Re: Accurately measure C of electrolytic capacitors ?

From: gmv (noemail_at_please.123)
Date: 02/08/05 

Date: Tue, 08 Feb 2005 18:15:22 GMT

I think this is the link you mean:
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F011%5F002%5F002%5F000&product%5Fid=276%2D170

The one you gave me would not function.

Yes, I will eventually do this.
I am still debating whether or not to use
what I call equalization in my circuit.

Thanks for your input. 

-- 
Regards;
 gmv
"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com> wrote in message news:110h4qnsbpb3rf2@corp.supernews.com...
>
> "gmv" <noemail@please.123> wrote in message
> news:J7MNd.24453$C24.9065@attbi_s52...
>>
>> "Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com>
> wrote in message news:110cnbn267cd7fe@corp.supernews.com...
>> >
>> > "gmv" <noemail@please.123> wrote in message
>> > news:jJdNd.21541$C24.9629@attbi_s52...
>> >> Interesting,
>> >> I always thought the opamp buffered the output
>> >> so you could hook it to anything between 2K
>> >> and infinity.
>> >> I will keep in mind what you have said.
>> >> I have noticed a terrible ringing effect at Q
>> >> 5 and above.
>> >> Maybe that is what you are talking about.
>> >> In any case I really need to see things between .5Hz
>> >> and 2Hz.  It is only the noise in my local area that
>> >> keeps me from doing this as far as I can tell.
>> >>
>> >> http://home.mchsi.com/~gmvoeth/index.html
>> >>
>> >> will show a bit more of what I am doing.
>> >
>> > Buy the RS printed circuit board that has the same layout as the
>> > breadoard.  Build the circuit on that board, and put it inside of a
>> > metal enclosure, so that most of the noise is kept out of the
> circuit.
>>
>> What is "RS printed circuit board " ?
>
> RS = Radio Shack AKA Radio Scrap, etc.  They sell a PC board that has
> the same layout as the breadboard.  Makes it easy to transfer the
> circuit to a permanent circuit board.
>
>> I have settled on using only a single filter
>> as is now posted to my web site. This will
>> limit one to only seeing P waves but in
>> this noisy environment it is the best I can do.
>> I agree with everything you say except I can not
>> put a preamp outside with the Geophone.
>
> Well, that's probably the reason why you are getting so much noise!
>
>> There is a circuit I have included not on the
>> schematic and it is a 567 tone decoder on the back
>> end to decode WWV calibration marks.
>
>> Thanks for your advice, I can see a lot of
>> common sense to it. But I still do not
>> know how to buy a circuit board that already
>> has my layout on it. I figure I will have
>> to do the layout and etching etc... myself.
>
> I'm not sure you understand.  The hole patterns match those on the
> breadboard.
> Here it is, it's catalog # 276-170 and costs a bit over $3.
> http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fnam
> e=CTLG%5F011%5F002%5F002%5F000&product%5Fid=276%2D170&MSCSProfile=745D84
> CBF04D14A48AA6FF9C89D722C0BA68C1B04FE384678A5285FCD6E056B17AF21627FDABE3
> 16B90B3C038D68EBD6B7F9F3BD1712EAA9951ACB2590A05C6517EFE46941FEFDD1985D4E
> FD6321F5E70B4DE9B6C1D45512DCD9FB3DBCACB9479D26760FAF1D7B193B4FEA078B5E09
> 80BDD61634ABB7D328B012D36915420A2B457BE162481F674B
>
>
>> > All preamplification should be done as close as possible to the
>> > geophone, to get the signal well above the noise _before_ it goes
> any
>> > distance.
>> >
>> > Filtering should be done at the other end, to get rid of noise in
> the
>> > long transmission line between the sensor and the PC.
>> >
>> > One other important point.  The outside can of the electrolytic is
> at
>> > signal level, and is a large capacitance to the outside world.  Just
>> > shielding these from outside noise should help.  You might consider
>> > putting some aluminum foil over the ones at the input, and grounding
> the
>> > foil to common.  Just to see how much it will help to put the whole
>> > thing in an enclosure.
>
> [snip]
>
>

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