We studied experimentally the thermal noise in a resistor and found that the spectral density of the fluctuating voltage across it depends linearly on the temperature, as predicted by Nyquist, and provides an approximate value for Boltzmann's constant. Our result, factoring in the small error in the amplifier gain, was kB= 1.63(14) x 10-23 J/K, in good agreement with the reference value within two standard-deviations. The experiment described to study Johnson noise is probably hindered by a systematic error source that we were unable to properly identify.

Other possible directions of study could include a test of the relation of SV with resistance, and possible variation with the type of resistive material used.

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