"Jim Thompson"


** Hmmm .....

Input noise is shown 1.136 nV across the audio band.

Multiply by 141 ( ie sq.rt 20,000 ) = 160 nV.

The self noise of a 200 ohm source = 240 nV.

Gives a total noise = 288 nV.

Just a bit more than " project 66 " tests at 270 uV.

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The gain graph shows the figure is close to 59 dB.

Just one hour after Jim posed his Q about a gain equation

- I posted this in reply :


" ** The overall gain is: 6.82 times 4000 / Rg "


In this example, Rg = 27 + 4 = 31 ohms

So the predicted voltage gain = 880 times.

Makes the gain 58.9 dB.




....... Phil