Johnson-Nyquist noise (sometimes only "Nyquist noise") is the
equilibrium fluctuations of the
electric current inside an
electrical conductor, which happen without any applied
voltage, due to the random thermal motion of the charge carriers (the
electrons).
It is to be distinguished from Shot noise, which describes the additional current fluctuations that occur when a voltage is applied and a macroscopic current starts to flow.
The strength of Nyquist noise is related to the temperature and the resistance of the conductor.
See: Harry Nyquist, J. Johnson
- J. Johnson, "Thermal Agitation of Electricity in Conductors", Phys. Rev. 32, 97 (1928) -- the experiment
- H. Nyquist, "Thermal Agitation of Electric Charge in Conductors", Phys. Rev. 32, 110 (1928) -- the theory
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