Noise Calulation in Passive networks

[electronhole]

Hi,

Can any one help me in calculating mean square value of noise voltage in passive circuits (containing R L C only)..Suppose the output of interest is voltage across any one of the capacitor (there may be other capacitors as well)
How can we apply the equipartition law for thermal noise here?

 

[jiripolivka]

Hi,

Can any one help me in calculating mean square value of noise voltage in passive circuits (containing R L C only)..Suppose the output of interest is voltage across any one of the capacitor (there may be other capacitors as well)
How can we apply the equipartition law for thermal noise here?

Only resistors and resistive losses generate thermal noise.
Noise power P = kTB, where
k is the Boltzmann constant, T is the ambient temperature in Kelvins, and B i s the bandwidth in Hz.

Find the book Noise by Van der Ziel, with more details.

 

[electronhole]

yes i know this.I am asking how to apply the equipartition of thermal noise when there are more than one capacitors in the circuit

 

[jiripolivka]

yes i know this.I am asking how to apply the equipartition of thermal noise when there are more than one capacitors in the circuit

Only the resistive leakage loss in capacitors generates thermal noise power. But capacitors and inductors affect the structure bandwidth.

More details in Vander Ziel's book "Noise"

 

[electronhole]

Say I have a capacitor and resistor,
then 1/2 CV^2 = 1/2 kT. right? where V^2 is the mean squared noise voltage across the capacitor. I wan t to how this equation is modified in case there are many resistors and capacitors..so that one can calculate the mean squared noise voltage across the each individual capacitor