Message-ID:

6 May, 2024: The networking issue during the past two days has been identified and fixed.

tech / sci.electronics.design / Re: Moscaps? Any ideas?

Moscaps? Any ideas?

<16Z1L.624898$iiS8.110148@fx17.iad>

https://www.novabbs.com/tech/article-flat.php?id=107875&group=sci.electronics.design#107875

copy link Newsgroups: sci.electronics.design

Path: i2pn2.org!i2pn.org!weretis.net!feeder6.news.weretis.net!usenet.blueworldhosting.com!feed1.usenet.blueworldhosting.com!peer02.iad!feed-me.highwinds-media.com!news.highwinds-media.com!fx17.iad.POSTED!not-for-mail
Newsgroups: sci.electronics.design
X-Mozilla-News-Host: news://news.easynews.com:119
From: Chipbee4...@yahoo.com (JC)
Subject: Moscaps? Any ideas?
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101
Firefox/68.0 SeaMonkey/2.53.14
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Lines: 11
Message-ID: <16Z1L.624898$iiS8.110148@fx17.iad>
X-Complaints-To: abuse@easynews.com
Organization: Easynews - www.easynews.com
X-Complaints-Info: Please be sure to forward a copy of ALL headers otherwise we will be unable to process your complaint properly.
Date: Thu, 13 Oct 2022 14:50:38 -0400
X-Received-Bytes: 1200

by: JC - Thu, 13 Oct 2022 18:50 UTC

Hi, Anyone care to explain what the function is of the 2 FETS Q1 and Q2
in this Fluke calibrator and what might be the required parameters for a
replacement?

https://www.flickr.com/photos/40466580@N07/

It fails diagnostics with leakage caused by one of these. At the moment
I have them replaced with J210 FETS which I had to hand but I think
there's maybe more to it than that. I cant find any data on them, they
are marked IFC 07703
TIA JC

Re: Moscaps? Any ideas?

<b0bb6d6f-fa22-bcc2-79aa-787abb6d6316@electrooptical.net>

copy mid

https://www.novabbs.com/tech/article-flat.php?id=107879&group=sci.electronics.design#107879

copy link Newsgroups: sci.electronics.design

Path: i2pn2.org!i2pn.org!eternal-september.org!reader01.eternal-september.org!.POSTED!not-for-mail
From: pcdhSpam...@electrooptical.net (Phil Hobbs)
Newsgroups: sci.electronics.design
Subject: Re: Moscaps? Any ideas?
Date: Thu, 13 Oct 2022 16:40:18 -0400
Organization: A noiseless patient Spider
Lines: 29
Message-ID: <b0bb6d6f-fa22-bcc2-79aa-787abb6d6316@electrooptical.net>
References: <16Z1L.624898$iiS8.110148@fx17.iad>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Info: reader01.eternal-september.org; posting-host="cb4d6b302ae5367774449791454fc2f1";
logging-data="1975445"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19sTqrLWzbGYSmgXCZbEMWk"
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
Thunderbird/78.0
Cancel-Lock: sha1:5BC0ztLF4zuQYtmdFOYN7vYk0Ts=
In-Reply-To: <16Z1L.624898$iiS8.110148@fx17.iad>

by: Phil Hobbs - Thu, 13 Oct 2022 20:40 UTC

JC wrote:
> Hi, Anyone care to explain what the function is of the 2 FETS Q1 and Q2
> in this Fluke calibrator and what might be the required parameters for a
> replacement?
>
> https://www.flickr.com/photos/40466580@N07/
>
> It fails diagnostics with leakage caused by one of these. At the moment
> I have them replaced with J210 FETS which I had to hand but I think
> there's maybe more to it than that. I cant find any data on them, they
> are marked IFC 07703
> TIA JC

Protection diodes.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

Re: Moscaps? Any ideas?

<jbugkhhilllgq9bp08jdfan69a3f4li48j@4ax.com>

copy mid

https://www.novabbs.com/tech/article-flat.php?id=107880&group=sci.electronics.design#107880

copy link Newsgroups: sci.electronics.design

Path: i2pn2.org!i2pn.org!weretis.net!feeder6.news.weretis.net!news.misty.com!border-2.nntp.ord.giganews.com!nntp.giganews.com!Xl.tags.giganews.com!local-1.nntp.ord.giganews.com!nntp.supernews.com!news.supernews.com.POSTED!not-for-mail
NNTP-Posting-Date: Thu, 13 Oct 2022 20:52:19 +0000
From: jlar...@highland_atwork_technology.com (John Larkin)
Newsgroups: sci.electronics.design
Subject: Re: Moscaps? Any ideas?
Date: Thu, 13 Oct 2022 13:52:19 -0700
Organization: Highland Tech
Reply-To: xx@yy.com
Message-ID: <jbugkhhilllgq9bp08jdfan69a3f4li48j@4ax.com>
References: <16Z1L.624898$iiS8.110148@fx17.iad> <b0bb6d6f-fa22-bcc2-79aa-787abb6d6316@electrooptical.net>
X-Newsreader: Forte Agent 3.1/32.783
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Lines: 29
X-Trace: sv3-k8QOuVakibuz8Bn8nH8cefrQYrhWO9zQHjfgk7N1rHDFb8hyoY7hlJc06oSgA0aznjFW107GeZe93Gk!C4TS3FU0yKh1qLl5AZQWPGjHcd/9lF45W3VrfoNXhZOrou0QBopBzH23391pwJP8ILXxCcHixe/2!fmdzDg==
X-Complaints-To: www.supernews.com/docs/abuse.html
X-DMCA-Complaints-To: www.supernews.com/docs/dmca.html
X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers
X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly
X-Postfilter: 1.3.40

by: John Larkin - Thu, 13 Oct 2022 20:52 UTC

On Thu, 13 Oct 2022 16:40:18 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>JC wrote:
>> Hi, Anyone care to explain what the function is of the 2 FETS Q1 and Q2
>> in this Fluke calibrator and what might be the required parameters for a
>> replacement?
>>
>> https://www.flickr.com/photos/40466580@N07/
>>
>> It fails diagnostics with leakage caused by one of these. At the moment
>> I have them replaced with J210 FETS which I had to hand but I think
>> there's maybe more to it than that. I cant find any data on them, they
>> are marked IFC 07703
>> TIA JC
>
>Protection diodes.
>
>Cheers
>
>Phil Hobbs

Yes, jfets used as diodes. Terrible idea.

The c-b junction of a small transistor would be better all-around.
BFT25 has fA leakage... if you can get them. I could spare a few.

There's probably a common TO92 transistor with sub-pA leakage.

Re: Moscaps? Any ideas?

<82e2b0ef-6fe4-4d31-9fee-853854ad8064n@googlegroups.com>

copy mid

https://www.novabbs.com/tech/article-flat.php?id=107882&group=sci.electronics.design#107882

copy link Newsgroups: sci.electronics.design

X-Received: by 2002:ac8:5a95:0:b0:39a:86a3:5032 with SMTP id c21-20020ac85a95000000b0039a86a35032mr1775385qtc.96.1665696571214;
Thu, 13 Oct 2022 14:29:31 -0700 (PDT)
X-Received: by 2002:a05:620a:3199:b0:6e7:7ac8:5b4 with SMTP id
bi25-20020a05620a319900b006e77ac805b4mr1623238qkb.192.1665696571006; Thu, 13
Oct 2022 14:29:31 -0700 (PDT)
Path: i2pn2.org!i2pn.org!weretis.net!feeder6.news.weretis.net!usenet.blueworldhosting.com!feed1.usenet.blueworldhosting.com!peer02.iad!feed-me.highwinds-media.com!news.highwinds-media.com!news-out.google.com!nntp.google.com!postnews.google.com!google-groups.googlegroups.com!not-for-mail
Newsgroups: sci.electronics.design
Date: Thu, 13 Oct 2022 14:29:30 -0700 (PDT)
In-Reply-To: <jbugkhhilllgq9bp08jdfan69a3f4li48j@4ax.com>
Injection-Info: google-groups.googlegroups.com; posting-host=94.145.249.187; posting-account=mW5JKwkAAAAMyuWOVeLp8yffyAkVx0g7
NNTP-Posting-Host: 94.145.249.187
References: <16Z1L.624898$iiS8.110148@fx17.iad> <b0bb6d6f-fa22-bcc2-79aa-787abb6d6316@electrooptical.net>
<jbugkhhilllgq9bp08jdfan69a3f4li48j@4ax.com>
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <82e2b0ef-6fe4-4d31-9fee-853854ad8064n@googlegroups.com>
Subject: Re: Moscaps? Any ideas?
From: langw...@fonz.dk (Lasse Langwadt Christensen)
Injection-Date: Thu, 13 Oct 2022 21:29:31 +0000
Content-Type: text/plain; charset="UTF-8"
X-Received-Bytes: 2272

by: Lasse Langwadt Chris - Thu, 13 Oct 2022 21:29 UTC

torsdag den 13. oktober 2022 kl. 22.52.31 UTC+2 skrev John Larkin:
> On Thu, 13 Oct 2022 16:40:18 -0400, Phil Hobbs
> <pcdhSpamM...@electrooptical.net> wrote:
>
> >JC wrote:
> >> Hi, Anyone care to explain what the function is of the 2 FETS Q1 and Q2
> >> in this Fluke calibrator and what might be the required parameters for a
> >> replacement?
> >>
> >> https://www.flickr.com/photos/40466580@N07/
> >>
> >> It fails diagnostics with leakage caused by one of these. At the moment
> >> I have them replaced with J210 FETS which I had to hand but I think
> >> there's maybe more to it than that. I cant find any data on them, they
> >> are marked IFC 07703
> >> TIA JC
> >
> >Protection diodes.
> >
> >Cheers
> >
> >Phil Hobbs
> Yes, jfets used as diodes. Terrible idea.
>
> The c-b junction of a small transistor would be better all-around.
> BFT25 has fA leakage... if you can get them. I could spare a few.
>
> There's probably a common TO92 transistor with sub-pA leakage.

https://youtu.be/BGcKjy_UNQ4

Re: Moscaps? Any ideas?

<421ac071-8609-7b34-a408-05120640dbfd@electrooptical.net>

copy mid

https://www.novabbs.com/tech/article-flat.php?id=107883&group=sci.electronics.design#107883

copy link Newsgroups: sci.electronics.design

Path: i2pn2.org!i2pn.org!eternal-september.org!reader01.eternal-september.org!.POSTED!not-for-mail
From: pcdhSpam...@electrooptical.net (Phil Hobbs)
Newsgroups: sci.electronics.design
Subject: Re: Moscaps? Any ideas?
Date: Thu, 13 Oct 2022 17:39:44 -0400
Organization: A noiseless patient Spider
Lines: 34
Message-ID: <421ac071-8609-7b34-a408-05120640dbfd@electrooptical.net>
References: <16Z1L.624898$iiS8.110148@fx17.iad>
<b0bb6d6f-fa22-bcc2-79aa-787abb6d6316@electrooptical.net>
<jbugkhhilllgq9bp08jdfan69a3f4li48j@4ax.com>
<82e2b0ef-6fe4-4d31-9fee-853854ad8064n@googlegroups.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Info: reader01.eternal-september.org; posting-host="cb4d6b302ae5367774449791454fc2f1";
logging-data="1984180"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19gywrt+On/lnjky9eKmnrr"
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
Thunderbird/78.0
Cancel-Lock: sha1:6Hs4aZrOXUlGSe8T/orp1WaJJIU=
In-Reply-To: <82e2b0ef-6fe4-4d31-9fee-853854ad8064n@googlegroups.com>

by: Phil Hobbs - Thu, 13 Oct 2022 21:39 UTC

Lasse Langwadt Christensen wrote:
> torsdag den 13. oktober 2022 kl. 22.52.31 UTC+2 skrev John Larkin:
>> On Thu, 13 Oct 2022 16:40:18 -0400, Phil Hobbs
>> <pcdhSpamM...@electrooptical.net> wrote:
>>
>>> JC wrote:
>>>> Hi, Anyone care to explain what the function is of the 2 FETS Q1 and Q2
>>>> in this Fluke calibrator and what might be the required parameters for a
>>>> replacement?
>>>>
>>>> https://www.flickr.com/photos/40466580@N07/
>>>>
>>>> It fails diagnostics with leakage caused by one of these. At the moment
>>>> I have them replaced with J210 FETS which I had to hand but I think
>>>> there's maybe more to it than that. I cant find any data on them, they
>>>> are marked IFC 07703
>>>> TIA JC
>>>
>>> Protection diodes.
>>>
>>> Cheers
>>>
>>> Phil Hobbs
>> Yes, jfets used as diodes. Terrible idea.
>>
>> The c-b junction of a small transistor would be better all-around.
>> BFT25 has fA leakage... if you can get them. I could spare a few.
>>
>> There's probably a common TO92 transistor with sub-pA leakage.
>
>
> https://youtu.be/BGcKjy_UNQ4
>
Oh no! It's Squeaky Dave!

Re: Moscaps? Any ideas?

<8256d414-a7a8-423b-8740-90484e98692fn@googlegroups.com>

copy mid

https://www.novabbs.com/tech/article-flat.php?id=107886&group=sci.electronics.design#107886

copy link Newsgroups: sci.electronics.design

X-Received: by 2002:ac8:5a95:0:b0:39a:86a3:5032 with SMTP id c21-20020ac85a95000000b0039a86a35032mr1861672qtc.96.1665698384407;
Thu, 13 Oct 2022 14:59:44 -0700 (PDT)
X-Received: by 2002:a0c:9a0d:0:b0:4b1:982e:96d4 with SMTP id
p13-20020a0c9a0d000000b004b1982e96d4mr1829561qvd.114.1665698384206; Thu, 13
Oct 2022 14:59:44 -0700 (PDT)
Path: i2pn2.org!i2pn.org!news.niel.me!glou.org!news.glou.org!usenet-fr.net!proxad.net!feeder1-2.proxad.net!209.85.160.216.MISMATCH!news-out.google.com!nntp.google.com!postnews.google.com!google-groups.googlegroups.com!not-for-mail
Newsgroups: sci.electronics.design
Date: Thu, 13 Oct 2022 14:59:43 -0700 (PDT)
In-Reply-To: <421ac071-8609-7b34-a408-05120640dbfd@electrooptical.net>
Injection-Info: google-groups.googlegroups.com; posting-host=94.145.249.187; posting-account=mW5JKwkAAAAMyuWOVeLp8yffyAkVx0g7
NNTP-Posting-Host: 94.145.249.187
References: <16Z1L.624898$iiS8.110148@fx17.iad> <b0bb6d6f-fa22-bcc2-79aa-787abb6d6316@electrooptical.net>
<jbugkhhilllgq9bp08jdfan69a3f4li48j@4ax.com> <82e2b0ef-6fe4-4d31-9fee-853854ad8064n@googlegroups.com>
<421ac071-8609-7b34-a408-05120640dbfd@electrooptical.net>
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <8256d414-a7a8-423b-8740-90484e98692fn@googlegroups.com>
Subject: Re: Moscaps? Any ideas?
From: langw...@fonz.dk (Lasse Langwadt Christensen)
Injection-Date: Thu, 13 Oct 2022 21:59:44 +0000
Content-Type: text/plain; charset="UTF-8"

by: Lasse Langwadt Chris - Thu, 13 Oct 2022 21:59 UTC

torsdag den 13. oktober 2022 kl. 23.39.56 UTC+2 skrev Phil Hobbs:
> Lasse Langwadt Christensen wrote:
> > torsdag den 13. oktober 2022 kl. 22.52.31 UTC+2 skrev John Larkin:
> >> On Thu, 13 Oct 2022 16:40:18 -0400, Phil Hobbs
> >> <pcdhSpamM...@electrooptical.net> wrote:
> >>
> >>> JC wrote:
> >>>> Hi, Anyone care to explain what the function is of the 2 FETS Q1 and Q2
> >>>> in this Fluke calibrator and what might be the required parameters for a
> >>>> replacement?
> >>>>
> >>>> https://www.flickr.com/photos/40466580@N07/
> >>>>
> >>>> It fails diagnostics with leakage caused by one of these. At the moment
> >>>> I have them replaced with J210 FETS which I had to hand but I think
> >>>> there's maybe more to it than that. I cant find any data on them, they
> >>>> are marked IFC 07703
> >>>> TIA JC
> >>>
> >>> Protection diodes.
> >>>
> >>> Cheers
> >>>
> >>> Phil Hobbs
> >> Yes, jfets used as diodes. Terrible idea.
> >>
> >> The c-b junction of a small transistor would be better all-around.
> >> BFT25 has fA leakage... if you can get them. I could spare a few.
> >>
> >> There's probably a common TO92 transistor with sub-pA leakage.
> >
> >
> > https://youtu.be/BGcKjy_UNQ4
> >
> Oh no! It's Squeaky Dave!

he doesn't drink, so his voice never gets lubricated ;)

Re: Moscaps? Any ideas?

<80260e43-9298-5a68-86a6-dc6e7e00d816@electrooptical.net>

copy mid

https://www.novabbs.com/tech/article-flat.php?id=107887&group=sci.electronics.design#107887

copy link Newsgroups: sci.electronics.design

Path: i2pn2.org!i2pn.org!weretis.net!feeder6.news.weretis.net!news.misty.com!border-2.nntp.ord.giganews.com!nntp.giganews.com!Xl.tags.giganews.com!local-1.nntp.ord.giganews.com!nntp.supernews.com!news.supernews.com.POSTED!not-for-mail
NNTP-Posting-Date: Thu, 13 Oct 2022 22:07:08 +0000
Subject: Re: Moscaps? Any ideas?
Newsgroups: sci.electronics.design
References: <16Z1L.624898$iiS8.110148@fx17.iad>
<b0bb6d6f-fa22-bcc2-79aa-787abb6d6316@electrooptical.net>
<jbugkhhilllgq9bp08jdfan69a3f4li48j@4ax.com>
<82e2b0ef-6fe4-4d31-9fee-853854ad8064n@googlegroups.com>
<421ac071-8609-7b34-a408-05120640dbfd@electrooptical.net>
<8256d414-a7a8-423b-8740-90484e98692fn@googlegroups.com>
From: pcdhSpam...@electrooptical.net (Phil Hobbs)
Message-ID: <80260e43-9298-5a68-86a6-dc6e7e00d816@electrooptical.net>
Date: Thu, 13 Oct 2022 18:07:07 -0400
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
Thunderbird/78.0
MIME-Version: 1.0
In-Reply-To: <8256d414-a7a8-423b-8740-90484e98692fn@googlegroups.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Lines: 40
X-Trace: sv3-gUhIbn4G4VQalq41pT1slWTYyZ7XiSCImvPIY0GbJsfKQXhU2eKJX7y6dwAqt/7Ew+vQQUQnZR5OsCD!2DKD6YT14lKH3HvapiWyw4PRy9jM4WrKyDH1AFWEsLuQSpW40Yx1Fa+RIUnxg9yEjDpTsTFBNb2X!kS1G2BkbbQkND7PBfAeLpg7l
X-Complaints-To: www.supernews.com/docs/abuse.html
X-DMCA-Complaints-To: www.supernews.com/docs/dmca.html
X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers
X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly
X-Postfilter: 1.3.40

by: Phil Hobbs - Thu, 13 Oct 2022 22:07 UTC

Lasse Langwadt Christensen wrote:
> torsdag den 13. oktober 2022 kl. 23.39.56 UTC+2 skrev Phil Hobbs:
>> Lasse Langwadt Christensen wrote:
>>> torsdag den 13. oktober 2022 kl. 22.52.31 UTC+2 skrev John Larkin:
>>>> On Thu, 13 Oct 2022 16:40:18 -0400, Phil Hobbs
>>>> <pcdhSpamM...@electrooptical.net> wrote:
>>>>
>>>>> JC wrote:
>>>>>> Hi, Anyone care to explain what the function is of the 2 FETS Q1 and Q2
>>>>>> in this Fluke calibrator and what might be the required parameters for a
>>>>>> replacement?
>>>>>>
>>>>>> https://www.flickr.com/photos/40466580@N07/
>>>>>>
>>>>>> It fails diagnostics with leakage caused by one of these. At the moment
>>>>>> I have them replaced with J210 FETS which I had to hand but I think
>>>>>> there's maybe more to it than that. I cant find any data on them, they
>>>>>> are marked IFC 07703
>>>>>> TIA JC
>>>>>
>>>>> Protection diodes.
>>>>>
>>>>> Cheers
>>>>>
>>>>> Phil Hobbs
>>>> Yes, jfets used as diodes. Terrible idea.
>>>>
>>>> The c-b junction of a small transistor would be better all-around.
>>>> BFT25 has fA leakage... if you can get them. I could spare a few.
>>>>
>>>> There's probably a common TO92 transistor with sub-pA leakage.
>>>
>>>
>>> https://youtu.be/BGcKjy_UNQ4
>>>
>> Oh no! It's Squeaky Dave!
>
> he doesn't drink, so his voice never gets lubricated ;)
>
A big of brake cleaner might help. ;)

Re: Moscaps? Any ideas?

<_Vc2L.547243$6Il8.456716@fx14.iad>

copy mid

https://www.novabbs.com/tech/article-flat.php?id=107927&group=sci.electronics.design#107927

copy link Newsgroups: sci.electronics.design

Path: i2pn2.org!i2pn.org!usenet.blueworldhosting.com!feed1.usenet.blueworldhosting.com!peer01.iad!feed-me.highwinds-media.com!news.highwinds-media.com!fx14.iad.POSTED!not-for-mail
Subject: Re: Moscaps? Any ideas?
Newsgroups: sci.electronics.design
References: <16Z1L.624898$iiS8.110148@fx17.iad>
<b0bb6d6f-fa22-bcc2-79aa-787abb6d6316@electrooptical.net>
<jbugkhhilllgq9bp08jdfan69a3f4li48j@4ax.com>
From: Chipbee4...@yahoo.com (JC)
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101
Firefox/68.0 SeaMonkey/2.53.14
MIME-Version: 1.0
In-Reply-To: <jbugkhhilllgq9bp08jdfan69a3f4li48j@4ax.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Lines: 32
Message-ID: <_Vc2L.547243$6Il8.456716@fx14.iad>
X-Complaints-To: abuse@easynews.com
Organization: Easynews - www.easynews.com
X-Complaints-Info: Please be sure to forward a copy of ALL headers otherwise we will be unable to process your complaint properly.
Date: Fri, 14 Oct 2022 08:50:05 -0400
X-Received-Bytes: 1900

by: JC - Fri, 14 Oct 2022 12:50 UTC

John Larkin wrote:
> On Thu, 13 Oct 2022 16:40:18 -0400, Phil Hobbs
> <pcdhSpamMeSenseless@electrooptical.net> wrote:
>
>> JC wrote:
>>> Hi, Anyone care to explain what the function is of the 2 FETS Q1 and Q2
>>> in this Fluke calibrator and what might be the required parameters for a
>>> replacement?
>>>
>>> https://www.flickr.com/photos/40466580@N07/
>>>
>>> It fails diagnostics with leakage caused by one of these. At the moment
>>> I have them replaced with J210 FETS which I had to hand but I think
>>> there's maybe more to it than that. I cant find any data on them, they
>>> are marked IFC 07703
>>> TIA JC
>>
>> Protection diodes.
>>
>> Cheers
>>
>> Phil Hobbs
>
> Yes, jfets used as diodes. Terrible idea.
>
> The c-b junction of a small transistor would be better all-around.
> BFT25 has fA leakage... if you can get them. I could spare a few.
>
> There's probably a common TO92 transistor with sub-pA leakage.
>
Thanks for the replies.
JC

Re: Moscaps? Any ideas?

<tibruc$258jn$1@dont-email.me>

copy mid

https://www.novabbs.com/tech/article-flat.php?id=107936&group=sci.electronics.design#107936

copy link Newsgroups: sci.electronics.design

Path: i2pn2.org!i2pn.org!eternal-september.org!reader01.eternal-september.org!.POSTED!not-for-mail
From: tauno.vo...@notused.fi.invalid (Tauno Voipio)
Newsgroups: sci.electronics.design
Subject: Re: Moscaps? Any ideas?
Date: Fri, 14 Oct 2022 17:32:42 +0300
Organization: A noiseless patient Spider
Lines: 45
Message-ID: <tibruc$258jn$1@dont-email.me>
References: <16Z1L.624898$iiS8.110148@fx17.iad>
<b0bb6d6f-fa22-bcc2-79aa-787abb6d6316@electrooptical.net>
<jbugkhhilllgq9bp08jdfan69a3f4li48j@4ax.com>
<_Vc2L.547243$6Il8.456716@fx14.iad>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Fri, 14 Oct 2022 14:32:45 -0000 (UTC)
Injection-Info: reader01.eternal-september.org; posting-host="122c5ea73b3da24dcd6c4604b4c182fd";
logging-data="2269815"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19f+uFF5KQRhZMn67sTOXS2/bSHQsO0FpI="
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0)
Gecko/20100101 Thunderbird/102.3.3
Cancel-Lock: sha1:sS3ifuWOALvAzrBI5ESTtbsZIhk=
In-Reply-To: <_Vc2L.547243$6Il8.456716@fx14.iad>

by: Tauno Voipio - Fri, 14 Oct 2022 14:32 UTC

There are special low-leakage diodes, just Google for
'picoampere diode'.

The best-known is called PAD-1, from several manufacturers.

-TV

On 14.10.22 15.50, JC wrote:
> John Larkin wrote:
>> On Thu, 13 Oct 2022 16:40:18 -0400, Phil Hobbs
>> <pcdhSpamMeSenseless@electrooptical.net> wrote:
>>
>>> JC wrote:
>>>> Hi, Anyone care to explain what the function is of the 2 FETS Q1 and Q2
>>>> in this Fluke calibrator and what might be the required parameters
>>>> for a
>>>> replacement?
>>>>
>>>> https://www.flickr.com/photos/40466580@N07/
>>>>
>>>> It fails diagnostics with leakage caused by one of these. At the moment
>>>> I have them replaced with J210 FETS which I had to hand but I think
>>>> there's maybe more to it than that. I cant find any data on them, they
>>>> are marked IFC 07703
>>>> TIA JC
>>>
>>> Protection diodes.
>>>
>>> Cheers
>>>
>>> Phil Hobbs
>>
>> Yes, jfets used as diodes. Terrible idea.
>>
>> The c-b junction of a small transistor would be better all-around.
>> BFT25 has fA leakage... if you can get them. I could spare a few.
>>
>> There's probably a common TO92 transistor with sub-pA leakage.
>>
> Thanks for the replies.
> JC

Re: Moscaps? Any ideas?

<p91jkhpcdsp4680aoqvfua8dr8825348r3@4ax.com>

copy mid

https://www.novabbs.com/tech/article-flat.php?id=107946&group=sci.electronics.design#107946

copy link Newsgroups: sci.electronics.design

Path: i2pn2.org!i2pn.org!usenet.blueworldhosting.com!feed1.usenet.blueworldhosting.com!peer01.iad!feed-me.highwinds-media.com!news.highwinds-media.com!novia.net!not-for-mail
From: boB...@K7IQ.com (boB)
Newsgroups: sci.electronics.design
Subject: Re: Moscaps? Any ideas?
Date: Fri, 14 Oct 2022 08:51:21 -0700
Message-ID: <p91jkhpcdsp4680aoqvfua8dr8825348r3@4ax.com>
References: <16Z1L.624898$iiS8.110148@fx17.iad> <b0bb6d6f-fa22-bcc2-79aa-787abb6d6316@electrooptical.net> <jbugkhhilllgq9bp08jdfan69a3f4li48j@4ax.com> <_Vc2L.547243$6Il8.456716@fx14.iad>
User-Agent: ForteAgent/8.00.32.1272
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Lines: 44
NNTP-Posting-Host: 6a6f3046.newscene.com
X-Trace: DXC=59>64NK8heOUmmMiAXHZUD;^NkA6HIcBBV[l?>g^C2\H^4M`nEinNJF;K?l]heic\G4cT@F8RL;6FI;gnMM\2\8L45dRNDi2[n@
X-Complaints-To: abuse@newscene.com
X-Received-Bytes: 2073

by: boB - Fri, 14 Oct 2022 15:51 UTC

On Fri, 14 Oct 2022 08:50:05 -0400, JC <Chipbee40_SpamNo@yahoo.com>
wrote:

>John Larkin wrote:
>> On Thu, 13 Oct 2022 16:40:18 -0400, Phil Hobbs
>> <pcdhSpamMeSenseless@electrooptical.net> wrote:
>>
>>> JC wrote:
>>>> Hi, Anyone care to explain what the function is of the 2 FETS Q1 and Q2
>>>> in this Fluke calibrator and what might be the required parameters for a
>>>> replacement?
>>>>
>>>> https://www.flickr.com/photos/40466580@N07/
>>>>
>>>> It fails diagnostics with leakage caused by one of these. At the moment
>>>> I have them replaced with J210 FETS which I had to hand but I think
>>>> there's maybe more to it than that. I cant find any data on them, they
>>>> are marked IFC 07703
>>>> TIA JC
>>>
>>> Protection diodes.
>>>
>>> Cheers
>>>
>>> Phil Hobbs
>>
>> Yes, jfets used as diodes. Terrible idea.
>>
>> The c-b junction of a small transistor would be better all-around.
>> BFT25 has fA leakage... if you can get them. I could spare a few.
>>
>> There's probably a common TO92 transistor with sub-pA leakage.
>>
>Thanks for the replies.
>JC

I would think that if this was a Fluke designed circuit, that it
wouldn't be something that wouldn't work.

The people I know that work in the Fluke calibration engineering
department are pretty smart.

boB

Re: Moscaps? Any ideas?

<3b4jkh1a3cb1mh8m2303stq5ko9ck85vft@4ax.com>

copy mid

https://www.novabbs.com/tech/article-flat.php?id=107952&group=sci.electronics.design#107952

copy link Newsgroups: sci.electronics.design

Path: i2pn2.org!i2pn.org!usenet.blueworldhosting.com!feed1.usenet.blueworldhosting.com!peer01.iad!feed-me.highwinds-media.com!news.highwinds-media.com!feeder.usenetexpress.com!tr1.iad1.usenetexpress.com!69.80.99.22.MISMATCH!Xl.tags.giganews.com!local-2.nntp.ord.giganews.com!nntp.supernews.com!news.supernews.com.POSTED!not-for-mail
NNTP-Posting-Date: Fri, 14 Oct 2022 16:44:07 +0000
From: jlar...@highlandSNIPMEtechnology.com (John Larkin)
Newsgroups: sci.electronics.design
Subject: Re: Moscaps? Any ideas?
Date: Fri, 14 Oct 2022 09:44:09 -0700
Organization: Highland Tech
Reply-To: xx@yy.com
Message-ID: <3b4jkh1a3cb1mh8m2303stq5ko9ck85vft@4ax.com>
References: <16Z1L.624898$iiS8.110148@fx17.iad> <b0bb6d6f-fa22-bcc2-79aa-787abb6d6316@electrooptical.net> <jbugkhhilllgq9bp08jdfan69a3f4li48j@4ax.com> <_Vc2L.547243$6Il8.456716@fx14.iad> <tibruc$258jn$1@dont-email.me>
X-Newsreader: Forte Agent 3.1/32.783
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Lines: 12
X-Trace: sv3-dSsrkkvysv3WvyjVMA5tzIrruGWTUYf77M6plNA5EU/T/h4SaR3Mfqu5gBwQDRH9SEsUohxg6JHX7a7!a78sDI5KQuqHQMnySWN8M0KhkcxkooSFKiH+YUEIRgmFoxMhLc9PFJhzLZ1Ku5Eodyx2fyiP+u7b!rNASqA==
X-Complaints-To: www.supernews.com/docs/abuse.html
X-DMCA-Complaints-To: www.supernews.com/docs/dmca.html
X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers
X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly
X-Postfilter: 1.3.40
X-Received-Bytes: 1777

by: John Larkin - Fri, 14 Oct 2022 16:44 UTC

On Fri, 14 Oct 2022 17:32:42 +0300, Tauno Voipio
<tauno.voipio@notused.fi.invalid> wrote:

>There are special low-leakage diodes, just Google for
>'picoampere diode'.
>
>The best-known is called PAD-1, from several manufacturers.

The PADS are actually jfets. They are expensive, have crazy high
capacitance and series resistance, and leakage is huge compared to a
decent transistor c-b junction.

Re: Moscaps? Any ideas?

<98057272-bf4b-4e23-800e-8d80bd6de183n@googlegroups.com>

copy mid

https://www.novabbs.com/tech/article-flat.php?id=107963&group=sci.electronics.design#107963

copy link Newsgroups: sci.electronics.design

X-Received: by 2002:a05:6214:623:b0:4b4:156a:cd98 with SMTP id a3-20020a056214062300b004b4156acd98mr5373798qvx.102.1665773880622;
Fri, 14 Oct 2022 11:58:00 -0700 (PDT)
X-Received: by 2002:a05:6214:19c5:b0:4b1:863b:805c with SMTP id
j5-20020a05621419c500b004b1863b805cmr5481970qvc.20.1665773880416; Fri, 14 Oct
2022 11:58:00 -0700 (PDT)
Path: i2pn2.org!i2pn.org!usenet.blueworldhosting.com!feed1.usenet.blueworldhosting.com!peer03.iad!feed-me.highwinds-media.com!news.highwinds-media.com!news-out.google.com!nntp.google.com!postnews.google.com!google-groups.googlegroups.com!not-for-mail
Newsgroups: sci.electronics.design
Date: Fri, 14 Oct 2022 11:58:00 -0700 (PDT)
In-Reply-To: <3b4jkh1a3cb1mh8m2303stq5ko9ck85vft@4ax.com>
Injection-Info: google-groups.googlegroups.com; posting-host=74.101.19.38; posting-account=rEo47AoAAAAz23oFFYoL4aHQauGkT8Lw
NNTP-Posting-Host: 74.101.19.38
References: <16Z1L.624898$iiS8.110148@fx17.iad> <b0bb6d6f-fa22-bcc2-79aa-787abb6d6316@electrooptical.net>
<jbugkhhilllgq9bp08jdfan69a3f4li48j@4ax.com> <_Vc2L.547243$6Il8.456716@fx14.iad>
<tibruc$258jn$1@dont-email.me> <3b4jkh1a3cb1mh8m2303stq5ko9ck85vft@4ax.com>
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <98057272-bf4b-4e23-800e-8d80bd6de183n@googlegroups.com>
Subject: Re: Moscaps? Any ideas?
From: richsuli...@gmail.com (Rich S)
Injection-Date: Fri, 14 Oct 2022 18:58:00 +0000
Content-Type: text/plain; charset="UTF-8"
X-Received-Bytes: 2005

by: Rich S - Fri, 14 Oct 2022 18:58 UTC

On Friday, October 14, 2022 at 4:44:20 PM UTC, John Larkin wrote:
> On Fri, 14 Oct 2022 17:32:42 +0300, Tauno Voipio
> <tauno....@notused.fi.invalid> wrote:
>
> >There are special low-leakage diodes, just Google for
> >'picoampere diode'.
> >
> >The best-known is called PAD-1, from several manufacturers.
> The PADS are actually jfets. They are expensive, have crazy high
> capacitance and series resistance, and leakage is huge compared to a
> decent transistor c-b junction.

https://www.interfet.com/pad/
I_r 1 pA, C_r 0.8 pF
was state of the art at one time :-)
and maybe still "OK" for this application

node impedance ~ 1M so
1nA becomes 1mV offset.
= RS

Re: Moscaps? Any ideas?

<262a5a2d-a7ee-4a47-95a8-6a89c7b9ac72n@googlegroups.com>

copy mid

https://www.novabbs.com/tech/article-flat.php?id=107964&group=sci.electronics.design#107964

copy link Newsgroups: sci.electronics.design

X-Received: by 2002:ac8:5fcd:0:b0:35c:d514:eb86 with SMTP id k13-20020ac85fcd000000b0035cd514eb86mr5528976qta.616.1665774017823;
Fri, 14 Oct 2022 12:00:17 -0700 (PDT)
X-Received: by 2002:a05:620a:484c:b0:6ee:9acb:dfdc with SMTP id
ec12-20020a05620a484c00b006ee9acbdfdcmr4811241qkb.594.1665774017582; Fri, 14
Oct 2022 12:00:17 -0700 (PDT)
Path: i2pn2.org!i2pn.org!usenet.blueworldhosting.com!feed1.usenet.blueworldhosting.com!peer03.iad!feed-me.highwinds-media.com!news.highwinds-media.com!news-out.google.com!nntp.google.com!postnews.google.com!google-groups.googlegroups.com!not-for-mail
Newsgroups: sci.electronics.design
Date: Fri, 14 Oct 2022 12:00:17 -0700 (PDT)
In-Reply-To: <3b4jkh1a3cb1mh8m2303stq5ko9ck85vft@4ax.com>
Injection-Info: google-groups.googlegroups.com; posting-host=74.101.19.38; posting-account=rEo47AoAAAAz23oFFYoL4aHQauGkT8Lw
NNTP-Posting-Host: 74.101.19.38
References: <16Z1L.624898$iiS8.110148@fx17.iad> <b0bb6d6f-fa22-bcc2-79aa-787abb6d6316@electrooptical.net>
<jbugkhhilllgq9bp08jdfan69a3f4li48j@4ax.com> <_Vc2L.547243$6Il8.456716@fx14.iad>
<tibruc$258jn$1@dont-email.me> <3b4jkh1a3cb1mh8m2303stq5ko9ck85vft@4ax.com>
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <262a5a2d-a7ee-4a47-95a8-6a89c7b9ac72n@googlegroups.com>
Subject: Re: Moscaps? Any ideas?
From: richsuli...@gmail.com (Rich S)
Injection-Date: Fri, 14 Oct 2022 19:00:17 +0000
Content-Type: text/plain; charset="UTF-8"
X-Received-Bytes: 2008

by: Rich S - Fri, 14 Oct 2022 19:00 UTC

https://www.interfet.com/pad/
I_r 1 pA, C_r 0.8 pF
was state of the art at one time :-)
and maybe still "OK" for this application

node impedance ~ 1M so
1 pA becomes 1 uV offset.

= RS

Re: Moscaps? Any ideas?

<mjj2L.626135$iiS8.229005@fx17.iad>

copy mid

https://www.novabbs.com/tech/article-flat.php?id=107968&group=sci.electronics.design#107968

copy link Newsgroups: sci.electronics.design

Path: i2pn2.org!i2pn.org!usenet.blueworldhosting.com!feed1.usenet.blueworldhosting.com!peer01.iad!feed-me.highwinds-media.com!news.highwinds-media.com!fx17.iad.POSTED!not-for-mail
Subject: Re: Moscaps? Any ideas?
Newsgroups: sci.electronics.design
References: <16Z1L.624898$iiS8.110148@fx17.iad>
<b0bb6d6f-fa22-bcc2-79aa-787abb6d6316@electrooptical.net>
<jbugkhhilllgq9bp08jdfan69a3f4li48j@4ax.com>
<_Vc2L.547243$6Il8.456716@fx14.iad>
<p91jkhpcdsp4680aoqvfua8dr8825348r3@4ax.com>
From: Chipbee4...@yahoo.com (JC)
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101
Firefox/68.0 SeaMonkey/2.53.14
MIME-Version: 1.0
In-Reply-To: <p91jkhpcdsp4680aoqvfua8dr8825348r3@4ax.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Lines: 51
Message-ID: <mjj2L.626135$iiS8.229005@fx17.iad>
X-Complaints-To: abuse@easynews.com
Organization: Easynews - www.easynews.com
X-Complaints-Info: Please be sure to forward a copy of ALL headers otherwise we will be unable to process your complaint properly.
Date: Fri, 14 Oct 2022 16:06:42 -0400
X-Received-Bytes: 2658

by: JC - Fri, 14 Oct 2022 20:06 UTC

boB wrote:
> On Fri, 14 Oct 2022 08:50:05 -0400, JC <Chipbee40_SpamNo@yahoo.com>
> wrote:
>
>> John Larkin wrote:
>>> On Thu, 13 Oct 2022 16:40:18 -0400, Phil Hobbs
>>> <pcdhSpamMeSenseless@electrooptical.net> wrote:
>>>
>>>> JC wrote:
>>>>> Hi, Anyone care to explain what the function is of the 2 FETS Q1 and Q2
>>>>> in this Fluke calibrator and what might be the required parameters for a
>>>>> replacement?
>>>>>
>>>>> https://www.flickr.com/photos/40466580@N07/
>>>>>
>>>>> It fails diagnostics with leakage caused by one of these. At the moment
>>>>> I have them replaced with J210 FETS which I had to hand but I think
>>>>> there's maybe more to it than that. I cant find any data on them, they
>>>>> are marked IFC 07703
>>>>> TIA JC
>>>>
>>>> Protection diodes.
>>>>
>>>> Cheers
>>>>
>>>> Phil Hobbs
>>>
>>> Yes, jfets used as diodes. Terrible idea.
>>>
>>> The c-b junction of a small transistor would be better all-around.
>>> BFT25 has fA leakage... if you can get them. I could spare a few.
>>>
>>> There's probably a common TO92 transistor with sub-pA leakage.
>>>
>> Thanks for the replies.
>> JC
>
>
> I would think that if this was a Fluke designed circuit, that it
> wouldn't be something that wouldn't work.
>
> The people I know that work in the Fluke calibration engineering
> department are pretty smart.
>
> boB
>
I tend to agree and as this is an expensive repair/piece of gear
I think I might go with the PAD solution suggested by TV. They
are easily available and not that expensive in the world of Fluke parts :)
Thanks again for all the replies, much appreciated.
JC

Subject	Author
Moscaps? Any ideas?	JC
Re: Moscaps? Any ideas?	Phil Hobbs
Re: Moscaps? Any ideas?	John Larkin
Re: Moscaps? Any ideas?	Lasse Langwadt Christensen
Re: Moscaps? Any ideas?	Phil Hobbs
Re: Moscaps? Any ideas?	Lasse Langwadt Christensen
Re: Moscaps? Any ideas?	Phil Hobbs
Re: Moscaps? Any ideas?	JC
Re: Moscaps? Any ideas?	Tauno Voipio
Re: Moscaps? Any ideas?	John Larkin
Re: Moscaps? Any ideas?	Rich S
Re: Moscaps? Any ideas?	Rich S
Re: Moscaps? Any ideas?	boB
Re: Moscaps? Any ideas?	JC