The mean- square open- circuit voltage (e) across a resistor (R) is:
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1 The mean- square open- circuit voltage (e) across a resistor (R) is: e n = √ (4kT K RΔf) where: T K is Temperature (ºK) R is Resistance (Ω) f is frequency (Hz) k is Boltzmann’s constant (1.381E-23 joule/ºK) e n is volts (V RMS ) To convert Temperature Kelvin to T K = 273.15 o C + T C Thermal Noise Random motion of charges generate noise
description
Thermal Noise. The mean- square open- circuit voltage (e) across a resistor (R) is: e n = √ (4kT K RΔf) where: T K is Temperature (ºK) R is Resistance (Ω) f is frequency (Hz) k is Boltzmann’s constant - PowerPoint PPT Presentation
Transcript of The mean- square open- circuit voltage (e) across a resistor (R) is:
1
The mean- square open- circuit voltage (e) across a resistor (R) is:
en = √ (4kTKRΔf) where: TK is Temperature (ºK) R is Resistance (Ω) f is frequency (Hz) k is Boltzmann’s constant
(1.381E-23 joule/ºK) en is volts (VRMS)
To convert Temperature Kelvin to
TK = 273.15oC + TC
Thermal Noise
Random motion of charges generate noise
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Noise Spectral Density vs. Resistance
Resistance (Ohms)
Noi
se S
pect
ral D
ensi
ty v
s. R
esist
ance
nV/r
t-H
z
10 100 1 10 3 1 10 4 1 10 5 1 10 6 1 10 70.1
1
10
100
1 10 3468.916
0.347
4 1.38065 1023 25 273.15( ) X 10
9
4 1.38065 1023 125 273.15( ) X 10
9
4 1.38065 1023 55 273.15( ) X 10
9
10710 X
1000
10 100 1 103 1 104 1 105 1 106 1 1070.1
1
10
100
1 103468.916
0.347
4 1.380651023 25 273.15( ) X 10
9
4 1.380651023 125 273.15( ) X 109
4 1.380651023 55 273.15( ) X 109
10710 X
25C
125C
-55C
Thermal Noise
en density = √ (4kTKR)
Resistance versus Spectral Density
