[time-nuts] Thunderbolt? (re simple gpsdo.) >> capacitors

[Azelio Boriani]

I have googled extensively trying to find something about the dual
capacitor method of reducing the leakage current... nothing found. Please,
can you indicate anything for me to learn more?
Thank you

On Thu, Jan 5, 2012 at 9:18 PM, WarrenS <warrensjmail-one at yahoo.com> wrote:

>
> Yes almost as long as you include ONE more Resistor, R2 added below.
> The dual cap thing does not get rid of leakage entirely, but close enough
> in most cases.
> That configuration is most useful for slow open loop filters when you want
> low leakage errors.
>
> It may be a bit of an overkill for a closed loop filters when a 10 %
> leakage would be tolerable.
> I tested a 10,000 sec TC filter using a 10 meg and 1000 uF, and got under
> 1% leakage error open loop.
>
> ws
>
>
> ***************
>
> [time-nuts] Thunderbolt? (re simple gpsdo.) >> capacitors
> Poul-Henning Kamp phk at phk.freebsd.dk
>
>
>  The leakage current noise I measured was way below insignificant when
>>> things are properly scaled.
>>>
>>
>  Couldn't the "double condensor" from voltage references trick be used to
>> eliminate the leakage entirely ?
>>
>
>
> [Some op-amp]  >-+-----R2-----+-->
>                              |                  |
>                              |               -----
>                              |               -----
>                              |     ____     |
>                             +---|____|---+
>
>                                                |
>                                             -----
>                                             -----
>                                                |
>                                            GND
> --
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
>
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