telegraphic
May2-10, 01:45 PM
Hi all -- I had a question about the Nyquist-Johnson noise formula:
\[
E_{\nu}^{2}d\nu=\frac{4R_{\nu}hd\nu}{e^{h\nu/kT}-1}\]
which of course can be approximated for most purposes as $ E_{\nu}^{2}d\nu=4R_{\nu}kTd\nu$.
I'm just wondering why the formula has $ exp(h\nu/kT)-1$ in the denominator? I would have expected $ exp(h\nu/kT)+1$ as electrons are fermions, so obey Fermi-Dirac statistics as opposed to Bose-Einstein. Sure I'm missing something obvious!
Cheers
\[
E_{\nu}^{2}d\nu=\frac{4R_{\nu}hd\nu}{e^{h\nu/kT}-1}\]
which of course can be approximated for most purposes as $ E_{\nu}^{2}d\nu=4R_{\nu}kTd\nu$.
I'm just wondering why the formula has $ exp(h\nu/kT)-1$ in the denominator? I would have expected $ exp(h\nu/kT)+1$ as electrons are fermions, so obey Fermi-Dirac statistics as opposed to Bose-Einstein. Sure I'm missing something obvious!
Cheers