It refers to the use of a plumb line. I have one made of bronze.
I have never seen the word used in this context, English is not my native language and here they sometimes use words and abbreviations that confuse me.
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On Wednesday, February 5, 2025 at 01:44:54 PM GMT-5, Richard Andrews via groups.io <richardandrews.ma@...> wrote:
My Grandfather used to say "make sure it's plumb" meaning make sure it's perfectly vertical. He used to be a handyman and mason.
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Re: Over-voltage protection circuit does not work as expected
Jerzy, the problem is not the speed at which the overvoltage is detected, but whether it is a transient or not. You have to wait and see if the voltage returns to low values (a ringing) or if it remains high. Only in the second case do you have to trigger the triac and open the circuit. Otherwise, you will open the circuit incorrectly ??
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Re: Any Good Reason to Create a Hierarchical Connector and Conductors to Route (Plumb) Ground Out of a Hierarchical Schematic
Hello All:
?
On Wed, Feb 5, 2025 at 02:06 AM, eewiz wrote:
On Wed, Feb 05, 2025 at 9:25 AM, Andy I wrote:
?
I am pretty sure this has nothing to do with version 24.1.1.? I think LTspice has always behaved this way - going back at least as far as LTspice IV and probably earlier.
?
I did not wish to imply that 24.1.1 had any special status related to the findings I wrote about.
I simply meant to inform others that the work was conducted on 24.1.1.
?
On Wed, Feb 5, 2025 at 02:06 AM, eewiz wrote:
After running the sim, nothing changes outside the block, still ground on one side of the resistor and V(n030) on the other side connected to the RTN hierarchical connector.
Inside the block, the RTN hierarchical connector still says "Click to plot V(n030)" but, the net connected to that RTN hierarchical connector now says "This is ground."
On Wed, Feb 05, 2025 at 9:25 AM, Andy I wrote:
That observation is incorrect.? The net that LTspice labels "ground" in the lower-level schematic, is not actually ground when it becomes connected to the higher-level schematic.? Therefore the resistor outside the block is NOT connected to ground on both ends.? It must not disappear from the netlist, because it really is there!
?
Now I understand what is happening.
On the top level, if that hierarchical net is disconnected from node 0 and then connected to a net with 1 volt, it will effect operation of the sub-circuit as expected even though that net remains connected to node 0 inside the sub-circuit.
LTspice does ignore those connections to node 0 made within a sub-circuit except:
?
Inside the sub-circuit, probing that net says "This is ground."
Imagine that net is connected to the anode of a TL431 2.5V reference.
If you plot V(cathode)-V(anode) across the TL431 you get 2.5V.
If you plot V(cathode) you get 3.5V.
You see a quite confusing output, 3.5V above ground, from a 2.5V reference, because LTspice does not show the true 1 volt on that net.
It always says "This is ground." when probing that net, that in this example, actually has 1 volt on it.
?
So, to avoid future probing confusion, I will remove (label 0) ground symbols from sub-circuit schematics and physically re-connect isolated net segments.
?
Tony Casey suggested using the COM net (with its own triangular symbol) but, that has the same issue.
The COM symbols make the connected net say "This is node X1:COM." which is no better than node 0's "This is ground." message.
In either case, you can't see if there is any voltage on the net and you can't plot the net voltage because LTspice thinks it's a ground net.
?
On Wed, Feb 05, 2025 at 9:25 AM, Andy I wrote:
It is actually reasonable to draw a lower-level schematic, where a net is called "ground" locally (using the triangle symbol), but also goes to an I/O pin (with a box around it).? That ENABLES you to selectively "override that ground".? If the higher-level schematic doesn't connect to the pin, it remains ground.? If the higher-level schematic connects it to +150 V, that net becomes not-grounded and has +150 V on it.? Think of it as a feature you didn't realize was there.
?
Yes, I understand but, the issue is that the probe won't show the +150 V on that net and can't plot the +150 V on that net and can't .meas the +150 V on that net, unless all ground symbols are removed from that net.
?
All for now.
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Re: Any Good Reason to Create a Hierarchical Connector and Conductors to Route (Plumb) Ground Out of a Hierarchical Schematic
It is all about context.? Context changes everything.
?
I uploaded "Hierarchy_netnames.zip" which illustrates how the netnames change due to context.? It has five instances of lower-level schematics, each consisting of one resistor.? The pins connect to its symbol, and from there to nets on the top-level schematic.? LTspice "connects" them by making their netnames the same, so they are truly ideal connections with zero added resistance.
?
(1)? Open MyRes1.asc, one of the lower-level schematics.? Hover over the top net and see that its netname in this view is "Top".? The context here is in isolation, not part of the main simulation.
?
(2)? Then open Top_Level.asc which is the top-level schematic.? Now right-click on the X1 symbol and click "Open Schematic".? This opens that particular instance (X1) of MyRes1.asc.? Hover over the top net.? Notice its netname has changed from "Top" to "AAA".? It inherited the netname from the top-level schematic.? That is what happens whenever a subcircuit or a lower-level schematic is connected to nets in the next higher schematic.? The netnames in the lower-level schematic effectively change to match those of the higher schematic.
?
This is where context matters.? By opening MyRes1.asc in isolation (by double-clicking on it in Windows Explorer), it has no context, and it must use the netnames printed on that schematic even though they will not be used.? By opening MyRes1.asc from the top-level schematic, you have given it context.? You have chosen that one instance (X1) of that lower-level schematic, and LTspice rewards you by showing the adjusted netnames as they exist in the main circuit.
?
(3)? Open MyRes3.asc from Windows.? Hover over the top and bottom nets and note their netnames.? The upper netname is "Top" and the lower netname is 0 or ground.? That is correct in this context because connections have not been made to any other schematic's nets.? Those are temporary netnames.
?
(4)? Now open Top_Level.asc again.? Do these steps in this order:
- Right-click on the X3 symbol and click "Open Schematic".
- Go back to the top-level schematic and click Run.
- Go back to the schematic representing?X3, which is already open in LTspice.
- Hover over the nets and note their new netnames.
(LTspice has a wee synchronization issue, making it necessary to do these steps in this order.)? The former "Top" net has inherited the netname "DDD" from the Top_Level schematic.? The bottom netname is no longer ground!? It has inherited the netname "EEE" from the Top_Level schematic, replacing node 0.
?
Like I say, context changes everything.? By viewing the schematic of that one instance (X3) of the lower-level schematic, you see what the netnames change to.? What you thought was ground, is now a different net, named "EEE".? That is true only in this context.? Without context, the lower net looked like ground, which was a temporary netname.? Context is everything.
?
What's going on is basically this:? On lower-level schematics or in subcircuits, expanding the SPICE netlist causes every net that goes to a pin to have its netname changed.? All of them inherit the netnames of the nets they connect to in the next higher hierarchy level.? LTspice does that uniformly, making no exception for node 0 - even node 0 changes to another name.? You see that only in the context where it is part of the top-level schematic.? Without that context, it appears to be ground, but that was just a place-holder.
?
I was wrong about something.? I thought that if you left the net not connected to anything in the top-level schematic, it would revert to ground.? But alas, it does not.? Even floating pins without wires have netnames, and it picks up that netname instead of defaulting to ground.? Therefore, the usefulness of grounding a net on a lower-level schematic, and simultaneously bringing it out on a pin that can go somewhere else, seems awfully limited -- to the point that I don't see very much reason for doing that.? I can envision a few reasons to do it anyway, to modify one schematic to use as a lower-level block without making extensive manual edits.? But?it seems not useful to draw a new schematic that way.
?
I hope some of this makes sense.
?
Andy
?
?
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Re: Over-voltage protection circuit does not work as expected
I get an aborting notice. Sim quits before it starts with "unknown schematic syntax: V".
?
I am running version 4.23.
?
I can't run it on my 64-bit system because it is bricked. I have a new system coming later today.
?
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Re: Trying to use .MOD file in schematic
Model files (.MOD, .LIB, .SUB, .TXT, .whatever) can be added either to a schematic (.ASC file), or to a symbol (.ASY file) that then is placed on the schematic.? Exactly how and where you add the path to the model file, depends on which one it is.? We need more details to answer your concerns.
?
Andy
?
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Re: Trying to use .MOD file in schematic
On Wed, Feb 5, 2025 at 10:36 PM, <william.finley@...> wrote:
I did .include "the file path to the mod file" but it says I need to right click a general part and include the subcircuit name for the value and erase spice model.
What said all that?? Did you watch a YouTube video?
Every time I put a generic part on the schematic and left click, it does not give me that table with all the categories I am suppose to fil in. It give me things like inductance, parallel capacitance, parallel resistance and DC resistance. How do I enact this .MOD file into a component so I can use it? Thanks.?
What kind of component are you doing this with?
?
If it is an inductor, and if you need to make special edits to the component, do not either left-click or right-click on the inductor symbol.? Instead, use Ctrl-Right-click on the symbol.? That brings up the General Attribute Editor, where you can add to or edit each attribute.? If you just Right-clicked, then you get the special inductor editor that has special fields for things like Series and Parallel Resistance, and I'm guessing those were not the fields you wanted to edit.
?
What is this .MOD file for?? Is it for an inductor?? For a transistor?? For a diode?? For an IC?
?
It is rather unusual to use a model or .MOD file for an inductor, but I can't tell what you are trying to do with it.? Can you tell us more?
?
Andy
?
?
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Trying to use .MOD file in schematic
I did .include "the file path to the mod file" but it says I need to right click a general part and include the subcircuit name for the value and erase spice model. Every time I put a generic part on the schematic and left click, it does not give me that table with all the categories I am suppose to fil in. It give me things like inductance, parallel capacitance, parallel resistance and DC resistance. How do I enact this .MOD file into a component so I can use it? Thanks.?
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Re: Over-voltage protection circuit does not work as expected
Dave, thanks for the advice. The ramp down is not needed indeed. Anyway, the original model of TLV1805 is a nice find. ? Jurek ? From: <[email protected]> on behalf of "Bell, Dave via groups.io" <Dave.Bell@...>
Reply to: <[email protected]>
Date: Wednesday, 5 February 2025 at 22:09
To: "[email protected]" <[email protected]>
Subject: Re: [LTspice] Over-voltage protection circuit does not work as expected
Resent from: <Dave.Bell@...>
Resent date: Wed, 05 Feb 2025 13:09:29 -0800 You¡¯re right - it does work! I found the output voltage curve a little confusing by itself, with the ramp Up and ramp Down. But reducing the output cap to 10u or increasing the load to 100 ohms, it became clear; it was just the slooow decay that looked weird. ? Dave ?
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From: [email protected] <[email protected]> On Behalf Of jerzy przezdziecki via groups.io
Sent: Wednesday, February 05, 2025 12:51 PM
To: [email protected]
Subject: EXTERNAL: Re: [LTspice] Over-voltage protection circuit does not work as expected? Yes, it¡¯s uploaded in TEMP as ¡°TLV1805_overvoltage_protection_circuit_works¡± ? Jurek ? Is there a circuit for this thread? Ild like to look at it myself when i get home. ? On Wed, Feb 5, 2025 at 3:41 PM, jerzy przezdziecki via groups.io I can imagine that crowbar is much better, but I would not be afraid about transients. This chip is extremally fast, a few ns. So ¨C as you said ¨C the TLV1805 is made for this purpose. Jurek ? I understand that overvoltage protection (OVP) must be a very simple and reliable circuit.
I've had a lot of problems with this circuit because sudden load variations can cause transients in the output voltage and reach high values triggering the triac! That's terrible.
Extreme situations can generate noise and lead to malfunctioning protection circuits.
My overvoltage detection, for this reason, is done by simple zener diodes and only components like the TLV1805 are suitable, as they have been designed for this purpose.
Because of these problems, in one specific case I used a microcontroller to trigger the crowbar. The microcontroller was able to distinguish between an overvoltage and a transient.
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Re: Over-voltage protection circuit does not work as expected
You¡¯re right - it does work!
I found the output voltage curve a little confusing by itself, with the ramp Up and ramp Down.
But reducing the output cap to 10u or increasing the load to 100 ohms, it became clear; it was just the slooow decay that looked weird.
?
Dave
?
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From: [email protected] <[email protected]>
On Behalf Of jerzy przezdziecki via groups.io
Sent: Wednesday, February 05, 2025 12:51 PM
To: [email protected]
Subject: EXTERNAL: Re: [LTspice] Over-voltage protection circuit does not work as expected
?
Yes, it¡¯s uploaded in TEMP as ¡°TLV1805_overvoltage_protection_circuit_works¡±
?
Jurek
?
Is there a circuit for this thread? Ild like to look at it myself when i get home.
?
On Wed, Feb 5, 2025 at 3:41 PM, jerzy przezdziecki via groups.io
I can imagine that crowbar is much better, but I would not be afraid about transients. This chip is extremally fast, a few ns. So ¨C as you said ¨C the TLV1805 is made for this purpose.
Jurek
?
I understand that overvoltage protection (OVP) must be a very simple and reliable circuit.
I've had a lot of problems with this circuit because sudden load variations can cause transients in the output voltage and reach high values triggering the triac! That's terrible.
Extreme situations can generate noise and lead to malfunctioning protection circuits.
My overvoltage detection, for this reason, is done by simple zener diodes and only components like the TLV1805 are suitable, as they have been designed for this purpose.
Because of these problems, in one specific case I used a microcontroller to trigger the crowbar. The microcontroller was able to distinguish between an overvoltage and a transient.
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Re: Over-voltage protection circuit does not work as expected
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On Wed, Feb 5, 2025 at 3:51 PM, jerzy przezdziecki via groups.io <jprzezdziecki@...> wrote: Yes, it¡¯s uploaded in TEMP as ¡°TLV1805_overvoltage_protection_circuit_works¡± ? Jurek ? From: <[email protected]> on behalf of "Richard Andrews via groups.io" <richardandrews.ma@...>
Reply to: <[email protected]>
Date: Wednesday, 5 February 2025 at 21:49
To: <[email protected]>
Subject: Re: [LTspice] Over-voltage protection circuit does not work as expected
Resent from: <richardandrews.ma@...>
Resent date: Wed, 05 Feb 2025 12:49:16 -0800 Is there a circuit for this thread? Ild like to look at it myself when i get home. ? On Wed, Feb 5, 2025 at 3:41 PM, jerzy przezdziecki via groups.io <jprzezdziecki@...> wrote: I can imagine that crowbar is much better, but I would not be afraid about transients. This chip is extremally fast, a few ns. So ¨C as you said ¨C the TLV1805 is made for this purpose. Jurek ? I understand that overvoltage protection (OVP) must be a very simple and reliable circuit.
I've had a lot of problems with this circuit because sudden load variations can cause transients in the output voltage and reach high values triggering the triac! That's terrible.
Extreme situations can generate noise and lead to malfunctioning protection circuits.
My overvoltage detection, for this reason, is done by simple zener diodes and only components like the TLV1805 are suitable, as they have been designed for this purpose.
Because of these problems, in one specific case I used a microcontroller to trigger the crowbar. The microcontroller was able to distinguish between an overvoltage and a transient.
|
Re: Over-voltage protection circuit does not work as expected
Yes, it¡¯s uploaded in TEMP as ¡°TLV1805_overvoltage_protection_circuit_works¡± ? Jurek ? From: <[email protected]> on behalf of "Richard Andrews via groups.io" <richardandrews.ma@...>
Reply to: <[email protected]>
Date: Wednesday, 5 February 2025 at 21:49
To: <[email protected]>
Subject: Re: [LTspice] Over-voltage protection circuit does not work as expected
Resent from: <richardandrews.ma@...>
Resent date: Wed, 05 Feb 2025 12:49:16 -0800 Is there a circuit for this thread? Ild like to look at it myself when i get home. ?
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On Wed, Feb 5, 2025 at 3:41 PM, jerzy przezdziecki via groups.io <jprzezdziecki@...> wrote: I can imagine that crowbar is much better, but I would not be afraid about transients. This chip is extremally fast, a few ns. So ¨C as you said ¨C the TLV1805 is made for this purpose. Jurek ? I understand that overvoltage protection (OVP) must be a very simple and reliable circuit.
I've had a lot of problems with this circuit because sudden load variations can cause transients in the output voltage and reach high values triggering the triac! That's terrible.
Extreme situations can generate noise and lead to malfunctioning protection circuits.
My overvoltage detection, for this reason, is done by simple zener diodes and only components like the TLV1805 are suitable, as they have been designed for this purpose.
Because of these problems, in one specific case I used a microcontroller to trigger the crowbar. The microcontroller was able to distinguish between an overvoltage and a transient.
|
Re: Over-voltage protection circuit does not work as expected
Is there a circuit for this thread? Ild like to look at it myself when i get home.
On Wed, Feb 5, 2025 at 3:41 PM, jerzy przezdziecki via groups.io <jprzezdziecki@...> wrote: I can imagine that crowbar is much better, but I would not be afraid about transients. This chip is extremally fast, a few ns. So ¨C as you said ¨C the TLV1805 is made for this purpose. Jurek ? I understand that overvoltage protection (OVP) must be a very simple and reliable circuit.
I've had a lot of problems with this circuit because sudden load variations can cause transients in the output voltage and reach high values triggering the triac! That's terrible.
Extreme situations can generate noise and lead to malfunctioning protection circuits.
My overvoltage detection, for this reason, is done by simple zener diodes and only components like the TLV1805 are suitable, as they have been designed for this purpose.
Because of these problems, in one specific case I used a microcontroller to trigger the crowbar. The microcontroller was able to distinguish between an overvoltage and a transient.
|
Re: Over-voltage protection circuit does not work as expected
I can imagine that crowbar is much better, but I would not be afraid about transients. This chip is extremally fast, a few ns. So ¨C as you said ¨C the TLV1805 is made for this purpose. Jurek ? I understand that overvoltage protection (OVP) must be a very simple and reliable circuit.
I've had a lot of problems with this circuit because sudden load variations can cause transients in the output voltage and reach high values triggering the triac! That's terrible.
Extreme situations can generate noise and lead to malfunctioning protection circuits.
My overvoltage detection, for this reason, is done by simple zener diodes and only components like the TLV1805 are suitable, as they have been designed for this purpose.
Because of these problems, in one specific case I used a microcontroller to trigger the crowbar. The microcontroller was able to distinguish between an overvoltage and a transient.
|
Re: Over-voltage protection circuit does not work as expected
I understand that overvoltage protection (OVP) must be a very simple and reliable circuit.
I've had a lot of problems with this circuit because sudden load variations can cause transients in the output voltage and reach high values triggering the triac! That's terrible.
Extreme situations can generate noise and lead to malfunctioning protection circuits.
My overvoltage detection, for this reason, is done by simple zener diodes and only components like the TLV1805 are suitable, as they have been designed for this purpose.
Because of these problems, in one specific case I used a microcontroller to trigger the crowbar. The microcontroller was able to distinguish between an overvoltage and a transient.
?
?
?
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My Grandfather used to say "make sure it's plumb" meaning make sure it's perfectly vertical. He used to be a handyman and mason.
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Re: Over-voltage protection circuit does not work as expected
As much as a defective Power MOSFET can prevent a
series-protected voltage limiter, a problem with the crowbar
thyristor or its control circuit can defeat its purpose.
Nothing is ever perfect.
Le 05/02/2025 ¨¤ 16:41, Udo
Huhn-Rohrbacher via groups.io a ¨¦crit?:
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I would not designate the proposed circuit as an
overvoltage protection circuit. At most it's something like a
"voltage clipper" or "voltage limiter" for excessive input
voltage excursions.
Let's assume there are any failures within the control
circuit, or a defective Power-MOSFet, or even overvoltages,
coming from external sources directly to the Load, then you
will get in trouble with that circuit.
A true overvoltage protection circuit requires a crowbar
arrangement, as well known in the power electronics industry.
Best regards
Udo??
Am Mi., 5. Feb. 2025 um
15:40?Uhr schrieb jerzy przezdziecki via
<jprzezdziecki= [email protected]>:
Hello,
?
I have uploaded circuit that
finally works as executed with a good TLV1805 model
found online.
The problem was the ic. I
have used a voltage comparator from the LTSpice
library list with an open collector ¨C instead of an
original TLV1805 push-pull one.
This made a simulation not
working properly. So everything was fine with the
PMOS.
?
Anyway thanks to all for
advices.
?
Jurek
?
Two other suggestions:
Keep Vcc at 36V, but add a
separate PWL(0 0 1 36) source to the comparator
signal input, rather than the R2/R3 divider.
THEN(!) swap the + & -
inputs. As is, it turns the output FET ON when the
test voltage exceeds the Zener.
?
Dave
?
?
Works a heck of a lot better,
with the S pin NOT grpinded¡
As David Schultz suggested,
maybe add the bypass cap between B and S,. but don¡¯t
ground it ¨C that forces the out out to an
open/pulled-up state.
?
Dave
?
?
Isn't that
what it is supposed to do?? 19V is not overvoltage
so you would expect the mosfet to conduct.
--
Dipl.Ing.Udo
Huhn-Rohrbacher
Albert-Kratz-Str.1
D-75180 Pforzheim
phone: +497231-352339
fax: +497231-140338
mobile: +491523-3612096
E-mail: u.huhn.rohrbacher@...
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Re: Over-voltage protection circuit does not work as expected
I would not designate the proposed circuit as an overvoltage protection circuit. At most it's something like a "voltage clipper" or "voltage limiter" for excessive input voltage excursions. Let's assume there are any failures within the control circuit, or a defective Power-MOSFet, or even overvoltages, coming from external sources directly to the Load, then you will get in trouble with that circuit.
A true overvoltage protection circuit requires a crowbar arrangement, as well known in the power electronics industry.
Best regards Udo?? Am Mi., 5. Feb. 2025 um 15:40?Uhr schrieb jerzy przezdziecki via <jprzezdziecki= [email protected]>:
Hello, ? I have uploaded circuit that finally works as executed with a good TLV1805 model found online. The problem was the ic. I have used a voltage comparator from the LTSpice library list with an open collector ¨C instead of an original TLV1805 push-pull one. This made a simulation not working properly. So everything was fine with the PMOS. ? Anyway thanks to all for advices. ? Jurek ? Two other suggestions: Keep Vcc at 36V, but add a separate PWL(0 0 1 36) source to the comparator signal input, rather than the R2/R3 divider. THEN(!) swap the + & - inputs. As is, it turns the output FET ON when the test voltage exceeds the Zener. ? Dave ? ? Works a heck of a lot better, with the S pin NOT grpinded¡ As David Schultz suggested, maybe add the bypass cap between B and S,. but don¡¯t ground it ¨C that forces the out out to an open/pulled-up state. ? Dave ? ? Isn't that what it is supposed to do?? 19V is not overvoltage so you would expect the mosfet to conduct.
-- Dipl.Ing.Udo Huhn-Rohrbacher Albert-Kratz-Str.1 D-75180 Pforzheim phone: +497231-352339 fax: +497231-140338 mobile: +491523-3612096 E-mail: u.huhn.rohrbacher@...
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Re: In need of some zeners or maybe model them myself
On Tue, Feb 4, 2025 at 10:45 PM, Andy I wrote:
I am right in assuming therefore that, as long as the model parameters match the datasheet, and therefore the device I'm trying to model, I'll be golden, yes?
Tough question.? Simulations are never quite correct, but good models should yield good results in most cases.? There can be exceptions, though, so being 'golden' is never guaranteed.
?
Makes sense.
If you can verify the models, by comparing them not just with the datasheets but with other measurements of real parts, you are usually in good shape.? Comparisons with datasheets are pretty good; going further (if you can) gives you better confidence.? Many SPICE users don't do either.? Sometimes they are lucky, sometimes not.
?
Andy
?
?
I have everything I need here at work and, at home. I've also done plenty of voltage readings of this device in the past but, like I said, being no one here actually understands how the circuit was designed exactly, I've only been able to get so far in trying to understand what the originators of the circuit were thinking when they designed this circuit 40 years ago. Lol! I ain't giving up any time soon. Just the opposite, I plan on figuring this f***er out! Lol!
?
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Re: Any Good Reason to Create a Hierarchical Connector and Conductors to Route (Plumb) Ground Out of a Hierarchical Schematic
Ah, yes. I had forgotten that. Thanks.
--
Regards,
Tony
On 05/02/2025 14:21, Andy I via
groups.io wrote:
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Show quoted text
Technically, the
"hidden" connection is to a not-hidden pin on the A-device
symbol's lower left corner.? If the pin is left floating, which is
the normal way to use them, LTspice makes a hidden to node 0.? If
the pin goes anywhere on your schematic, the connection to node 0
is broken, causing the output currents to be sourced from
something other than node 0.
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Marcelo_Pessoa
eewiz
Bell, Dave
Tony Casey