What is Thermal noise (Johnson noise)?
Noise caused by the thermal motion of electrons in a resistor. Its mean-square voltage is 4kTRΔf, proportional to temperature, resistance and bandwidth.
Thermal noise (Johnson noise) in the explanations
Thermal noise voltage is √(4kTRB), growing with resistance, temperature and bandwidth.
What increases the thermal noise (Johnson noise) voltage ge…The corner frequency where it equals thermal noise can range from kHz to MHz.
Which noise, particularly noticeable in MOSFETs, grows larg…Real ADCs fall short due to thermal noise, distortion and clock jitter, so actual performance is compared by the effective number of bits (ENOB) calculated from measurements.
Which is the approximate formula for the signal-to-noise ra…
Questions that mention Thermal noise (Johnson noise) (5)
- What increases the thermal noise (Johnson noise) voltage generated in a resistor?
- When a voltage is sampled onto a capacitor C through a switch, what is the RMS thermal noise voltage left on the capacitor? (k: Boltzmann constant, T: absolute temperature)
- Which noise, particularly noticeable in MOSFETs, grows larger at lower frequencies?
- Which is the approximate formula for the signal-to-noise ratio (SNR) of an ideal N-bit AD converter, set by quantization noise? (For a full-scale sine-wave input)
- What is the noise called that appears the same way at the same positions every time because of pixel-to-pixel variation in characteristics?
Related terms
Correlated double sampling (CDS) 1/f noise (flicker noise) Jitter ENOB (effective number of bits) Fixed-pattern noise Dark current Bandgap voltage reference CMRR (common-mode rejection ratio) Comparator Cutoff frequency