. Fluctuation theorem holds
for the excess heat in the two experimental systems for all observation times
and for all fluctuation magnitudes.
