Electronics > Beginners
Impeadence matching vs high impeadence buffering?
T3sl4co1l:
Yeah, feedback can skew the small-signal impedance all over the place, but the noise and current remain more or less the same.
Though those can change too, as feedback can have a refrigeration effect on noise sources. I know this... enough to know that it exists; I don't know it well enough to know the practical consequences, or physical limits. So I don't want to make a general statement on it.
Heh, also, exceptions to exceptions always being what they are: your classic noise generators, uA741, LM358 and such, end up with a really high Z_n. Mainly because i_n isn't so crazy, but e_n is just an abomination. :-DD Noise curves (NF vs. Zin) are plotted in AoE3, and LM358 is actually best with a source like 100kohms or so. What a mess!
Tim
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