[EFM] What EFM designs can be run from +9 volt supply?

[René Schmitz]

At 22:16 15.07.00 -0400, Harry Bissell wrote:
>Hi Rene (et al)
>
>I don't think this will work... the input impedance is probably way too low.
>OK for that transformer driven amp, but for a filter readout I'm not so sure.

The impedance of the readout in the vcf6 is 100k.

>The LM3900 inputs look kind of like a diode drop (hey... maybe 2...) to the
>negative rail. Even with a blocking cap that would be really low...

Erm, there are two resistors in series, and these determine the input
impedance.
(Ok, only 10k in this case.) If one makes all resistors ten times as large
you have the same impedances like in the opamp circuit.

Bye,
 René

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uzs159 at uni-bonn.de
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