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

2012-01-06 Thread Bob Camp
: Thursday, January 05, 2012 5:50 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Thunderbolt? (re simple gpsdo.) capacitors In message CAL8XPmO76XuTETZC=33_v2YWuJGcw8gCvtTDHyae6E4MFb18=g...@mail.gmail.com , Azelio Boriani writes: I have googled extensively

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

2012-01-06 Thread Azelio Boriani
: Re: [time-nuts] Thunderbolt? (re simple gpsdo.) capacitors In message CAL8XPmO76XuTETZC=33_v2YWuJGcw8gCvtTDHyae6E4MFb18=g...@mail.gmail.com , Azelio Boriani writes: I have googled extensively trying to find something about the dual capacitor method of reducing the leakage current... nothing

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

2012-01-05 Thread WarrenS
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

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

2012-01-05 Thread Azelio Boriani
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

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

2012-01-05 Thread lists
Perhaps the dual cap is a differential implementation of the filter/integrator. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.

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

2012-01-05 Thread Azelio Boriani
... don't know but judging from the very simple ASCII schematic I'll say no because the lower capacitor is grounded. There is some sort of feedback I can't figure out, too simple that schematic. On Thu, Jan 5, 2012 at 11:27 PM, li...@lazygranch.com wrote: Perhaps the dual cap is a differential

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

2012-01-05 Thread Poul-Henning Kamp
In message CAL8XPmO76XuTETZC=33_v2YWuJGcw8gCvtTDHyae6E4MFb18=g...@mail.gmail.com , Azelio Boriani writes: 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?

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

2012-01-05 Thread paul swed
Poul Thanks have been kind of following this thread and the diagram did not make a lot of sense. I figured I missed part of the thread. But this clears it up nicely. Regards Paul. WB8TSL On Thu, Jan 5, 2012 at 5:49 PM, Poul-Henning Kamp p...@phk.freebsd.dkwrote: In message

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

2012-01-05 Thread Azelio Boriani
Thanks. Me too: now I got it, sort of bootstrap and now I see that R2 is needed because the real filter is R2*C2 and the leakage is not totally compensated if C1 has to move to a new value - R*C1R2*C2. On Fri, Jan 6, 2012 at 12:00 AM, paul swed paulsw...@gmail.com wrote: Poul Thanks have been

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

2012-01-05 Thread shalimr9
and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Thunderbolt? (re simple gpsdo.) capacitors In message CAL8XPmO76XuTETZC=33_v2YWuJGcw8gCvtTDHyae6E4MFb18=g...@mail.gmail.com , Azelio Boriani writes: I have googled extensively trying to find something about the dual

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

2012-01-03 Thread Bob Camp
Hi Using electrolytic caps in timing applications is a bit exciting. Their leakage current changes each time you change the voltage on them. It's enough of a change to significantly impact long time constants. In some cases the capacitance changes with voltage as well. Temperature stability of

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

2012-01-03 Thread Chris Albertson
On Tue, Jan 3, 2012 at 9:14 AM, Bob Camp li...@rtty.us wrote: Hi Using electrolytic caps in timing applications is a bit exciting. Their leakage current changes each time you change the voltage on them. It's enough of a change to significantly impact long time constants. In some cases the

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

2012-01-03 Thread Bob Camp
Of Chris Albertson Sent: Tuesday, January 03, 2012 12:35 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Thunderbolt? (re simple gpsdo.) capacitors On Tue, Jan 3, 2012 at 9:14 AM, Bob Camp li...@rtty.us wrote: Hi Using electrolytic caps in timing applications

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

2012-01-03 Thread WarrenS
no effect on it's charge voltage. I guess the charge is not Fixed, so not the same thing as changing the value by paralleling the cap. ws ** [time-nuts] Thunderbolt? (re simple gpsdo.) capacitors Bob Camp lists at rtty.us Hi No argument there, but this thread has wandered a bit

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

2012-01-03 Thread Poul-Henning Kamp
In message 80B26DC756AA45DD84E4EB9E14B58998@Warcon28Gz, WarrenS writes: The leakage current noise I measured was way below insignificant when things are properly scaled. Really stupid question: Couldn't the double condensor from voltage references trick be used to eliminate the leakage