Fundamental Noise:

arising from Second Law of Thermodynamics (Johnson Noise),

arising from Quantization of Electrical Charge (Shot Noise – Schrotrauschen).

Measure possible fundamental constants:

Boltzmann constant (from Johnson white noise of resistors’ voltage)

Charge of Electron (from Shot Noise of a photocurrent)

Protocol

Recording of Noise Samples

Variation of Noise (table)

Dependence on Resistance (3 resistors)

Dependence on Bandwidth (twenty of more combinations)

Calculation of Boltzmann’s constant

Interpolation of absolute zero

No theory. Estimate errors.

Johnson Noise

⟨⟩ for time average

⟨U²⟩ = 4 k R T ∆f

Noise is equally composed of all frequencies (compare blackbody radiation).

V_meter = ⟨U²⟩ (600 300)²/(10 V)

In practice, there’s an extra ⟨V_N²⟩ added to this. Measure V_N by using a very small resistor (1 ohm) and very small bandwidth and thus very small U.

V_meter = (600 300)² (⟨U²⟩ + ⟨V_N²⟩)/(10 V)

10 V V_meter/(600 300)²  = ⟨U²⟩ + ⟨V_N²⟩

Bandwidth is (0.1 .. 100) kHz

Sources Of Error

Resistor tolerances

Amplifier nonlinearity

Temperature instability

Filter effective bandwidth uncertainities

Systematic effects (A.8) capacitive effects