[time-nuts] Fw: What's the latest correct PICTIC II Mouserproject?-Heathkid

[Heathkid]

Thanks Stanley,

I placed the Mouser order tonight (based on Bob Camp's "project" he 
updated).  I'm no expert either... but I'd still like to know what are the 
best options for an enclosure and external connectors...  The rest I'll 
leave up to it all being relative and it is what it is...

73 Brice KA8MAV

----- Original Message ----- 
From: "Stanley Reynolds" <stanley_reynolds at yahoo.com>
To: <time-nuts at febo.com>
Sent: Saturday, August 14, 2010 12:56 PM
Subject: [time-nuts] Fw: What's the latest correct PICTIC II 
Mouserproject?-Heathkid



Duplicate message without in-line picture.


----- Forwarded Message ----
From: Stanley Reynolds <stanley_reynolds at yahoo.com>
To: Discussion of precise time and frequency measurement 
<time-nuts at febo.com>
Sent: Sat, August 14, 2010 11:41:36 AM
Subject: Re: [time-nuts] What's the latest correct PICTIC II Mouserproject?-
Heathkid


1) I have no previous experience building precision anything, I'm not an 
expert.

2) My guess is the design expects quality components and depends on the auto
calibration to correct any component drift.

Short term stability between calibrations is what we want. The absolute 
value of

C16 and C17 is not as important as it's stability in leakage and value.


Guess we could put the didoes in a constant temp oven but not sure all the
components are more stable at higher temps.

Good ideas about didoes here :
http://www.sciencebuddies.org/science-fair-projects/project_ideas/Elec_p033.shtml


(note Figure 3 and how the didoes voltage drop is more linear at higher 
temps vs

room temp.)

Stanley





________________________________
From: Heathkid <heathkid at heathkid.com>
To: Discussion of precise time and frequency measurement 
<time-nuts at febo.com>
Sent: Sat, August 14, 2010 10:43:15 AM
Subject: Re: [time-nuts] What's the latest correct PICTIC II Mouserproject?-
Heathkid

Okay Stanley... I've got a Tektronix 370A curve tracer at work. So the 
diodes
need to be matched? No problem.

So I match the diodes and the resistors to within 0.001%. Are there any 
other
components that need matched? Also, you mentioned using hemostats as 
heatsinks
on the diodes while installing them. I know that diodes make very good
temperature sensors as well. Are there any suggestions on keeping them 
stable
after they are on the board? What is the recommended operating temperature 
of
the PICTIC II?

Thanks.

73 Brice KA8MAV

----- Original Message ----- From: "Stanley Reynolds"
<stanley_reynolds at yahoo.com>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Saturday, August 14, 2010 10:43 AM
Subject: Re: [time-nuts] What's the latest correct PICTIC II Mouserproject?-
Heathkid


<snip>

Maybe we should buy lots of diodes to match them, they are relative cheap, 
also
use extra care installing them. Using hemostats as heat sinks and just 
enough
heat for a good connection do not want to damage/change them after the 
match.

Stanley

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