Calculates the root mean square value of the Noise Voltage VN(rms) at the Output of an Emitter follower [Common Collector Amplifier] ~ Are emitter followers noisy when used as input to pre-amplifiers ? ~ If the output impedance presented to the next stage is lower than RS but the SNR is not affected very much is this an advantage ?
The Calculation does not take into account flicker noise and assumes perfect resistive loads and a modern silicon transistor with low noise bias and the transistor gain is constant within the measurement bandwidth defined
The circled nodes B C and E represent the external connections of the transistor and lower case rbb and re are internal resistances ~ The output resistance ro is included in calculation but if not known assume its value is >1MΩ although for some PNP transistors it may be much lower
Start by entering a Collector Current and change variables as required
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See these references for more about transistor noise :
The Art of Electronics 3rd edition chapter 8 ~ By Paul Horowitz and Winfield Hill
Noise in Transistor Circuits ~ By P. J. Baxandall ~ Wireless World November 1968
Designing low–noise audio amplifiers ~ By Wilfried Adam ~ Wireless World June 1989
Introduction to low–noise amplifier design ~ By A. Foord ~ Wireless World April 1981
The design of Low-noise audio frequency amplifiers ~ By E. A. Faulkner ~ The Radio and Electronic Engineer July 1968 ~ This excellent article along with the book 'Low-Noise Electronic System Design' By C. D. Motchenbacher and J. A. Connelly should answer most questions about electronic noise
" Do you work it out one by one ~ Or played in combination "