Empathy List Archives

JS

Jim Stone

Wed, Aug 17, 2016 9:29 PM

Hi again,
The cable impedance measurement was in a different video (linked below) but
it can use the same HC14 TDR as in the first video. The concept is to just
put a pot on the end of the cable and adjust it until the reflection goes
away. Simple!

https://www.youtube.com/watch?v=Il_eju4D_TM

--Jim Stone

Hi Bob,
Take a look at this nice simple little one chip "TDR" and lesson on how to
use it to measure cable length and cable impedance. It uses a single AC14
(can use a DIP so no SMD needed) and gives a nice crisp 2 or 3 ns rise. The
AC family is nice fast logic and has been used in many Time-Nuts
application like cheap zero-cross detectors using the AC04.

https://www.youtube.com/watch?v=9cP6w2odGUc

Regards --Jim Stone

Bob Albert wrote:

Well I got my adapter boards from China and managed to build my first SMT
project, a square wave generator for TDR use. And it works! The IC seems
to run hot so I used my IR temperature measurement device and it checks out
at about 37C, acceptable. I can now drive a square wave at about 3 kHz
into 50 Ohms. The rise time isn't very short but I must have not used the
best part for the generator. Still, I can do some TDR experimenting as
long as the line isn't too short.
Thanks to all for the ideas and encouragement. I didn't use a microscope,
mostly just a magnifier. My tiniest soldering iron is a bit large but it
did the job.
Bob

Hi again, The cable impedance measurement was in a different video (linked below) but it can use the same HC14 TDR as in the first video. The concept is to just put a pot on the end of the cable and adjust it until the reflection goes away. Simple! https://www.youtube.com/watch?v=Il_eju4D_TM --Jim Stone Hi Bob, Take a look at this nice simple little one chip "TDR" and lesson on how to use it to measure cable length and cable impedance. It uses a single AC14 (can use a DIP so no SMD needed) and gives a nice crisp 2 or 3 ns rise. The AC family is nice fast logic and has been used in many Time-Nuts application like cheap zero-cross detectors using the AC04. https://www.youtube.com/watch?v=9cP6w2odGUc Regards --Jim Stone Bob Albert wrote: Well I got my adapter boards from China and managed to build my first SMT project, a square wave generator for TDR use. And it works! The IC seems to run hot so I used my IR temperature measurement device and it checks out at about 37C, acceptable. I can now drive a square wave at about 3 kHz into 50 Ohms. The rise time isn't very short but I must have not used the best part for the generator. Still, I can do some TDR experimenting as long as the line isn't too short. Thanks to all for the ideas and encouragement. I didn't use a microscope, mostly just a magnifier. My tiniest soldering iron is a bit large but it did the job. Bob

BA

Bob Albert

Thu, Aug 18, 2016 6:07 AM

Jim, that's the exact one I built! I rechecked and the rise time is about 2 ns, not longer as I previously reported. Not only do I have a new piece of test gear but I have gotten some SMT experience. Previously I have removed chips but this is the first time I have installed one. I didn't use the liquid solder because I didn't have any and it doesn't keep very long. I used ordinary solder with a small iron and it worked well, although I didn't have as much control as I wished.
I also have a SNA that can be used for some of the same measurements but this thing is simple. I checked both with my digital HP scope and my analog Tek and got the same result.
I checked a three foot piece of coax, both open at the far end and shorted there, and got the textbook waveforms. I love it when the basics check out.
Bob

On Wednesday, August 17, 2016 11:00 PM, Jim Stone <tictocnut@gmail.com> wrote:

Hi again,
The cable impedance measurement was in a different video (linked below) but
it can use the same HC14 TDR as in the first video. The concept is to just
put a pot on the end of the cable and adjust it until the reflection goes
away. Simple!

https://www.youtube.com/watch?v=Il_eju4D_TM

--Jim Stone

Hi Bob,
Take a look at this nice simple little one chip "TDR" and lesson on how to
use it to measure cable length and cable impedance. It uses a single AC14
(can use a DIP so no SMD needed) and gives a nice crisp 2 or 3 ns rise. The
AC family is nice fast logic and has been used in many Time-Nuts
application like cheap zero-cross detectors using the AC04.

https://www.youtube.com/watch?v=9cP6w2odGUc

Regards --Jim Stone

Bob Albert wrote:

Well I got my adapter boards from China and managed to build my first SMT
project, a square wave generator for TDR use. And it works! The IC seems
to run hot so I used my IR temperature measurement device and it checks out
at about 37C, acceptable. I can now drive a square wave at about 3 kHz
into 50 Ohms. The rise time isn't very short but I must have not used the
best part for the generator. Still, I can do some TDR experimenting as
long as the line isn't too short.
Thanks to all for the ideas and encouragement. I didn't use a microscope,
mostly just a magnifier. My tiniest soldering iron is a bit large but it
did the job.
Bob

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.

Jim, that's the exact one I built! I rechecked and the rise time is about 2 ns, not longer as I previously reported. Not only do I have a new piece of test gear but I have gotten some SMT experience. Previously I have removed chips but this is the first time I have installed one. I didn't use the liquid solder because I didn't have any and it doesn't keep very long. I used ordinary solder with a small iron and it worked well, although I didn't have as much control as I wished. I also have a SNA that can be used for some of the same measurements but this thing is simple. I checked both with my digital HP scope and my analog Tek and got the same result. I checked a three foot piece of coax, both open at the far end and shorted there, and got the textbook waveforms. I love it when the basics check out. Bob On Wednesday, August 17, 2016 11:00 PM, Jim Stone <tictocnut@gmail.com> wrote: Hi again, The cable impedance measurement was in a different video (linked below) but it can use the same HC14 TDR as in the first video. The concept is to just put a pot on the end of the cable and adjust it until the reflection goes away. Simple! https://www.youtube.com/watch?v=Il_eju4D_TM --Jim Stone Hi Bob, Take a look at this nice simple little one chip "TDR" and lesson on how to use it to measure cable length and cable impedance. It uses a single AC14 (can use a DIP so no SMD needed) and gives a nice crisp 2 or 3 ns rise. The AC family is nice fast logic and has been used in many Time-Nuts application like cheap zero-cross detectors using the AC04. https://www.youtube.com/watch?v=9cP6w2odGUc Regards --Jim Stone Bob Albert wrote: Well I got my adapter boards from China and managed to build my first SMT project, a square wave generator for TDR use. And it works! The IC seems to run hot so I used my IR temperature measurement device and it checks out at about 37C, acceptable. I can now drive a square wave at about 3 kHz into 50 Ohms. The rise time isn't very short but I must have not used the best part for the generator. Still, I can do some TDR experimenting as long as the line isn't too short. Thanks to all for the ideas and encouragement. I didn't use a microscope, mostly just a magnifier. My tiniest soldering iron is a bit large but it did the job. Bob _______________________________________________ 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.

SW

Steve Wiseman

Thu, Aug 18, 2016 9:25 AM

On 18 August 2016 at 07:07, Bob Albert via time-nuts time-nuts@febo.com wrote:

I didn't use the liquid solder because I didn't have any and it doesn't keep very long.

That's not really the case. It may change consistency so that it
behaves a little differently and fouls up automated stencilling
machines (which are the most finicky devices on the planet), but with
a human in the loop, you can expect most of a decade unless you let
it dry out or do something daft.
I'm still happily using stuff with a 2007 expiry code, in (big)
plastic syringes. Still behaves fine. (and the benefit of the
stirred-in flux and excellent wetting does make paste a joy to use
compared to even good solder wire).
'Expired' solder paste can be a bargain.

Steve

On 18 August 2016 at 07:07, Bob Albert via time-nuts <time-nuts@febo.com> wrote: > I didn't use the liquid solder because I didn't have any and it doesn't keep very long. That's not really the case. It may change consistency so that it behaves a little differently and fouls up automated stencilling machines (which are the most finicky devices on the planet), but with a human in the loop, you can expect most of a decade unless you let it dry out or do something daft. I'm still happily using stuff with a 2007 expiry code, in (big) plastic syringes. Still behaves fine. (and the benefit of the stirred-in flux and excellent wetting does make paste a joy to use compared to even good solder wire). 'Expired' solder paste can be a bargain. Steve

BA

Bob Albert

Thu, Aug 18, 2016 5:36 PM

Ah Steve, that's good info! Now where does one buy expired solder paste? And what's the proper name for it - solder paste searches mostly come up with just flux.

Bob

On Thursday, August 18, 2016 2:25 AM, Steve Wiseman <sjwiseman@gmail.com> wrote:

On 18 August 2016 at 07:07, Bob Albert via time-nuts time-nuts@febo.com wrote:

I didn't use the liquid solder because I didn't have any and it doesn't keep very long.

That's not really the case. It may change consistency so that it
behaves a little differently and fouls up automated stencilling
machines (which are the most finicky devices on the planet), but with
a human in the loop, you can expect most of a decade unless you let
it dry out or do something daft.
I'm still happily using stuff with a 2007 expiry code, in (big)
plastic syringes. Still behaves fine. (and the benefit of the
stirred-in flux and excellent wetting does make paste a joy to use
compared to even good solder wire).
'Expired' solder paste can be a bargain.

Steve

Ah Steve, that's good info! Now where does one buy expired solder paste? And what's the proper name for it - solder paste searches mostly come up with just flux. Bob On Thursday, August 18, 2016 2:25 AM, Steve Wiseman <sjwiseman@gmail.com> wrote: On 18 August 2016 at 07:07, Bob Albert via time-nuts <time-nuts@febo.com> wrote: > I didn't use the liquid solder because I didn't have any and it doesn't keep very long. That's not really the case. It may change consistency so that it behaves a little differently and fouls up automated stencilling machines (which are the most finicky devices on the planet), but with a human in the loop, you can expect most of a decade unless you let it dry out or do something daft. I'm still happily using stuff with a 2007 expiry code, in (big) plastic syringes. Still behaves fine. (and the benefit of the stirred-in flux and excellent wetting does make paste a joy to use compared to even good solder wire). 'Expired' solder paste can be a bargain. Steve

CH

Chuck Harris

Thu, Aug 18, 2016 6:50 PM

I have had similar experience with well expired paste.

I just don't worry about it.

The issue is the solder is ground to such a fine powder that
it has a huge surface area to oxidize. As long as you keep
the air off, and refrigerate the paste, it seems to go forever.

Oh, and I only use tin/lead paste, not the RoHS stuff.

-Chuck Harris

Steve Wiseman wrote:

On 18 August 2016 at 07:07, Bob Albert via time-nuts time-nuts@febo.com wrote:

I didn't use the liquid solder because I didn't have any and it doesn't keep very long.

That's not really the case. It may change consistency so that it
behaves a little differently and fouls up automated stencilling
machines (which are the most finicky devices on the planet), but with
a human in the loop, you can expect most of a decade unless you let
it dry out or do something daft.
I'm still happily using stuff with a 2007 expiry code, in (big)
plastic syringes. Still behaves fine. (and the benefit of the
stirred-in flux and excellent wetting does make paste a joy to use
compared to even good solder wire).
'Expired' solder paste can be a bargain.

Steve

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.

I have had similar experience with well expired paste. I just don't worry about it. The issue is the solder is ground to such a fine powder that it has a huge surface area to oxidize. As long as you keep the air off, and refrigerate the paste, it seems to go forever. Oh, and I only use tin/lead paste, not the RoHS stuff. -Chuck Harris Steve Wiseman wrote: > On 18 August 2016 at 07:07, Bob Albert via time-nuts <time-nuts@febo.com> wrote: >> I didn't use the liquid solder because I didn't have any and it doesn't keep very long. > > That's not really the case. It may change consistency so that it > behaves a little differently and fouls up automated stencilling > machines (which are the most finicky devices on the planet), but with > a human in the loop, you can expect most of a decade unless you let > it dry out or do something daft. > I'm still happily using stuff with a 2007 expiry code, in (big) > plastic syringes. Still behaves fine. (and the benefit of the > stirred-in flux and excellent wetting does make paste a joy to use > compared to even good solder wire). > 'Expired' solder paste can be a bargain. > > Steve > _______________________________________________ > 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. >

BA

Bob Albert

Thu, Aug 18, 2016 7:11 PM

So where do you get this expired paste? I have tried a few searches but no luck.
Bob

On Thursday, August 18, 2016 12:00 PM, Chuck Harris <cfharris@erols.com> wrote:

I have had similar experience with well expired paste.

I just don't worry about it.

The issue is the solder is ground to such a fine powder that
it has a huge surface area to oxidize. As long as you keep
the air off, and refrigerate the paste, it seems to go forever.

Oh, and I only use tin/lead paste, not the RoHS stuff.

-Chuck Harris

Steve Wiseman wrote:

On 18 August 2016 at 07:07, Bob Albert via time-nuts time-nuts@febo.com wrote:

I didn't use the liquid solder because I didn't have any and it doesn't keep very long.

That's not really the case. It may change consistency so that it
behaves a little differently and fouls up automated stencilling
machines (which are the most finicky devices on the planet), but with
a human in the loop, you can expect most of a decade unless you let
it dry out or do something daft.
I'm still happily using stuff with a 2007 expiry code, in (big)
plastic syringes. Still behaves fine. (and the benefit of the
stirred-in flux and excellent wetting does make paste a joy to use
compared to even good solder wire).
'Expired' solder paste can be a bargain.

Steve

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.

So where do you get this expired paste? I have tried a few searches but no luck. Bob On Thursday, August 18, 2016 12:00 PM, Chuck Harris <cfharris@erols.com> wrote: I have had similar experience with well expired paste. I just don't worry about it. The issue is the solder is ground to such a fine powder that it has a huge surface area to oxidize. As long as you keep the air off, and refrigerate the paste, it seems to go forever. Oh, and I only use tin/lead paste, not the RoHS stuff. -Chuck Harris Steve Wiseman wrote: > On 18 August 2016 at 07:07, Bob Albert via time-nuts <time-nuts@febo.com> wrote: >> I didn't use the liquid solder because I didn't have any and it doesn't keep very long. > > That's not really the case. It may change consistency so that it > behaves a little differently and fouls up automated stencilling > machines (which are the most finicky devices on the planet), but with > a human in the loop, you can expect most of a decade unless you let > it dry out or do something daft. > I'm still happily using stuff with a 2007 expiry code, in (big) > plastic syringes. Still behaves fine. (and the benefit of the > stirred-in flux and excellent wetting does make paste a joy to use > compared to even good solder wire). > 'Expired' solder paste can be a bargain. > > Steve > _______________________________________________ > 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. > _______________________________________________ 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.

CH

Chuck Harris

Thu, Aug 18, 2016 10:16 PM

Uhmmm, I buy it new, and expire it myself... blush.

-Chuck Harris

Bob Albert via time-nuts wrote:

So where do you get this expired paste? I have tried a few searches but no luck.
Bob

Uhmmm, I buy it new, and expire it myself... blush. -Chuck Harris Bob Albert via time-nuts wrote: > So where do you get this expired paste? I have tried a few searches but no luck. > Bob

time-nuts@lists.febo.com

Re: [time-nuts] Subject: Re: Working with SMT parts (Bob Albert)