  In this brief note, we demonstrate a generalised energy equipartition theorem
for a generic electrical circuit with Johnson-Nyquist (thermal) noise. From
quantum mechanical considerations, the thermal modes have an energy
distribution dictated by Planck's law. For a resistive circuit with some
inductance, it is shown that the real part of the admittance is proportional to
a probability distribution function which modulates the contributions to the
system's mean energy from various frequencies of the Fourier spectrum. Further,
we analyse the case with a capacitor connected in series with an inductor and a
resistor. The results resemble superstatistics, i.e. a superposition of two
statistics and can be reformulated in the energy representation. The correct
classical limit is obtained as $\hbar \rightarrow 0$.
