Difference between revisions of "Resistor Noise"
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{{NumBlk|::|<math>\overline{i^2_n} = 4kTGB = \frac{4kTB}{R}</math>|{{EquationRef|2}}}} | {{NumBlk|::|<math>\overline{i^2_n} = 4kTGB = \frac{4kTB}{R}</math>|{{EquationRef|2}}}} | ||
| − | Where <math>k</math> is Boltzmann's constant, equal to <math>8.617 \times 10^{-5}\mathrm{\tfrac{eV}{K}}</math>, and <math>B</math> is the observation bandwidth. | + | Where <math>k</math> is Boltzmann's constant, equal to <math>8.617 \times 10^{-5}\mathrm{\tfrac{eV}{K}}</math>, and <math>B</math> is the observation bandwidth. Thermal noise has a ''white'' power spectral density, as shown in Fig. 2. |
== Noise in Resistor Circuits == | == Noise in Resistor Circuits == | ||
Revision as of 01:36, 5 October 2020
Due to the random thermal motion of charge carriers, we observe thermal noise, voltage and current noise in resistive circuit elements that is proportional to absolute temperature.
Modeling Thermal Noise in Resistors
Consider the noisy resistor in Fig. 1. We can model this as a noiseless resistor in series with a voltage noise generator, or a noiseless resistor in parallel with a current noise generator. Since we cannot predict the voltage or current noise at any point in time, we instead specify the noise voltage or current power:
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(1)
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(2)
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Where is Boltzmann's constant, equal to , and is the observation bandwidth. Thermal noise has a white power spectral density, as shown in Fig. 2.
