[sdiy] integrator / capacitor leakage

[JH.]

Polystyrene is no problem.
So, same configuration, same type of capacitor, what would be better?
C/10, or level/10 + amplification?

JH.


> imho the weak link is the capacitor...
>
> if the 'smaller' cap allows you to get into a high-quality type
> like a polystyrene, I'd go that direction.  Its hard to get large
> value, low leakage caps.
>
> Good amplifiers are easier to find.
>
> H^) harry
>
>
>
> jhaible at debitel.net wrote:
>
> > When I'm building an integrator for a triangle or sine wave oscillator
with an
> > amplitude of 20Vpp, I have two options:
> >
> > a) run the integrator at 20Vpp, or
> > b) run the integrator at a lower voltage, and amplify the signal
> >    with an extra amp.
> >
> > Now, for a certain current into the integrator, the integration
capacitor
> > in case (a) will be much smaller. (Larger voltage to pass in the same
time
> > at th esame current.)
> >
> > What is better, in terms of precision / leakage?
> >
> > At first glance, I'd say leakage is mostly leakage _currents_, so
> > it will be the same in both cases.
> > At second glance, I'd say if the leakage currents are not entirely
> > independent with voltage, case (a) will be worse.
> >
> > Is this right? Are there other things to consider?
> >
> > Background: VCO which not only will run from 0.03 Hz to 20kHz,
> > but which will also produce very precise waveforms over that
> > whole range.
> >
> > Any ideas / hints welcome.
> >
> > JH.
> >
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>
>