Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of semiconductors and make designing for same much more predictable and dependable than relying on spice models and simulation alone. But they're typically rare beasts and expensive to come by and boat anchor varieties
are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project, using the X&Y inputs of a scope as the display. Has anyone here attempted this? I'd be interested to know what the main challenges are likely to be.
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of >semiconductors and make designing for same much more predictable and >dependable than relying on spice models and simulation alone. But they're >typically rare beasts and expensive to come by and boat anchor varieties
are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project,
using the X&Y inputs of a scope as the display. Has anyone here attempted >this? I'd be interested to know what the main challenges are likely to be.
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of >semiconductors and make designing for same much more predictable and >dependable than relying on spice models and simulation alone. But they're >typically rare beasts and expensive to come by and boat anchor varieties
are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project,
using the X&Y inputs of a scope as the display. Has anyone here attempted >this? I'd be interested to know what the main challenges are likely to be.
-CD
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of semiconductors and make designing for same much more predictable and dependable than relying on spice models and simulation alone. But they're typically rare beasts and expensive to come by and boat anchor varieties
are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project, using the X&Y inputs of a scope as the display. Has anyone here attempted this? I'd be interested to know what the main challenges are likely to be.
-CD
On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of
semiconductors and make designing for same much more predictable and
dependable than relying on spice models and simulation alone. But they're
typically rare beasts and expensive to come by and boat anchor varieties
are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project,
using the X&Y inputs of a scope as the display. Has anyone here attempted
this? I'd be interested to know what the main challenges are likely to be. >>
-CD
I've considered it. It would be much more valuable if it traced
capacitances too.
The display should be on a computer and the data archived.
I often just set up a breadboard and test parts. Last week I blew out
some power mosfet gates. Some have internal zeners; this one doesn't.
Most mosfets drain avalanche, but the voltage is never specified, in
fact deliberately hidden. I have to measure that. A good curve tracer
should measure that too.
Currents should go down to picoamps.
The fact that there aren't many curve tracers for sale suggests a
small market.
On 11/20/2024 10:40 AM, john larkin wrote:
On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of
semiconductors and make designing for same much more predictable and
dependable than relying on spice models and simulation alone. But they're >>> typically rare beasts and expensive to come by and boat anchor varieties >>> are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project,
using the X&Y inputs of a scope as the display. Has anyone here attempted >>> this? I'd be interested to know what the main challenges are likely to be. >>>
-CD
I've considered it. It would be much more valuable if it traced
capacitances too.
The display should be on a computer and the data archived.
I often just set up a breadboard and test parts. Last week I blew out
some power mosfet gates. Some have internal zeners; this one doesn't.
Most mosfets drain avalanche, but the voltage is never specified, in
fact deliberately hidden. I have to measure that. A good curve tracer
should measure that too.
Currents should go down to picoamps.
The fact that there aren't many curve tracers for sale suggests a
small market.
Meanwhile, in China:
<https://www.amazon.com/Transistor-Tracer-Feature-Graphic-Instrument/dp/B0D25RDFDV>
Someone seems to still banging out 1970s-style CTs
Meanwhile, in China:
<https://www.amazon.com/Transistor-Tracer-Feature-Graphic-Instrument/dp/B0D25RDFDV>
Someone seems to still banging out 1970s-style CTs
Barbaric.
On 11/20/2024 10:58 AM, john larkin wrote:
Meanwhile, in China:
<https://www.amazon.com/Transistor-Tracer-Feature-Graphic-Instrument/dp/B0D25RDFDV>
Someone seems to still banging out 1970s-style CTs
Barbaric.
Last chance buy before tariffs kick in and HP re-instates its whole 1987 >catalog to meet the demand for domestically-produced test gear.
On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom ><cd999666@notformail.com> wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of >>semiconductors and make designing for same much more predictable and >>dependable than relying on spice models and simulation alone. But they're >>typically rare beasts and expensive to come by and boat anchor varieties >>are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project, >>using the X&Y inputs of a scope as the display. Has anyone here attempted >>this? I'd be interested to know what the main challenges are likely to be.
-CD
I've considered it. It would be much more valuable if it traced
capacitances too.
The display should be on a computer and the data archived.
I often just set up a breadboard and test parts. Last week I blew out
some power mosfet gates. Some have internal zeners; this one doesn't.
Most mosfets drain avalanche, but the voltage is never specified, in
fact deliberately hidden. I have to measure that. A good curve tracer
should measure that too.
Currents should go down to picoamps.
The fact that there aren't many curve tracers for sale suggests a
small market.
On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of >>semiconductors and make designing for same much more predictable and >>dependable than relying on spice models and simulation alone. But
they're typically rare beasts and expensive to come by and boat anchor >>varieties are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project, >>using the X&Y inputs of a scope as the display. Has anyone here
attempted this? I'd be interested to know what the main challenges are >>likely to be.
-CD
I've considered it. It would be much more valuable if it traced
capacitances too.
The display should be on a computer and the data archived.
I often just set up a breadboard and test parts. Last week I blew out
some power mosfet gates. Some have internal zeners; this one doesn't.
Most mosfets drain avalanche, but the voltage is never specified, in
fact deliberately hidden. I have to measure that. A good curve tracer
should measure that too.
Currents should go down to picoamps.
The fact that there aren't many curve tracers for sale suggests a small market.
On 11/20/2024 10:58 AM, john larkin wrote:
Last chance buy before tariffs kick in and HP re-instates its whole 1987 catalog to meet the demand for domestically-produced test gear.Meanwhile, in China:
<https://www.amazon.com/Transistor-Tracer-Feature-Graphic-Instrument/ dp/B0D25RDFDV>
Someone seems to still banging out 1970s-style CTs
Barbaric.
On 11/20/2024 6:32 AM, Cursitor Doom wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of
semiconductors and make designing for same much more predictable and
dependable than relying on spice models and simulation alone. But
they're typically rare beasts and expensive to come by and boat anchor
varieties are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent
project,
using the X&Y inputs of a scope as the display. Has anyone here
attempted this? I'd be interested to know what the main challenges are
likely to be.
-CD
A bit more modern way to do this is get one of those HP data acquisition units like a 34970A with a multiplexer card, and a multi-output PSU that
can both be controlled over GP-IB
On Wed, 20 Nov 2024 11:02:49 -0500, bitrex <user@example.net> wrote:
On 11/20/2024 10:58 AM, john larkin wrote:
Last chance buy before tariffs kick in and HP re-instates its whole 1987 >>catalog to meet the demand for domestically-produced test gear.Meanwhile, in China:
<https://www.amazon.com/Transistor-Tracer-Feature-Graphic-Instrument/ dp/B0D25RDFDV>
Someone seems to still banging out 1970s-style CTs
Barbaric.
You buy one. Give us a review.
On Wed, 20 Nov 2024 11:02:49 -0500, bitrex wrote:
On 11/20/2024 10:58 AM, john larkin wrote:dp/B0D25RDFDV>
Meanwhile, in China:
<https://www.amazon.com/Transistor-Tracer-Feature-Graphic-Instrument/
Last chance buy before tariffs kick in and HP re-instates its whole 1987
Someone seems to still banging out 1970s-style CTs
Barbaric.
catalog to meet the demand for domestically-produced test gear.
Yes, Trump may well be throwing them a lifeline. HP products might once
again be craned and fork-lifted into RF developers' labs across the
nation!
I can't see any price listed for the Chinese CT for some reason. Any idea
how much it is?
On Wed, 20 Nov 2024 07:40:08 -0800, john larkin <JL@gct.com> wrote:
On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of
semiconductors and make designing for same much more predictable and
dependable than relying on spice models and simulation alone. But they're >>> typically rare beasts and expensive to come by and boat anchor varieties >>> are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project,
using the X&Y inputs of a scope as the display. Has anyone here attempted >>> this? I'd be interested to know what the main challenges are likely to be. >>>
-CD
I've considered it. It would be much more valuable if it traced
capacitances too.
The display should be on a computer and the data archived.
I often just set up a breadboard and test parts. Last week I blew out
some power mosfet gates. Some have internal zeners; this one doesn't.
Most mosfets drain avalanche, but the voltage is never specified, in
fact deliberately hidden. I have to measure that. A good curve tracer
should measure that too.
Currents should go down to picoamps.
The fact that there aren't many curve tracers for sale suggests a
small market.
I think that the function is now done by a Fluke Data Bucket (or
equivalent) in an ATE (Automatic Test Equipment) that controls
collection of data, which is later plotted in a computer.
Joe Gwinn
On Wed, 20 Nov 2024 08:41:19 -0800, john larkin wrote:
On Wed, 20 Nov 2024 11:02:49 -0500, bitrex <user@example.net> wrote:
On 11/20/2024 10:58 AM, john larkin wrote:
Last chance buy before tariffs kick in and HP re-instates its whole 1987 >>>catalog to meet the demand for domestically-produced test gear.Meanwhile, in China:
<https://www.amazon.com/Transistor-Tracer-Feature-Graphic-Instrument/ >dp/B0D25RDFDV>
Someone seems to still banging out 1970s-style CTs
Barbaric.
You buy one. Give us a review.
Perhaps you should consider developing one for production purposes?
Joe Gwinn <joegwinn@comcast.net> wrote:
On Wed, 20 Nov 2024 07:40:08 -0800, john larkin <JL@gct.com> wrote:
On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of
semiconductors and make designing for same much more predictable and
dependable than relying on spice models and simulation alone. But they're >>>> typically rare beasts and expensive to come by and boat anchor varieties >>>> are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project, >>>> using the X&Y inputs of a scope as the display. Has anyone here attempted >>>> this? I'd be interested to know what the main challenges are likely to be. >>>>
-CD
I've considered it. It would be much more valuable if it traced
capacitances too.
The display should be on a computer and the data archived.
I often just set up a breadboard and test parts. Last week I blew out
some power mosfet gates. Some have internal zeners; this one doesn't.
Most mosfets drain avalanche, but the voltage is never specified, in
fact deliberately hidden. I have to measure that. A good curve tracer
should measure that too.
Currents should go down to picoamps.
The fact that there aren't many curve tracers for sale suggests a
small market.
I think that the function is now done by a Fluke Data Bucket (or
equivalent) in an ATE (Automatic Test Equipment) that controls
collection of data, which is later plotted in a computer.
Joe Gwinn
Nah, real men use an HP 4145B. Exceptionally Good Medicine.
On Wed, 20 Nov 2024 07:40:08 -0800, john larkin wrote:
On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of >>>semiconductors and make designing for same much more predictable and >>>dependable than relying on spice models and simulation alone. But
they're typically rare beasts and expensive to come by and boat anchor >>>varieties are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project, >>>using the X&Y inputs of a scope as the display. Has anyone here
attempted this? I'd be interested to know what the main challenges are >>>likely to be.
-CD
I've considered it. It would be much more valuable if it traced
capacitances too.
A VNA is best for that. I've been using my big HP one this afternoon to
label some random bunches of caps and inductors whose values I couldn't
read. Trouble is, there doesn't seem to be much agreement on what
frequency to test these devices at. I've heard 100khz, 1Mhz, 10Mhz and
100Mhz mentioned from different sources. I'm pretty sure the 100Mhz
testing is for RF specified devices only, though. From what I've seen, >there's no reliable alternative to testing each batch for oneself, because >(certainly with ancient NOS leaded (as in non-SMD) stock) you have no idea >what frequency the factory tested them at and different manufacturers in >different countries at different times used different methods!
The display should be on a computer and the data archived.
For people such as yourself, certainly. For me as a hobbyist, a CRT is
fine.
I often just set up a breadboard and test parts. Last week I blew out
some power mosfet gates. Some have internal zeners; this one doesn't.
I can kill a MOSFET at 50' just by looking at it (certainly in winter). In >fact I shock myself from all the static I build up and it ain't funny.
Having dry skin is great for when I touch HV by accident (happens quite a >lot) but the flip side is I accumulate and hold static charge like no one >else I know.
Most mosfets drain avalanche, but the voltage is never specified, in
fact deliberately hidden. I have to measure that. A good curve tracer
should measure that too.
Currents should go down to picoamps.
The fact that there aren't many curve tracers for sale suggests a small
market.
But a market, though small perhaps, there must be.
On Wed, 20 Nov 2024 11:02:49 -0500, bitrex wrote:
On 11/20/2024 10:58 AM, john larkin wrote:
Last chance buy before tariffs kick in and HP re-instates its whole 1987Meanwhile, in China:
<https://www.amazon.com/Transistor-Tracer-Feature-Graphic-Instrument/ >dp/B0D25RDFDV>
Someone seems to still banging out 1970s-style CTs
Barbaric.
catalog to meet the demand for domestically-produced test gear.
Yes, Trump may well be throwing them a lifeline. HP products might once
again be craned and fork-lifted into RF developers' labs across the
nation!
I can't see any price listed for the Chinese CT for some reason. Any idea
how much it is?
On 11/20/2024 6:32 AM, Cursitor Doom wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of
semiconductors and make designing for same much more predictable and
dependable than relying on spice models and simulation alone. But they're
typically rare beasts and expensive to come by and boat anchor varieties
are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project,
using the X&Y inputs of a scope as the display. Has anyone here attempted
this? I'd be interested to know what the main challenges are likely to be. >>
-CD
A bit more modern way to do this is get one of those HP data acquisition >units like a 34970A with a multiplexer card, and a multi-output PSU that
can both be controlled over GP-IB
On Wed, 20 Nov 2024 18:46:03 -0000 (UTC), Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
Joe Gwinn <joegwinn@comcast.net> wrote:
On Wed, 20 Nov 2024 07:40:08 -0800, john larkin <JL@gct.com> wrote:
On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of >>>>> semiconductors and make designing for same much more predictable and >>>>> dependable than relying on spice models and simulation alone. But they're >>>>> typically rare beasts and expensive to come by and boat anchor varieties >>>>> are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project, >>>>> using the X&Y inputs of a scope as the display. Has anyone here attempted >>>>> this? I'd be interested to know what the main challenges are likely to be.
-CD
I've considered it. It would be much more valuable if it traced
capacitances too.
The display should be on a computer and the data archived.
I often just set up a breadboard and test parts. Last week I blew out
some power mosfet gates. Some have internal zeners; this one doesn't.
Most mosfets drain avalanche, but the voltage is never specified, in
fact deliberately hidden. I have to measure that. A good curve tracer >>>> should measure that too.
Currents should go down to picoamps.
The fact that there aren't many curve tracers for sale suggests a
small market.
I think that the function is now done by a Fluke Data Bucket (or
equivalent) in an ATE (Automatic Test Equipment) that controls
collection of data, which is later plotted in a computer.
Joe Gwinn
Nah, real men use an HP 4145B. Exceptionally Good Medicine.
Heh. Boat anchor for sure. But it had real knobs, and no Windows.
And isn't it a bit limited - only tests old semiconductors ...
Joe
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of semiconductors and make designing for same much more predictable and dependable than relying on spice models and simulation alone. But they're typically rare beasts and expensive to come by and boat anchor varieties
are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project, using the X&Y inputs of a scope as the display. Has anyone here attempted this? I'd be interested to know what the main challenges are likely to be.
On Wed, 20 Nov 2024 18:00:34 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 07:40:08 -0800, john larkin wrote:
On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of
semiconductors and make designing for same much more predictable and
dependable than relying on spice models and simulation alone. But
they're typically rare beasts and expensive to come by and boat anchor >>>> varieties are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project, >>>> using the X&Y inputs of a scope as the display. Has anyone here
attempted this? I'd be interested to know what the main challenges are >>>> likely to be.
-CD
I've considered it. It would be much more valuable if it traced
capacitances too.
A VNA is best for that. I've been using my big HP one this afternoon to
label some random bunches of caps and inductors whose values I couldn't
read. Trouble is, there doesn't seem to be much agreement on what
frequency to test these devices at. I've heard 100khz, 1Mhz, 10Mhz and
100Mhz mentioned from different sources. I'm pretty sure the 100Mhz
testing is for RF specified devices only, though. From what I've seen,
there's no reliable alternative to testing each batch for oneself, because >> (certainly with ancient NOS leaded (as in non-SMD) stock) you have no idea >> what frequency the factory tested them at and different manufacturers in
different countries at different times used different methods!
What I want is C-V curves. I guess a VNA can do that with a some bias
tees and various power supplies.
The display should be on a computer and the data archived.
For people such as yourself, certainly. For me as a hobbyist, a CRT is
fine.
You have to read the analog screen and write down numbers. Or take a
picture.
I often just set up a breadboard and test parts. Last week I blew out
some power mosfet gates. Some have internal zeners; this one doesn't.
I can kill a MOSFET at 50' just by looking at it (certainly in winter). In >> fact I shock myself from all the static I build up and it ain't funny.
Having dry skin is great for when I touch HV by accident (happens quite a
lot) but the flip side is I accumulate and hold static charge like no one
else I know.
Some fets have protective gate zeners. They typically clamp at +-40
volts.
Here in San Francisco, we never get static zapped. High humidity.
I think therefore that a curve tracer would make an excellent project,
using the X&Y inputs of a scope as the display. Has anyone here attempted >this? I'd be interested to know what the main challenges are likely to be.
Joe Gwinn <joegwinn@comcast.net> wrote:
On Wed, 20 Nov 2024 07:40:08 -0800, john larkin <JL@gct.com> wrote:Nah, real men use an HP 4145B. Exceptionally Good Medicine.
On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of
semiconductors and make designing for same much more predictable and
dependable than relying on spice models and simulation alone. But
they're typically rare beasts and expensive to come by and boat
anchor varieties are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent
project, using the X&Y inputs of a scope as the display. Has anyone
here attempted this? I'd be interested to know what the main
challenges are likely to be.
-CD
I've considered it. It would be much more valuable if it traced
capacitances too.
The display should be on a computer and the data archived.
I often just set up a breadboard and test parts. Last week I blew out
some power mosfet gates. Some have internal zeners; this one doesn't.
Most mosfets drain avalanche, but the voltage is never specified, in
fact deliberately hidden. I have to measure that. A good curve tracer
should measure that too.
Currents should go down to picoamps.
The fact that there aren't many curve tracers for sale suggests a
small market.
I think that the function is now done by a Fluke Data Bucket (or
equivalent) in an ATE (Automatic Test Equipment) that controls
collection of data, which is later plotted in a computer.
Joe Gwinn
Cheers
On Wed, 20 Nov 2024 18:00:34 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 07:40:08 -0800, john larkin wrote:
On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of >>>>semiconductors and make designing for same much more predictable and >>>>dependable than relying on spice models and simulation alone. But >>>>they're typically rare beasts and expensive to come by and boat anchor >>>>varieties are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent
project,
using the X&Y inputs of a scope as the display. Has anyone here >>>>attempted this? I'd be interested to know what the main challenges are >>>>likely to be.
-CD
I've considered it. It would be much more valuable if it traced
capacitances too.
A VNA is best for that. I've been using my big HP one this afternoon to >>label some random bunches of caps and inductors whose values I couldn't >>read. Trouble is, there doesn't seem to be much agreement on what
frequency to test these devices at. I've heard 100khz, 1Mhz, 10Mhz and >>100Mhz mentioned from different sources. I'm pretty sure the 100Mhz
testing is for RF specified devices only, though. From what I've seen, >>there's no reliable alternative to testing each batch for oneself,
because (certainly with ancient NOS leaded (as in non-SMD) stock) you
have no idea what frequency the factory tested them at and different >>manufacturers in different countries at different times used different >>methods!
What I want is C-V curves. I guess a VNA can do that with a some bias
tees and various power supplies.
The display should be on a computer and the data archived.
For people such as yourself, certainly. For me as a hobbyist, a CRT is >>fine.
You have to read the analog screen and write down numbers. Or take a
picture.
I often just set up a breadboard and test parts. Last week I blew out
some power mosfet gates. Some have internal zeners; this one doesn't.
I can kill a MOSFET at 50' just by looking at it (certainly in winter).
In fact I shock myself from all the static I build up and it ain't
funny. Having dry skin is great for when I touch HV by accident (happens >>quite a lot) but the flip side is I accumulate and hold static charge
like no one else I know.
Some fets have protective gate zeners. They typically clamp at +-40
volts.
Here in San Francisco, we never get static zapped. High humidity.
Most mosfets drain avalanche, but the voltage is never specified, in
fact deliberately hidden. I have to measure that. A good curve tracer
should measure that too.
Currents should go down to picoamps.
The fact that there aren't many curve tracers for sale suggests a
small market.
But a market, though small perhaps, there must be.
Sure. It would be a fun project.
In article <vhkhcg$2ip8$2@dont-email.me>,sl=nl&tl=en&js=y&prev=_t&hl=nl&ie=UTF-8&u=https%3A%2F%2Fwww.circuitsonline.net%2Fforum%2Fview%2F141079&edit-
Cursitor Doom <cd999666@notformail.com> wrote:
I think therefore that a curve tracer would make an excellent project, >>using the X&Y inputs of a scope as the display. Has anyone here
attempted this? I'd be interested to know what the main challenges are >>likely to be.
One of the challenges is the tradeoff between power and safety. If you design the tracer to be very-safe for small-signal devices (limited
voltage and current delivery ranges) then it won't be suitable for
tracing power semiconductors. Make it beefy enough for big parts, and
one slight misadjustment of a switch will turn a small-signal
semiconductor into cheap or expensive vapor.
It's a multi-variable optimization problem (voltage and current range
and limiting, tracing speed, cost, and operator skill) and I suspect
there's nothing like a single right answer. Ya pays yer money and ya
chooses yer limitations (or amount of shrapnel).
https://www.eevblog.com/forum/testgear/fooln-around-with-dso-awg/
https://translate.google.com/translate?
https://www-pa4tim-nl.translate.goog/?p=1437&_x_tr_sl=nl&_x_tr_tl=en&_x_tr_hl=nl
The SDG 2042X mentioned in the first article, and its faster cousins can
be controlled via SCPI. It has voltage and current output capability
good enough to test small-signal transistors on its own,
and you can hook it to an external two-channel power amplifier and gain
stage to test heftier parts.
A lot of inexpensive digital-storage oscilloscopes also support SCPI
control. So, you could automate a lot of the setup and testing, and
even capture the DSO screen image (or upload the two-channel data
traces, and re-plot them on your computer).
Many people feel that older analog scopes work better in X/Y mode than
any of the DSOs do, thanks to the persistence of the phosphors and the continuous nature of the "data capture".
I haven't built one of these myself, as I have an old Heathkit plugs-into-your-scope unit, and a 7CT1N plugin for a Tek 'scope
mainframe.
On Wed, 20 Nov 2024 12:27:04 -0800, john larkin wrote:
On Wed, 20 Nov 2024 18:00:34 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 07:40:08 -0800, john larkin wrote:
On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of >>>>>semiconductors and make designing for same much more predictable and >>>>>dependable than relying on spice models and simulation alone. But >>>>>they're typically rare beasts and expensive to come by and boat anchor >>>>>varieties are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent
project,
using the X&Y inputs of a scope as the display. Has anyone here >>>>>attempted this? I'd be interested to know what the main challenges are >>>>>likely to be.
-CD
I've considered it. It would be much more valuable if it traced
capacitances too.
A VNA is best for that. I've been using my big HP one this afternoon to >>>label some random bunches of caps and inductors whose values I couldn't >>>read. Trouble is, there doesn't seem to be much agreement on what >>>frequency to test these devices at. I've heard 100khz, 1Mhz, 10Mhz and >>>100Mhz mentioned from different sources. I'm pretty sure the 100Mhz >>>testing is for RF specified devices only, though. From what I've seen, >>>there's no reliable alternative to testing each batch for oneself, >>>because (certainly with ancient NOS leaded (as in non-SMD) stock) you >>>have no idea what frequency the factory tested them at and different >>>manufacturers in different countries at different times used different >>>methods!
What I want is C-V curves. I guess a VNA can do that with a some bias
tees and various power supplies.
If you only want C/V curves, what's wrong with a plain 'scope and a pulse >generator?
The display should be on a computer and the data archived.
For people such as yourself, certainly. For me as a hobbyist, a CRT is >>>fine.
You have to read the analog screen and write down numbers. Or take a
picture.
It would only be a (slight) issue if I needed to share an image with a
third party. Aside from that, there's nothing I couldn't live with. You're >obviously requiring more than that, though.
I often just set up a breadboard and test parts. Last week I blew out
some power mosfet gates. Some have internal zeners; this one doesn't.
I can kill a MOSFET at 50' just by looking at it (certainly in winter). >>>In fact I shock myself from all the static I build up and it ain't
funny. Having dry skin is great for when I touch HV by accident (happens >>>quite a lot) but the flip side is I accumulate and hold static charge >>>like no one else I know.
Some fets have protective gate zeners. They typically clamp at +-40
volts.
Here in San Francisco, we never get static zapped. High humidity.
So you never need to wear a wrist/earth strap? That's a big plus. I find
them *so* restrictive and irritating when they (invariably) catch on >something.
Most mosfets drain avalanche, but the voltage is never specified, in
fact deliberately hidden. I have to measure that. A good curve tracer >>>> should measure that too.
Currents should go down to picoamps.
The fact that there aren't many curve tracers for sale suggests a
small market.
But a market, though small perhaps, there must be.
Sure. It would be a fun project.
And with thanks to Trump's tariffs, you might even make a few buxx out of
it, too.
On Thu, 21 Nov 2024 00:00:10 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 12:27:04 -0800, john larkin wrote:
On Wed, 20 Nov 2024 18:00:34 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 07:40:08 -0800, john larkin wrote:
On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics >>>>>>of semiconductors and make designing for same much more predictable >>>>>>and dependable than relying on spice models and simulation alone. >>>>>>But they're typically rare beasts and expensive to come by and boat >>>>>>anchor varieties are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent
project,
using the X&Y inputs of a scope as the display. Has anyone here >>>>>>attempted this? I'd be interested to know what the main challenges >>>>>>are likely to be.
-CD
I've considered it. It would be much more valuable if it traced
capacitances too.
A VNA is best for that. I've been using my big HP one this afternoon
to label some random bunches of caps and inductors whose values I >>>>couldn't read. Trouble is, there doesn't seem to be much agreement on >>>>what frequency to test these devices at. I've heard 100khz, 1Mhz,
10Mhz and 100Mhz mentioned from different sources. I'm pretty sure the >>>>100Mhz testing is for RF specified devices only, though. From what
I've seen, there's no reliable alternative to testing each batch for >>>>oneself, because (certainly with ancient NOS leaded (as in non-SMD) >>>>stock) you have no idea what frequency the factory tested them at and >>>>different manufacturers in different countries at different times used >>>>different methods!
What I want is C-V curves. I guess a VNA can do that with a some bias
tees and various power supplies.
If you only want C/V curves, what's wrong with a plain 'scope and a
pulse generator?
How would you do that?
The display should be on a computer and the data archived.
For people such as yourself, certainly. For me as a hobbyist, a CRT is >>>>fine.
You have to read the analog screen and write down numbers. Or take a
picture.
It would only be a (slight) issue if I needed to share an image with a >>third party. Aside from that, there's nothing I couldn't live with.
You're obviously requiring more than that, though.
I often just set up a breadboard and test parts. Last week I blew
out some power mosfet gates. Some have internal zeners; this one
doesn't.
I can kill a MOSFET at 50' just by looking at it (certainly in
winter). In fact I shock myself from all the static I build up and it >>>>ain't funny. Having dry skin is great for when I touch HV by accident >>>>(happens quite a lot) but the flip side is I accumulate and hold
static charge like no one else I know.
Some fets have protective gate zeners. They typically clamp at +-40
volts.
Here in San Francisco, we never get static zapped. High humidity.
So you never need to wear a wrist/earth strap? That's a big plus. I find >>them *so* restrictive and irritating when they (invariably) catch on >>something.
Most mosfets drain avalanche, but the voltage is never specified, in >>>>> fact deliberately hidden. I have to measure that. A good curve
tracer should measure that too.
Currents should go down to picoamps.
The fact that there aren't many curve tracers for sale suggests a
small market.
But a market, though small perhaps, there must be.
Sure. It would be a fun project.
And with thanks to Trump's tariffs, you might even make a few buxx out
of it, too.
Is there going to be tariffs on USB capacitance-measuring curve tracers?
On Wed, 20 Nov 2024 18:14:53 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 08:41:19 -0800, john larkin wrote:
On Wed, 20 Nov 2024 11:02:49 -0500, bitrex <user@example.net> wrote:dp/B0D25RDFDV>
On 11/20/2024 10:58 AM, john larkin wrote:
Meanwhile, in China:
<https://www.amazon.com/Transistor-Tracer-Feature-Graphic-Instrument/
Last chance buy before tariffs kick in and HP re-instates its whole 1987 >>>> catalog to meet the demand for domestically-produced test gear.
Someone seems to still banging out 1970s-style CTs
Barbaric.
You buy one. Give us a review.
Perhaps you should consider developing one for production purposes?
Production semiconductor test is a big business. Automated, not
benchtop instruments with CRT analog displays.
A curve tracer could be a small USB box.
I now that there are some cool "pin driver" ICs that are used in semi
testers and are not available to us civilians.
GPIB ain't modern! It's 50 years old.
Ever read the actual spec? The state diagrams will give you nightmares
for weeks.
On Wed, 20 Nov 2024 16:37:39 -0800, john larkin wrote:
On Thu, 21 Nov 2024 00:00:10 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 12:27:04 -0800, john larkin wrote:
On Wed, 20 Nov 2024 18:00:34 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 07:40:08 -0800, john larkin wrote:
On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics >>>>>>>of semiconductors and make designing for same much more predictable >>>>>>>and dependable than relying on spice models and simulation alone. >>>>>>>But they're typically rare beasts and expensive to come by and boat >>>>>>>anchor varieties are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent
project,
using the X&Y inputs of a scope as the display. Has anyone here >>>>>>>attempted this? I'd be interested to know what the main challenges >>>>>>>are likely to be.
-CD
I've considered it. It would be much more valuable if it traced
capacitances too.
A VNA is best for that. I've been using my big HP one this afternoon >>>>>to label some random bunches of caps and inductors whose values I >>>>>couldn't read. Trouble is, there doesn't seem to be much agreement on >>>>>what frequency to test these devices at. I've heard 100khz, 1Mhz, >>>>>10Mhz and 100Mhz mentioned from different sources. I'm pretty sure the >>>>>100Mhz testing is for RF specified devices only, though. From what >>>>>I've seen, there's no reliable alternative to testing each batch for >>>>>oneself, because (certainly with ancient NOS leaded (as in non-SMD) >>>>>stock) you have no idea what frequency the factory tested them at and >>>>>different manufacturers in different countries at different times used >>>>>different methods!
What I want is C-V curves. I guess a VNA can do that with a some bias
tees and various power supplies.
If you only want C/V curves, what's wrong with a plain 'scope and a
pulse generator?
How would you do that?
Ah! Well, I obviously mis-read your earlier statement. My bad, soz.
The display should be on a computer and the data archived.
For people such as yourself, certainly. For me as a hobbyist, a CRT is >>>>>fine.
You have to read the analog screen and write down numbers. Or take a
picture.
It would only be a (slight) issue if I needed to share an image with a >>>third party. Aside from that, there's nothing I couldn't live with. >>>You're obviously requiring more than that, though.
I often just set up a breadboard and test parts. Last week I blew
out some power mosfet gates. Some have internal zeners; this one
doesn't.
I can kill a MOSFET at 50' just by looking at it (certainly in >>>>>winter). In fact I shock myself from all the static I build up and it >>>>>ain't funny. Having dry skin is great for when I touch HV by accident >>>>>(happens quite a lot) but the flip side is I accumulate and hold >>>>>static charge like no one else I know.
Some fets have protective gate zeners. They typically clamp at +-40
volts.
Here in San Francisco, we never get static zapped. High humidity.
So you never need to wear a wrist/earth strap? That's a big plus. I find >>>them *so* restrictive and irritating when they (invariably) catch on >>>something.
Most mosfets drain avalanche, but the voltage is never specified, in >>>>>> fact deliberately hidden. I have to measure that. A good curve
tracer should measure that too.
Currents should go down to picoamps.
The fact that there aren't many curve tracers for sale suggests a
small market.
But a market, though small perhaps, there must be.
Sure. It would be a fun project.
And with thanks to Trump's tariffs, you might even make a few buxx out
of it, too.
Is there going to be tariffs on USB capacitance-measuring curve tracers?
Not specifically, but I imagine Trump will want tariffs on Chinese imports
in general, which should give some breathing space profit-wise to US >manufacturers.
I have to say I do admire Trump's job creation ideas, which should produce >solid results, as opposed to old Joe's approach of destroying US jobs, >seemingly on purpose. I say old Joe's approach, but what I really mean is
the approach of the Globalists who tell him and his ilk what to do.
On 2024-11-20 21:30, john larkin wrote:GPIB was the PLPS2005 (https://www.artisantg.com/info/Muetta_PLPS2005_Manual.pdf).
GPIB ain't modern! It's 50 years old.
Ever read the actual spec? The state diagrams will give you nightmares
for weeks.
Reading the spec and studying the state diagrams was a great learning experience. No nightmares whatsoever.
I designed lots of GPIB = HPIB = IEEE-488 interfaces for existing and new equipment, first starting with TTL, then CMOS, then LSI chips, then MCU bit-banging, and finally using the NI (National Instruments) chips together with an MCU. Last design with
Made lots of money on those designs. Also discovered a bug in the MC68488 chip from Motorola, they acknowledged it later (all communication by telex in those days).
Arie
On Thu, 21 Nov 2024 12:02:28 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 16:37:39 -0800, john larkin wrote:
On Thu, 21 Nov 2024 00:00:10 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 12:27:04 -0800, john larkin wrote:
On Wed, 20 Nov 2024 18:00:34 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 07:40:08 -0800, john larkin wrote:
On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics >>>>>>>>of semiconductors and make designing for same much more >>>>>>>>predictable and dependable than relying on spice models and >>>>>>>>simulation alone. But they're typically rare beasts and expensive >>>>>>>>to come by and boat anchor varieties are seriously heavy and >>>>>>>>bulky.
I think therefore that a curve tracer would make an excellent
project,
using the X&Y inputs of a scope as the display. Has anyone here >>>>>>>>attempted this? I'd be interested to know what the main challenges >>>>>>>>are likely to be.
-CD
I've considered it. It would be much more valuable if it traced
capacitances too.
A VNA is best for that. I've been using my big HP one this afternoon >>>>>>to label some random bunches of caps and inductors whose values I >>>>>>couldn't read. Trouble is, there doesn't seem to be much agreement >>>>>>on what frequency to test these devices at. I've heard 100khz, 1Mhz, >>>>>>10Mhz and 100Mhz mentioned from different sources. I'm pretty sure >>>>>>the 100Mhz testing is for RF specified devices only, though. From >>>>>>what I've seen, there's no reliable alternative to testing each >>>>>>batch for oneself, because (certainly with ancient NOS leaded (as in >>>>>>non-SMD) stock) you have no idea what frequency the factory tested >>>>>>them at and different manufacturers in different countries at >>>>>>different times used different methods!
What I want is C-V curves. I guess a VNA can do that with a some
bias tees and various power supplies.
If you only want C/V curves, what's wrong with a plain 'scope and a >>>>pulse generator?
How would you do that?
Ah! Well, I obviously mis-read your earlier statement. My bad, soz.
The display should be on a computer and the data archived.
For people such as yourself, certainly. For me as a hobbyist, a CRT >>>>>>is fine.
You have to read the analog screen and write down numbers. Or take a >>>>> picture.
It would only be a (slight) issue if I needed to share an image with a >>>>third party. Aside from that, there's nothing I couldn't live with. >>>>You're obviously requiring more than that, though.
I often just set up a breadboard and test parts. Last week I blew >>>>>>> out some power mosfet gates. Some have internal zeners; this one >>>>>>> doesn't.
I can kill a MOSFET at 50' just by looking at it (certainly in >>>>>>winter). In fact I shock myself from all the static I build up and >>>>>>it ain't funny. Having dry skin is great for when I touch HV by >>>>>>accident (happens quite a lot) but the flip side is I accumulate and >>>>>>hold static charge like no one else I know.
Some fets have protective gate zeners. They typically clamp at +-40
volts.
Here in San Francisco, we never get static zapped. High humidity.
So you never need to wear a wrist/earth strap? That's a big plus. I >>>>find them *so* restrictive and irritating when they (invariably) catch >>>>on something.
Most mosfets drain avalanche, but the voltage is never specified, >>>>>>> in fact deliberately hidden. I have to measure that. A good curve >>>>>>> tracer should measure that too.
Currents should go down to picoamps.
The fact that there aren't many curve tracers for sale suggests a >>>>>>> small market.
But a market, though small perhaps, there must be.
Sure. It would be a fun project.
And with thanks to Trump's tariffs, you might even make a few buxx out >>>>of it, too.
Is there going to be tariffs on USB capacitance-measuring curve
tracers?
Not specifically, but I imagine Trump will want tariffs on Chinese
imports in general, which should give some breathing space profit-wise
to US manufacturers.
I have to say I do admire Trump's job creation ideas, which should
produce solid results, as opposed to old Joe's approach of destroying US >>jobs, seemingly on purpose. I say old Joe's approach, but what I really >>mean is the approach of the Globalists who tell him and his ilk what to
do.
We should stop paying the Chinese for the shipping costs of cheap junk,
for starters.
On Thu, 21 Nov 2024 08:03:00 -0800, john larkin wrote:
On Thu, 21 Nov 2024 12:02:28 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 16:37:39 -0800, john larkin wrote:
On Thu, 21 Nov 2024 00:00:10 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 12:27:04 -0800, john larkin wrote:
On Wed, 20 Nov 2024 18:00:34 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 07:40:08 -0800, john larkin wrote:
On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics >>>>>>>>>of semiconductors and make designing for same much more >>>>>>>>>predictable and dependable than relying on spice models and >>>>>>>>>simulation alone. But they're typically rare beasts and expensive >>>>>>>>>to come by and boat anchor varieties are seriously heavy and >>>>>>>>>bulky.
I think therefore that a curve tracer would make an excellent >>>>>>>>> project,
using the X&Y inputs of a scope as the display. Has anyone here >>>>>>>>>attempted this? I'd be interested to know what the main challenges >>>>>>>>>are likely to be.
-CD
I've considered it. It would be much more valuable if it traced >>>>>>>> capacitances too.
A VNA is best for that. I've been using my big HP one this afternoon >>>>>>>to label some random bunches of caps and inductors whose values I >>>>>>>couldn't read. Trouble is, there doesn't seem to be much agreement >>>>>>>on what frequency to test these devices at. I've heard 100khz, 1Mhz, >>>>>>>10Mhz and 100Mhz mentioned from different sources. I'm pretty sure >>>>>>>the 100Mhz testing is for RF specified devices only, though. From >>>>>>>what I've seen, there's no reliable alternative to testing each >>>>>>>batch for oneself, because (certainly with ancient NOS leaded (as in >>>>>>>non-SMD) stock) you have no idea what frequency the factory tested >>>>>>>them at and different manufacturers in different countries at >>>>>>>different times used different methods!
What I want is C-V curves. I guess a VNA can do that with a some
bias tees and various power supplies.
If you only want C/V curves, what's wrong with a plain 'scope and a >>>>>pulse generator?
How would you do that?
Ah! Well, I obviously mis-read your earlier statement. My bad, soz.
The display should be on a computer and the data archived.
For people such as yourself, certainly. For me as a hobbyist, a CRT >>>>>>>is fine.
You have to read the analog screen and write down numbers. Or take a >>>>>> picture.
It would only be a (slight) issue if I needed to share an image with a >>>>>third party. Aside from that, there's nothing I couldn't live with. >>>>>You're obviously requiring more than that, though.
I often just set up a breadboard and test parts. Last week I blew >>>>>>>> out some power mosfet gates. Some have internal zeners; this one >>>>>>>> doesn't.
I can kill a MOSFET at 50' just by looking at it (certainly in >>>>>>>winter). In fact I shock myself from all the static I build up and >>>>>>>it ain't funny. Having dry skin is great for when I touch HV by >>>>>>>accident (happens quite a lot) but the flip side is I accumulate and >>>>>>>hold static charge like no one else I know.
Some fets have protective gate zeners. They typically clamp at +-40 >>>>>> volts.
Here in San Francisco, we never get static zapped. High humidity.
So you never need to wear a wrist/earth strap? That's a big plus. I >>>>>find them *so* restrictive and irritating when they (invariably) catch >>>>>on something.
Most mosfets drain avalanche, but the voltage is never specified, >>>>>>>> in fact deliberately hidden. I have to measure that. A good curve >>>>>>>> tracer should measure that too.
Currents should go down to picoamps.
The fact that there aren't many curve tracers for sale suggests a >>>>>>>> small market.
But a market, though small perhaps, there must be.
Sure. It would be a fun project.
And with thanks to Trump's tariffs, you might even make a few buxx out >>>>>of it, too.
Is there going to be tariffs on USB capacitance-measuring curve
tracers?
Not specifically, but I imagine Trump will want tariffs on Chinese >>>imports in general, which should give some breathing space profit-wise
to US manufacturers.
I have to say I do admire Trump's job creation ideas, which should >>>produce solid results, as opposed to old Joe's approach of destroying US >>>jobs, seemingly on purpose. I say old Joe's approach, but what I really >>>mean is the approach of the Globalists who tell him and his ilk what to >>>do.
We should stop paying the Chinese for the shipping costs of cheap junk,
for starters.
The US does that too?? Wow. I thought that was just a European thing.
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of semiconductors and make designing for same much more predictable and dependable than relying on spice models and simulation alone. But they're typically rare beasts and expensive to come by and boat anchor varieties
are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project, using the X&Y inputs of a scope as the display. Has anyone here attempted this? I'd be interested to know what the main challenges are likely to be.
-CD
On Wed, 20 Nov 2024 10:43:34 -0500, bitrex <user@example.net> wrote:
On 11/20/2024 6:32 AM, Cursitor Doom wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of
semiconductors and make designing for same much more predictable and
dependable than relying on spice models and simulation alone. But they're >>> typically rare beasts and expensive to come by and boat anchor varieties >>> are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project, >>> using the X&Y inputs of a scope as the display. Has anyone here attempted >>> this? I'd be interested to know what the main challenges are likely to be. >>>
-CD
A bit more modern way to do this is get one of those HP data acquisition
units like a 34970A with a multiplexer card, and a multi-output PSU that
can both be controlled over GP-IB
GPIB ain't modern! It's 50 years old.
Ever read the actual spec? The state diagrams will give you nightmares
for weeks.
On 11/20/24 11:32, Cursitor Doom wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of
semiconductors and make designing for same much more predictable and
dependable than relying on spice models and simulation alone. But they're
typically rare beasts and expensive to come by and boat anchor varieties
are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project,
using the X&Y inputs of a scope as the display. Has anyone here attempted
this? I'd be interested to know what the main challenges are likely to be. >>
-CD
It's not too difficult to build a low power ct. We built one
in school decades ago, using a diode pump and clock, to generate
the stair step base drive. IIrc, we used half wave rectified
ac for the collector sweep.
Not so easy to build an accurate system, especially for testing
power devices, which typically need high voltage and current.
Here, an old Fairchild 6200B, none working from Ebay, gets
regular use, both go / no go and for matching devices. That dates
back to the late 1960s, and uses a four stage binary counter,
with 1,2,4,8 resistor network d to a, to generate the stairstep.
A small variac drives the collector sweep.
Chris
On Wed, 20 Nov 2024 16:37:39 -0800, john larkin wrote:
On Thu, 21 Nov 2024 00:00:10 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 12:27:04 -0800, john larkin wrote:
On Wed, 20 Nov 2024 18:00:34 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 07:40:08 -0800, john larkin wrote:
On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
Is there going to be tariffs on USB capacitance-measuring curve tracers?
Not specifically, but I imagine Trump will want tariffs on Chinese imports
in general, which should give some breathing space profit-wise to US manufacturers.
I have to say I do admire Trump's job creation ideas, which should produce solid results,
as opposed to old Joe's approach of destroying US jobs,
seemingly on purpose. I say old Joe's approach, but what I really mean is
the approach of the Globalists who tell him and his ilk what to do.
On Thu, 21 Nov 2024 23:35:13 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:
On Thu, 21 Nov 2024 08:03:00 -0800, john larkin wrote:
On Thu, 21 Nov 2024 12:02:28 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 16:37:39 -0800, john larkin wrote:
On Thu, 21 Nov 2024 00:00:10 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 12:27:04 -0800, john larkin wrote:
On Wed, 20 Nov 2024 18:00:34 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 07:40:08 -0800, john larkin wrote:
On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic >>>>>>>>>>characteristics of semiconductors and make designing for same >>>>>>>>>>much more predictable and dependable than relying on spice >>>>>>>>>>models and simulation alone. But they're typically rare beasts >>>>>>>>>>and expensive to come by and boat anchor varieties are seriously >>>>>>>>>>heavy and bulky.
I think therefore that a curve tracer would make an excellent >>>>>>>>>> project,
using the X&Y inputs of a scope as the display. Has anyone here >>>>>>>>>>attempted this? I'd be interested to know what the main >>>>>>>>>>challenges are likely to be.
-CD
I've considered it. It would be much more valuable if it traced >>>>>>>>> capacitances too.
A VNA is best for that. I've been using my big HP one this >>>>>>>>afternoon to label some random bunches of caps and inductors whose >>>>>>>>values I couldn't read. Trouble is, there doesn't seem to be much >>>>>>>>agreement on what frequency to test these devices at. I've heard >>>>>>>>100khz, 1Mhz,
10Mhz and 100Mhz mentioned from different sources. I'm pretty sure >>>>>>>>the 100Mhz testing is for RF specified devices only, though. From >>>>>>>>what I've seen, there's no reliable alternative to testing each >>>>>>>>batch for oneself, because (certainly with ancient NOS leaded (as >>>>>>>>in non-SMD) stock) you have no idea what frequency the factory >>>>>>>>tested them at and different manufacturers in different countries >>>>>>>>at different times used different methods!
What I want is C-V curves. I guess a VNA can do that with a some >>>>>>> bias tees and various power supplies.
If you only want C/V curves, what's wrong with a plain 'scope and a >>>>>>pulse generator?
How would you do that?
Ah! Well, I obviously mis-read your earlier statement. My bad, soz.
The display should be on a computer and the data archived.
For people such as yourself, certainly. For me as a hobbyist, a >>>>>>>>CRT is fine.
You have to read the analog screen and write down numbers. Or take >>>>>>> a picture.
It would only be a (slight) issue if I needed to share an image with >>>>>>a third party. Aside from that, there's nothing I couldn't live >>>>>>with. You're obviously requiring more than that, though.
So you never need to wear a wrist/earth strap? That's a big plus. I >>>>>>find them *so* restrictive and irritating when they (invariably) >>>>>>catch on something.I often just set up a breadboard and test parts. Last week I >>>>>>>>> blew out some power mosfet gates. Some have internal zeners; >>>>>>>>> this one doesn't.
I can kill a MOSFET at 50' just by looking at it (certainly in >>>>>>>>winter). In fact I shock myself from all the static I build up and >>>>>>>>it ain't funny. Having dry skin is great for when I touch HV by >>>>>>>>accident (happens quite a lot) but the flip side is I accumulate >>>>>>>>and hold static charge like no one else I know.
Some fets have protective gate zeners. They typically clamp at
+-40 volts.
Here in San Francisco, we never get static zapped. High humidity. >>>>>>
Most mosfets drain avalanche, but the voltage is never
specified, in fact deliberately hidden. I have to measure that. >>>>>>>>> A good curve tracer should measure that too.
Currents should go down to picoamps.
The fact that there aren't many curve tracers for sale suggests >>>>>>>>> a small market.
But a market, though small perhaps, there must be.
Sure. It would be a fun project.
And with thanks to Trump's tariffs, you might even make a few buxx >>>>>>out of it, too.
Is there going to be tariffs on USB capacitance-measuring curve
tracers?
Not specifically, but I imagine Trump will want tariffs on Chinese >>>>imports in general, which should give some breathing space profit-wise >>>>to US manufacturers.
I have to say I do admire Trump's job creation ideas, which should >>>>produce solid results, as opposed to old Joe's approach of destroying >>>>US jobs, seemingly on purpose. I say old Joe's approach, but what I >>>>really mean is the approach of the Globalists who tell him and his ilk >>>>what to do.
We should stop paying the Chinese for the shipping costs of cheap
junk,
for starters.
The US does that too?? Wow. I thought that was just a European thing.
The Chinese are a "disadvantaged country" per the International Postal
Union.
They will ship a cheap ebay thing here for free. It would cost me a
bundle to ship it back.
On Wed, 20 Nov 2024 11:02:49 -0500, bitrex wrote:
On 11/20/2024 10:58 AM, john larkin wrote:dp/B0D25RDFDV>
Meanwhile, in China:
<https://www.amazon.com/Transistor-Tracer-Feature-Graphic-Instrument/
Last chance buy before tariffs kick in and HP re-instates its whole 1987
Someone seems to still banging out 1970s-style CTs
Barbaric.
catalog to meet the demand for domestically-produced test gear.
Yes, Trump may well be throwing them a lifeline. HP products might once
again be craned and fork-lifted into RF developers' labs across the
nation!
I can't see any price listed for the Chinese CT for some reason. Any idea
how much it is?
On Thu, 21 Nov 2024 15:43:21 -0800, john larkin wrote:
On Thu, 21 Nov 2024 23:35:13 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
On Thu, 21 Nov 2024 08:03:00 -0800, john larkin wrote:
On Thu, 21 Nov 2024 12:02:28 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 16:37:39 -0800, john larkin wrote:
On Thu, 21 Nov 2024 00:00:10 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 12:27:04 -0800, john larkin wrote:
On Wed, 20 Nov 2024 18:00:34 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
On Wed, 20 Nov 2024 07:40:08 -0800, john larkin wrote:
On Wed, 20 Nov 2024 11:32:32 -0000 (UTC), Cursitor Doom
<cd999666@notformail.com> wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic
characteristics of semiconductors and make designing for same >>>>>>>>>>> much more predictable and dependable than relying on spice >>>>>>>>>>> models and simulation alone. But they're typically rare beasts >>>>>>>>>>> and expensive to come by and boat anchor varieties are seriously >>>>>>>>>>> heavy and bulky.
I think therefore that a curve tracer would make an excellent >>>>>>>>>>> project,
using the X&Y inputs of a scope as the display. Has anyone here >>>>>>>>>>> attempted this? I'd be interested to know what the main
challenges are likely to be.
-CD
I've considered it. It would be much more valuable if it traced >>>>>>>>>> capacitances too.
A VNA is best for that. I've been using my big HP one this
afternoon to label some random bunches of caps and inductors whose >>>>>>>>> values I couldn't read. Trouble is, there doesn't seem to be much >>>>>>>>> agreement on what frequency to test these devices at. I've heard >>>>>>>>> 100khz, 1Mhz,
10Mhz and 100Mhz mentioned from different sources. I'm pretty sure >>>>>>>>> the 100Mhz testing is for RF specified devices only, though. From >>>>>>>>> what I've seen, there's no reliable alternative to testing each >>>>>>>>> batch for oneself, because (certainly with ancient NOS leaded (as >>>>>>>>> in non-SMD) stock) you have no idea what frequency the factory >>>>>>>>> tested them at and different manufacturers in different countries >>>>>>>>> at different times used different methods!
What I want is C-V curves. I guess a VNA can do that with a some >>>>>>>> bias tees and various power supplies.
If you only want C/V curves, what's wrong with a plain 'scope and a >>>>>>> pulse generator?
How would you do that?
Ah! Well, I obviously mis-read your earlier statement. My bad, soz.
The display should be on a computer and the data archived.
For people such as yourself, certainly. For me as a hobbyist, a >>>>>>>>> CRT is fine.
You have to read the analog screen and write down numbers. Or take >>>>>>>> a picture.
It would only be a (slight) issue if I needed to share an image with >>>>>>> a third party. Aside from that, there's nothing I couldn't live
with. You're obviously requiring more than that, though.
So you never need to wear a wrist/earth strap? That's a big plus. I >>>>>>> find them *so* restrictive and irritating when they (invariably) >>>>>>> catch on something.I often just set up a breadboard and test parts. Last week I >>>>>>>>>> blew out some power mosfet gates. Some have internal zeners; >>>>>>>>>> this one doesn't.
I can kill a MOSFET at 50' just by looking at it (certainly in >>>>>>>>> winter). In fact I shock myself from all the static I build up and >>>>>>>>> it ain't funny. Having dry skin is great for when I touch HV by >>>>>>>>> accident (happens quite a lot) but the flip side is I accumulate >>>>>>>>> and hold static charge like no one else I know.
Some fets have protective gate zeners. They typically clamp at >>>>>>>> +-40 volts.
Here in San Francisco, we never get static zapped. High humidity. >>>>>>>
Most mosfets drain avalanche, but the voltage is never
specified, in fact deliberately hidden. I have to measure that. >>>>>>>>>> A good curve tracer should measure that too.
Currents should go down to picoamps.
The fact that there aren't many curve tracers for sale suggests >>>>>>>>>> a small market.
But a market, though small perhaps, there must be.
Sure. It would be a fun project.
And with thanks to Trump's tariffs, you might even make a few buxx >>>>>>> out of it, too.
Is there going to be tariffs on USB capacitance-measuring curve
tracers?
Not specifically, but I imagine Trump will want tariffs on Chinese
imports in general, which should give some breathing space profit-wise >>>>> to US manufacturers.
I have to say I do admire Trump's job creation ideas, which should
produce solid results, as opposed to old Joe's approach of destroying >>>>> US jobs, seemingly on purpose. I say old Joe's approach, but what I
really mean is the approach of the Globalists who tell him and his ilk >>>>> what to do.
We should stop paying the Chinese for the shipping costs of cheap
junk,
for starters.
The US does that too?? Wow. I thought that was just a European thing.
The Chinese are a "disadvantaged country" per the International Postal
Union.
That needs updating!
They will ship a cheap ebay thing here for free. It would cost me a
bundle to ship it back.
Same here. Function generator arrived today direct from China and I didn't have to pay a penny in sales tax for it. No duties whatsoever. Express postage was free, too. The treasuries of Europe must be losing untold tens
of billions in taxes due to this. And yet everyone has to pay sales tax on domestically-produced goods! It's madness on steroids. They'll probably
claim it would cost more to collect the tax than the revenue doing so
would generate, but that's indefensible BS plain and simple.
On Wed, 20 Nov 2024 10:43:34 -0500, bitrex <user@example.net> wrote:
On 11/20/2024 6:32 AM, Cursitor Doom wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of
semiconductors and make designing for same much more predictable and
dependable than relying on spice models and simulation alone. But they're >>> typically rare beasts and expensive to come by and boat anchor varieties >>> are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project, >>> using the X&Y inputs of a scope as the display. Has anyone here attempted >>> this? I'd be interested to know what the main challenges are likely to be. >>>
-CD
A bit more modern way to do this is get one of those HP data acquisition >>units like a 34970A with a multiplexer card, and a multi-output PSU that >>can both be controlled over GP-IB
GPIB ain't modern! It's 50 years old.
Ever read the actual spec? The state diagrams will give you nightmares
for weeks.
In article <fhhsjj5ptu03hoo99g1ki6s85ffq98t2gb@4ax.com>,
john larkin <jl@glen--canyon.com> wrote:
On Wed, 20 Nov 2024 10:43:34 -0500, bitrex <user@example.net> wrote:
On 11/20/2024 6:32 AM, Cursitor Doom wrote:
Gentlemen,
Curve tracers reveal useful info about the dynamic characteristics of
semiconductors and make designing for same much more predictable and
dependable than relying on spice models and simulation alone. But they're >>>> typically rare beasts and expensive to come by and boat anchor varieties >>>> are seriously heavy and bulky.
I think therefore that a curve tracer would make an excellent project, >>>> using the X&Y inputs of a scope as the display. Has anyone here attempted >>>> this? I'd be interested to know what the main challenges are likely to be. >>>>
-CD
A bit more modern way to do this is get one of those HP data acquisition >>> units like a 34970A with a multiplexer card, and a multi-output PSU that >>> can both be controlled over GP-IB
GPIB ain't modern! It's 50 years old.
Ever read the actual spec? The state diagrams will give you nightmares
for weeks.
The Dutch Forth user group has a HP plotter 7470A, handboek, spare pens.
The idea is to have hooked it up to a computer. Apparently not so easy.
Any bids on a double 8" floppy HP9895A?
Groetjes Albert
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