The concept of shot noise was first introduced in 1988 by Walter Schottky who described the noise generated in the form of Poisson Statistics. The Poisson Statistics show that the randomized fluctuation in the number of charges in a DC current are significant and not ignorable. Instead, these fluctuations are measurable and produce the charge of an electron if measured correctly. Schottky’s prediction of a fundamental relation between the size of the fluctuations \(<\delta i^2(t)>\) in a current of uncorrelated (randomly emitted) electrons of average magnitude \(i_{dc}\) and the amount of charge \(e\) carried by an individual electron in that current is:
\[\label{eq:SchottkyPredictionForShotNoise2} <\delta i^2(t)> = (2 e) \left(i_{\textrm{dc}} \Delta f \right).\]
where \(\Delta f\) is the ENBW, as before, and allows you to determine \(e\) from measurements of \(<\delta i^2(t)>\) and \(i_{dc}\).