Question:
Published on: 20 June, 2022

An amplifier operating over the frequency range from 8 MHz to 20 MHz has a 10 kΩ input resistor. What is the r.m.s noise voltage at the input to this amplifier if the ambient temperature is $${27}^0C$$?

Given that,

$$k=Boltzmann^\prime s constant=1.38\times{10}^{-23}\frac{Joules}{Kelvin}$$

$$T=Temperatureoftheconductor\in Kelvin=\left(27+273\right)=300K$$

$$B=Bandwidthofthenoisespectrum=\left(20-8\right)=12MHz$$

$$R=10K\mathrm{\Omega}$$

The r.m.s input noise power of the amplifier is

$$\sqrt{4kTBR}=\sqrt{4\times1.38\times{10}^{-23}\times300\times12\times{10}^6\times10\times{10}^3}=37.95µV$$

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