Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.

Temperature (K)

Required number input.

Resistance (Ω)

Required number input.

Bandwidth (Hz)

Required number input.

Compute the RMS Johnson-Nyquist noise voltage of a resistor in nanovolts over a measurement bandwidth. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Noise voltage (nV)

The resulting noise voltage returned as a number.

• Resistor value, power, noise, and color-code calculations must account for tolerance, temperature coefficient, voltage coefficient, pulse rating, working voltage, package thermal resistance, ambient temperature, and mounting. Required steady-state power should include the manufacturer's derating curve.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.

• Resistor Thermal Noise Current

  RMS Johnson-Nyquist current noise over an equivalent noise bandwidth; assumes a resistor at thermal equilibrium.

• Accelerometer Noise Density

  Infer white accelerometer noise density from measured RMS noise and equivalent noise bandwidth; colored noise needs spectral analysis.

• ADC Total Harmonic Distortion

  Calculate THD from RMS harmonic amplitudes relative to the fundamental: sqrt(sum of harmonic squares)/fundamental. Output is percent and dBc; include only the harmonics specified by the measurement method, excluding noise and DC.