Re: reduktor szumu analizuje CD krella - Grupy dyskusyjne w eGospodarka.pl

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From: cezar <c...@t...pl.nospam>
Newsgroups: pl.misc.elektronika
Subject: Re: reduktor szumu analizuje CD krella
Date: Tue, 23 Apr 2019 12:24:46 +0100
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[ ukryj nagłówki ]
On 19/04/2019 14:14, J.F. wrote:
> Użytkownik "RoMan Mandziejewicz" napisał w wiadomości grup
> dyskusyjnych:5043293056$2...@s...com.
..
> Hello J.F., Friday, April 19, 2019, 12:39:49 PM, you wrote:
> [...]
>>> -to rownolegle laczenie tranzystorow ... czy to naprawde poprawia
>>> szumy ?
>
>> Tak. Ale bodaj o 3 dB zaledwie.
>
> Czy aby na pewno ?
>
> Bo jak pomyslec ... cztery rownolegle polaczone tranzystory, czy jeden o
> 4x wiekszej powierzchni krzemu ... gdzie tu roznica ?
>
> J.
>
>

takie coś znalazłem - w sumie się zgadza:

If you put "N" transistors in parallel, you effectively put N intrinsic
base resistances rbb in parallel. The rbb of the parallel assembly is
the single transistor rbb, divided by N.

Since voltage noise is proportional to the square root of resistance,
the noise of N transistors in parallel, equals the noise of a single
transistor, divided by sqrt(N).

4 transistors in parallel --> half the noise

9 transistors in parallel --> (1/3) the noise

16 transistors in parallel --> (1/4) the noise

100 transistors in parallel --> (1/10) the noise

900 transistors in parallel --> (1/30) the noise

https://www.diyaudio.com/forums/analog-line-level/27
3001-paralleling-transistors-noise.html

c.