J
John S
Guest
On 3/7/2023 9:45 AM, John Larkin wrote:
Exactly!!
--
Dogs make me happy. Humans make my head hurt.
Exactly!!
--
Dogs make me happy. Humans make my head hurt.
P
Phil Hobbs
Guest
On 2023-03-07 18:21, John S wrote:
You can run the tolerances looser if you like. Occasionally it saves
time. A custom dialog box giving some guidance on how to do that would
be a nice feature.
I\'ve occasionally needed to do that, e.g. when doing photoreceiver sims
at the 1-nA photocurrent level, you sort of need to tighten the abstol
settings. I\'m no SPICE guru, though.
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
You can run the tolerances looser if you like. Occasionally it saves
time. A custom dialog box giving some guidance on how to do that would
be a nice feature.
I\'ve occasionally needed to do that, e.g. when doing photoreceiver sims
at the 1-nA photocurrent level, you sort of need to tighten the abstol
settings. I\'m no SPICE guru, though.
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
J
John Larkin
Guest
On Tue, 7 Mar 2023 20:05:16 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
..opt abstol=2nA
..opt chgtol=10pC
..opt trtol=5
..opt reltol=0.002
..opt method=trap
seems to help slow ones. I just slop things up until the sim doesn\'t
look believable, and back off some.
I\'ve done sims that take an hour to run a few milliseconds. Feedback
that slow doesn\'t train your instincts.
<pcdhSpamMeSenseless@electrooptical.net> wrote:
..opt abstol=2nA
..opt chgtol=10pC
..opt trtol=5
..opt reltol=0.002
..opt method=trap
seems to help slow ones. I just slop things up until the sim doesn\'t
look believable, and back off some.
I\'ve done sims that take an hour to run a few milliseconds. Feedback
that slow doesn\'t train your instincts.
P
Phil Hobbs
Guest
On 2023-03-07 20:29, John Larkin wrote:
A bunch of my stuff wouldn\'t budge off the peg with those settings.
If you already know what it should look like, why simulate?
Using universal opamps and VCVSes helps sometimes.
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
A bunch of my stuff wouldn\'t budge off the peg with those settings.
If you already know what it should look like, why simulate?
Using universal opamps and VCVSes helps sometimes.
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
J
John Larkin
Guest
On Tue, 7 Mar 2023 22:15:32 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
To play with ideas fast day or night, and to get the parts values
right. It\'s often easier to sim, say, a voltage divider than to do a
lot of math.
I\'ve invented some cool but improbable circuits by fiddling in Spice.
My ac/dc programmable dummy load was an unexpected accident and is now
a product.
Doing the .opt tricks is safe if you are careful, which isn\'t hard.
Run a slow sim, note a few points, booger the sim until it changes
much, back off. I suppose that the options affect the internals of
imported models, so all you can do is try.
I most always use one of the universal opamps, because LT Spice seldom
models mine, and it\'s too hard to research their list to find one
that\'s close to what I intend to use. The bv block can really simplify
and speed up a sim, and is an easy way to compute things to plot.
<pcdhSpamMeSenseless@electrooptical.net> wrote:
To play with ideas fast day or night, and to get the parts values
right. It\'s often easier to sim, say, a voltage divider than to do a
lot of math.
I\'ve invented some cool but improbable circuits by fiddling in Spice.
My ac/dc programmable dummy load was an unexpected accident and is now
a product.
Doing the .opt tricks is safe if you are careful, which isn\'t hard.
Run a slow sim, note a few points, booger the sim until it changes
much, back off. I suppose that the options affect the internals of
imported models, so all you can do is try.
I most always use one of the universal opamps, because LT Spice seldom
models mine, and it\'s too hard to research their list to find one
that\'s close to what I intend to use. The bv block can really simplify
and speed up a sim, and is an easy way to compute things to plot.
P
Phil Hobbs
Guest
On 2023-03-08 10:47, John Larkin wrote:
I\'ve been known to dork frequency compensation that way too, and to look
at tolerances for filters.
The last thing I designed by poking at in SPICE was a collapsible BJT
cascode, where the top transistor had to take a bunch of voltage. When
the bottom transistor turned on, the top one saturated, pulling down its
relatively high-Z base bias string, so the low level was just the sum of
the V_CE(sat)s.
I knew that part would work, but needed to figure out what the turn-off
transient would look like. The answer was, \"Nothing too pretty, but
good enough for government work.\" It didn\'t look like the top
transistor would reliably come out of saturation fast enough to avoid
blowing up the bottom one, but a zener on its base solved that.
Our ideas of \"a lot of math\" are a bit different, but doing that is no
worse than using a calculator.
(I try to keep in practice doing
mental arithmetic, because it makes me a much better troubleshooter.)
I\'ve done that in a pinch. I normally don\'t simulate big wodges of
circuitry, so it doesn\'t come up much.
Once in a great while I\'ve needed to simulate the start-up or ring-down
of an oscillator, which can take forever, but you do more of those, I
expect.
Op amp models are such random-number generators anyway.... Once in
awhile you get one that models asymmetrical slewing, but not very often.
A depressing number even get the supply current all cattywampus. Even
UniversalOpamp2 gets that right!
Yup. I usually compute efficiencies that way, for instance.
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
I\'ve been known to dork frequency compensation that way too, and to look
at tolerances for filters.
The last thing I designed by poking at in SPICE was a collapsible BJT
cascode, where the top transistor had to take a bunch of voltage. When
the bottom transistor turned on, the top one saturated, pulling down its
relatively high-Z base bias string, so the low level was just the sum of
the V_CE(sat)s.
I knew that part would work, but needed to figure out what the turn-off
transient would look like. The answer was, \"Nothing too pretty, but
good enough for government work.\" It didn\'t look like the top
transistor would reliably come out of saturation fast enough to avoid
blowing up the bottom one, but a zener on its base solved that.
Our ideas of \"a lot of math\" are a bit different, but doing that is no
worse than using a calculator.
(I try to keep in practice doingmental arithmetic, because it makes me a much better troubleshooter.)
I\'ve done that in a pinch. I normally don\'t simulate big wodges of
circuitry, so it doesn\'t come up much.
Once in a great while I\'ve needed to simulate the start-up or ring-down
of an oscillator, which can take forever, but you do more of those, I
expect.
Op amp models are such random-number generators anyway.... Once in
awhile you get one that models asymmetrical slewing, but not very often.
A depressing number even get the supply current all cattywampus. Even
UniversalOpamp2 gets that right!
Yup. I usually compute efficiencies that way, for instance.
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
J
John Larkin
Guest
On Wed, 8 Mar 2023 11:23:50 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
Right. Any interesting control loop is nonlinear.
A non-trivial voltage divider, with more than two resistors, can be a
pain to work out with a calculator, especially using the parts you
already have in stock.
And Spice sims, with comments, are easy to save in a design notes
folder.
I do a lot of mental arithmetic, but it\'s analog computing, guesswork
and not manipulating digits in my head. I usually come in around 5 or
10% accuracy, which is handy enough in most cases. Doing this at a
whiteboard, in a meeting, seems to annoy some people. This used to be
called \"Lightning Empiricism\"; see Williams 1991.
Thank goodness for that! I sometimes use the supply rails as the
outputs of an opamp, to drive big power booster fets for example, and
I need that to be right, statically and dynamically. As I noted
recently, I found one ADI opamp that pulls 1e17 amps on V+.
Some will *output* free kilowatts from their power rails.
<pcdhSpamMeSenseless@electrooptical.net> wrote:
Right. Any interesting control loop is nonlinear.
The last thing I designed by poking at in SPICE was a collapsible BJT
cascode, where the top transistor had to take a bunch of voltage. When
the bottom transistor turned on, the top one saturated, pulling down its
relatively high-Z base bias string, so the low level was just the sum of
the V_CE(sat)s.
I knew that part would work, but needed to figure out what the turn-off
transient would look like. The answer was, \"Nothing too pretty, but
good enough for government work.\" It didn\'t look like the top
transistor would reliably come out of saturation fast enough to avoid
blowing up the bottom one, but a zener on its base solved that.
It\'s often easier to sim, say, a voltage divider than to do a lot of
math.
Our ideas of \"a lot of math\" are a bit different, but doing that is no
worse than using a calculator.
mental arithmetic, because it makes me a much better troubleshooter.)
A non-trivial voltage divider, with more than two resistors, can be a
pain to work out with a calculator, especially using the parts you
already have in stock.
And Spice sims, with comments, are easy to save in a design notes
folder.
I do a lot of mental arithmetic, but it\'s analog computing, guesswork
and not manipulating digits in my head. I usually come in around 5 or
10% accuracy, which is handy enough in most cases. Doing this at a
whiteboard, in a meeting, seems to annoy some people. This used to be
called \"Lightning Empiricism\"; see Williams 1991.
Thank goodness for that! I sometimes use the supply rails as the
outputs of an opamp, to drive big power booster fets for example, and
I need that to be right, statically and dynamically. As I noted
recently, I found one ADI opamp that pulls 1e17 amps on V+.
Some will *output* free kilowatts from their power rails.
P
Phil Hobbs
Guest
On 2023-03-08 12:59, John Larkin wrote:
Yup. They go in our git repos too (one repo per project).
I like to make it a game. It\'s memory more than anything--in 1 Hz, 3 uA
of photocurrent has 1 pA shot noise; for Johnson, 60.4 ohms has 1 nV and
16k has 1 pA.
Going up and down decibels is fun too: 1 dB is 12% voltage and 25%
power, pi = 10 dB (voltage), and so 2 pi = 16 dB. A noise contribution
that\'s 6 dB down raises the floor by 1 dB, and it goes down linearly (in
dB) for lower noise.
Whiteboards are great fun, when combined with an interesting problem and
one-to-three smart and good-natured colleagues. (And possibly a pitcher
of beer.)
It\'s a good trick, for sure, but not all amps like it. Old-timey
\'single supply\' amps often have very very poor PSR on V-, because of
course the designer expects you to ground it, duh.
Since CMR is input-referred, you can get _voltage gain_ between V- and
the output, which makes life very exciting. UniversalOpamp2 will _not_
model that correctly.
Very non-green, for sure.
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
On Wed, 8 Mar 2023 11:23:50 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:
On 2023-03-08 10:47, John Larkin wrote:
On Tue, 7 Mar 2023 22:15:32 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:
A bunch of my stuff wouldn\'t budge off the peg with those
settings. If you already know what it should look like, why
simulate?
To play with ideas fast day or night, and to get the parts
values right.
I\'ve been known to dork frequency compensation that way too, and to
look at tolerances for filters.
Right. Any interesting control loop is nonlinear.
The last thing I designed by poking at in SPICE was a collapsible
BJT cascode, where the top transistor had to take a bunch of
voltage. When the bottom transistor turned on, the top one
saturated, pulling down its relatively high-Z base bias string, so
the low level was just the sum of the V_CE(sat)s.
I knew that part would work, but needed to figure out what the
turn-off transient would look like. The answer was, \"Nothing too
pretty, but good enough for government work.\" It didn\'t look like
the top transistor would reliably come out of saturation fast
enough to avoid blowing up the bottom one, but a zener on its base
solved that.
It\'s often easier to sim, say, a voltage divider than to do a lot
of math.
Our ideas of \"a lot of math\" are a bit different, but doing that is
no worse than using a calculator.
doing mental arithmetic, because it makes me a much better
troubleshooter.)
A non-trivial voltage divider, with more than two resistors, can be
a pain to work out with a calculator, especially using the parts you
already have in stock.
And Spice sims, with comments, are easy to save in a design notes
folder.
Yup. They go in our git repos too (one repo per project).
I like to make it a game. It\'s memory more than anything--in 1 Hz, 3 uA
of photocurrent has 1 pA shot noise; for Johnson, 60.4 ohms has 1 nV and
16k has 1 pA.
Going up and down decibels is fun too: 1 dB is 12% voltage and 25%
power, pi = 10 dB (voltage), and so 2 pi = 16 dB. A noise contribution
that\'s 6 dB down raises the floor by 1 dB, and it goes down linearly (in
dB) for lower noise.
Whiteboards are great fun, when combined with an interesting problem and
one-to-three smart and good-natured colleagues. (And possibly a pitcher
of beer.)
It\'s a good trick, for sure, but not all amps like it. Old-timey
\'single supply\' amps often have very very poor PSR on V-, because of
course the designer expects you to ground it, duh.
Since CMR is input-referred, you can get _voltage gain_ between V- and
the output, which makes life very exciting. UniversalOpamp2 will _not_
model that correctly.
Very non-green, for sure.
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
R
Ricky
Guest
On Tuesday, March 7, 2023 at 6:05:15â¯PM UTC-5, John S wrote:
I\'m not pressing you for any information. What\'s wrong with your reading comprehension? I\'m simply pointing out, very clearly with a quote, that you stated the UI changed between IV and XVII. If you don\'t know anything about it, how could you know that it changed? If you do know something that changed, you should be able to talk about it, instead of insisting you know nothing.
I don\'t get you. Which of the words I\'m using, do you not understand?
Do you understand now? You said one thing, now you are saying something different. Can you at least acknowledge that?
--
Rick C.
--+ Get 1,000 miles of free Supercharging
--+ Tesla referral code - https://ts.la/richard11209
I\'m not pressing you for any information. What\'s wrong with your reading comprehension? I\'m simply pointing out, very clearly with a quote, that you stated the UI changed between IV and XVII. If you don\'t know anything about it, how could you know that it changed? If you do know something that changed, you should be able to talk about it, instead of insisting you know nothing.
I don\'t get you. Which of the words I\'m using, do you not understand?
Do you understand now? You said one thing, now you are saying something different. Can you at least acknowledge that?
--
Rick C.
--+ Get 1,000 miles of free Supercharging
--+ Tesla referral code - https://ts.la/richard11209
R
Ricky
Guest
On Tuesday, March 7, 2023 at 6:16:20â¯PM UTC-5, John S wrote:
I don\'t expect anything, other than a civil tone in a discussion. You seem to be very frustrated that I\'m not conforming to your ideas of appreciation of a tool. I don\'t believe that we should never speak ill of free tools. If the world were mute about crap software, it would never get any better..
Sorry if I offend your fascist vies of software.
I see you ignored this. But that\'s expected in an ad hominem attack. I\'m sorry you aren\'t mature enough to have a reasonable discussion of a tool. I guess some people get too emotional about inanimate things and software.
--
Rick C.
-+- Get 1,000 miles of free Supercharging
-+- Tesla referral code - https://ts.la/richard11209
I don\'t expect anything, other than a civil tone in a discussion. You seem to be very frustrated that I\'m not conforming to your ideas of appreciation of a tool. I don\'t believe that we should never speak ill of free tools. If the world were mute about crap software, it would never get any better..
Sorry if I offend your fascist vies of software.
I see you ignored this. But that\'s expected in an ad hominem attack. I\'m sorry you aren\'t mature enough to have a reasonable discussion of a tool. I guess some people get too emotional about inanimate things and software.
--
Rick C.
-+- Get 1,000 miles of free Supercharging
-+- Tesla referral code - https://ts.la/richard11209
J
John Larkin
Guest
On Wed, 8 Mar 2023 14:34:33 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
Heresy. Whiteboards run on chocolate.
<pcdhSpamMeSenseless@electrooptical.net> wrote:
On 2023-03-08 12:59, John Larkin wrote:
On Wed, 8 Mar 2023 11:23:50 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:
On 2023-03-08 10:47, John Larkin wrote:
On Tue, 7 Mar 2023 22:15:32 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:
A bunch of my stuff wouldn\'t budge off the peg with those
settings. If you already know what it should look like, why
simulate?
To play with ideas fast day or night, and to get the parts
values right.
I\'ve been known to dork frequency compensation that way too, and to
look at tolerances for filters.
Right. Any interesting control loop is nonlinear.
The last thing I designed by poking at in SPICE was a collapsible
BJT cascode, where the top transistor had to take a bunch of
voltage. When the bottom transistor turned on, the top one
saturated, pulling down its relatively high-Z base bias string, so
the low level was just the sum of the V_CE(sat)s.
I knew that part would work, but needed to figure out what the
turn-off transient would look like. The answer was, \"Nothing too
pretty, but good enough for government work.\" It didn\'t look like
the top transistor would reliably come out of saturation fast
enough to avoid blowing up the bottom one, but a zener on its base
solved that.
It\'s often easier to sim, say, a voltage divider than to do a lot
of math.
Our ideas of \"a lot of math\" are a bit different, but doing that is
no worse than using a calculator.
doing mental arithmetic, because it makes me a much better
troubleshooter.)
A non-trivial voltage divider, with more than two resistors, can be
a pain to work out with a calculator, especially using the parts you
already have in stock.
And Spice sims, with comments, are easy to save in a design notes
folder.
Yup. They go in our git repos too (one repo per project).
I do a lot of mental arithmetic, but it\'s analog computing,
guesswork and not manipulating digits in my head. I usually come in
around 5 or 10% accuracy, which is handy enough in most cases.
I like to make it a game. It\'s memory more than anything--in 1 Hz, 3 uA
of photocurrent has 1 pA shot noise; for Johnson, 60.4 ohms has 1 nV and
16k has 1 pA.
Going up and down decibels is fun too: 1 dB is 12% voltage and 25%
power, pi = 10 dB (voltage), and so 2 pi = 16 dB. A noise contribution
that\'s 6 dB down raises the floor by 1 dB, and it goes down linearly (in
dB) for lower noise.
Doing this at a whiteboard, in a meeting, seems to annoy some people.
This used to be called \"Lightning Empiricism\"; see Williams 1991.
Whiteboards are great fun, when combined with an interesting problem and
one-to-three smart and good-natured colleagues. (And possibly a pitcher
of beer.)
Heresy. Whiteboards run on chocolate.
J
John S
Guest
On 3/8/2023 3:00 PM, Ricky wrote:
What, because I tried it superficially and didn\'t like it so I never
went further? All I knew is that the version and owner changed. You are
one stupid ass.
How can anyone understand you with your flawed ability to communicate? I
acknowledge your lack of logic. Feel better?
Go to hell, asshole.
--
Dogs make me happy. Humans make my head hurt.
What, because I tried it superficially and didn\'t like it so I never
went further? All I knew is that the version and owner changed. You are
one stupid ass.
How can anyone understand you with your flawed ability to communicate? I
acknowledge your lack of logic. Feel better?
Go to hell, asshole.
--
Dogs make me happy. Humans make my head hurt.
J
John S
Guest
On 3/8/2023 3:06 PM, Ricky wrote:
Well, here we agree. You are sorry.
If you are sorry, which was addressed above, then why carry on with the
conversation? I don\'t get emotional about tools. I get emotional about
people who bait others to get their jollies, like yourself. That is all
you\'re doing in this conversation. Trolling. Get lost, D.H.
--
Dogs make me happy. Humans make my head hurt.
Well, here we agree. You are sorry.
If you are sorry, which was addressed above, then why carry on with the
conversation? I don\'t get emotional about tools. I get emotional about
people who bait others to get their jollies, like yourself. That is all
you\'re doing in this conversation. Trolling. Get lost, D.H.
--
Dogs make me happy. Humans make my head hurt.
R
Ricky
Guest
On Wednesday, March 8, 2023 at 6:54:42â¯PM UTC-5, John S wrote:
Ok, so now you are changing your statement again! You have tried it and there was something you didn\'t like. Based on your previous statement that the UI changed, I would have to assume what you didn\'t like was in the UI. But when I ask you what changed in the UI, you get all bent out of shape. Very strange.
https://www.pinterest.com/pin/87890630218951567/
--
Rick C.
-++ Get 1,000 miles of free Supercharging
-++ Tesla referral code - https://ts.la/richard11209
Ok, so now you are changing your statement again! You have tried it and there was something you didn\'t like. Based on your previous statement that the UI changed, I would have to assume what you didn\'t like was in the UI. But when I ask you what changed in the UI, you get all bent out of shape. Very strange.
https://www.pinterest.com/pin/87890630218951567/
--
Rick C.
-++ Get 1,000 miles of free Supercharging
-++ Tesla referral code - https://ts.la/richard11209