Johnson and Shot Noise. First Draft

Abstract

Two sources of noise, Johnson noise and shot noise, are investigated in this experiment. The Johnson noise which is the voltage fluctuations across a resistor that arose from the random motion of electrons. It was measured across different resistances and at different bandwidths at room temperature, resulting in a calculation of the Boltzmann constant of \(1.46 \cdot 10^{-23} \textrm{ m}^2 \textrm{ kg} \textrm{ s}^{-2} \textrm{ K}^{-1} \pm2.5 \cdot 10^{-21} \textrm{ m}^2 \textrm{ kg} \textrm{ s}^{-2} \textrm{ K}^{-1}\) and \(1.46 \cdot 10^{-23} \textrm{ m}^2 \textrm{ kg} \textrm{ s}^{-2} \textrm{ K}^{-1} \pm2.6 \cdot 10^{-21} \textrm{ m}^2 \textrm{ kg} \textrm{ s}^{-2} \textrm{ K}^{-1}\). The shot noise occurs due to the quantization of charge, and was measured by varying current in the system, with which we calculated the electron charge of \(1.64 \cdot 10^{-19} \pm 7.0 \cdot 10^{ -22}\). They agree quite well with the accepted values of \(1.38064852 \cdot 10^{-23} \textrm{ m}^2 \textrm{ kg} \textrm{ s}^{-2} \textrm{ K}^{-1}\), and \(1.64 \cdot 10^{-19} \textrm{C}\) for the Boltzmann constant and electron charge respectively. Errors are discussed.