Jinx wrote:
>> Yeah, I know, but all I have on hand are some 741's, 748's,
>> and 393's. Would one of the others be a better choice?
>> Operating on a shoestring here.  ;-)
>
> A 393 will go down to 2V. It's designed as a comparator but
> you may be able to use some feedback to get it acting more
> like an op amp. If the signal is big and clean enough though
> you could use it as a comparator to square up and amplify
> the 40kHz

I think I'll experiment with using this to follow the 741 as I need a
bit more gain than I currently have, and this should work nicely.

> As an exercise in frivolity, how about using one of the 741s
> you've got lying around to make a charge pump (oscillator +
> diode-capacitor doubler) to give you 9V for the input stage
> 741 ?

Isn't that what the extra outputs on a MAX232 are for?  ;-)

michael

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