I have learned more about this in less time from you than I have in several hours of other people's videos. They all assume I know what to click on, or what the other ways of doing the same thing is. Your skill at teaching is sorely needed for those not familiar with using this software on a daily basis. Thank you.
Excellent video. You have a gifted way of explaining LTspice, thank you. By the way, a comment for the slide at 1:54. When reviewing the LTspice help for the .include command, I see that LTspice now puts "user stuff" into %LOCALAPPDATA%\LTspice (which, for me, works out to C:\Users\Claude\AppData\Local\LTspice). The LTspice menu Tools>Control Panel tab called "Sym. and Lib. Search Paths" lets me create directories that don't junk up the default install files, and the Waveforms tab lets me specify a directory to put all the work files (the .raw, .plt, and .log files) so these don't clutter up the symbol and library directories.
Very good video. I've been looking for a decent explanation of subcircuits and models, this is the first one that was able to answer some questions I had about them.
Sir, good video on LTspice. I would recommend you introduce net lists. Net lists are fundamental to understanding sub circuit modeling. Also allows individuals to review how they model is wired up in their circuit model. Thank you.
Yes, I agree. Using the term "Node" implies a Nodal analysis. This is not a nodal analysis, per se. It's defining connection points between the subcircuit and the schematic in which that subcuit is used. So it appears we have two sets of connections: Wires between the components in the subcircuit, and then connection points from the subcuit to the schematic. Looking at the subcircuit definitions for things like op amps, I'm sure there's a lot more to it than this, but this help my dim mind understand what's going on. For what it's worth, the menu command View > Spice Netlist, you can see how LTspice defines the automatically generated netnames when a simulation is run. Also, when I'm looking at a measurement (like Vn002, for example), I'm always asking myself where, exactly, is the net in the schematic. If you click Ctrl+F, and enter the netname (like n002 for V(n002)) in the search box in the upper righthand corner, the network will be highlighted in the schematic.
As a complete newbie to LTspice, this is the best video I have seen so far. One quick question, I don't see anywhere where you define number one as being in, number two as being out, and number three is being ground when putting the sub circuit into the symbol. Does it know based on what's on the left, the right, and on the bottom? Many thanks for your time.
wow.. this should be one of the 1st videos to watch. Analog Devices AD202KN iso-amp has cad info but how to get it in the LTspice simulation for their own product? 🐬 looks like draw the sub-circuit and make one? there is one somewhere for the design people?? so here goes the re-engineer mode in to get a LTspice simulation model 🧐 🤣
Great explanation! Thanks for the video. Had a doubt: When we create the symbol, how does LTSpice automatically identify that 'IN' is to be associated to node 1, 'OUT' to node 2 and 'GND' to node 3? What if I wanted node 2 to be grounded and node 3 to be output, is there any particular method to specify this? Also, what happens when there are more than 3 nodes, but I only assign IN, OUT and GND at the symbol?
I guess the best way is to assign the same name in the symbol and SPICE sub-circuit. Here is the answer from ChatGPT In LTspice, linking the symbol ports of a custom symbol to a SPICE subcircuit model involves several steps to ensure that the symbol correctly interfaces with the underlying netlist of the subcircuit. Here’s how you can do it: 1. **Create the Subcircuit (`.subckt`) Definition:** - Begin by defining your subcircuit in a SPICE model file. This involves using the `.subckt` command followed by the name of the subcircuit and a list of nodes. For example: ``` .subckt MySubcircuit in+ in- out * Your subcircuit components go here .ends MySubcircuit ``` 2. **Create a Symbol for the Subcircuit:** - You need a graphical symbol to represent your subcircuit in the schematic editor. LTspice allows you to create a new symbol using its Symbol Editor. - Go to `File` > `New Symbol` and design your symbol. Place pins where you need them to match the nodes in your subcircuit definition. Each pin will correspond to a node (port) in your subcircuit. 3. **Assign Names to Symbol Pins:** - Select each pin and assign it a name that matches the node names in your `.subckt` definition. This is crucial because LTspice uses these names to link the symbol to the subcircuit nodes. - To name a pin, right-click on it, select `Attributes`, and then enter the name in the `Label` field. 4. **Save the Symbol:** - Save your symbol with a suitable name, preferably the same as your subcircuit for ease of recognition. 5. **Link the Symbol to the Subcircuit:** - Place the symbol in a schematic. Right-click on it and select `Pick New Subcircuit`. - Navigate to the SPICE model file where your subcircuit is defined and select it. This step links your graphical symbol to the SPICE subcircuit definition. 6. **Testing the Subcircuit:** - Once everything is set up, place the symbol in your schematic, connect it as needed, and run simulations to test its functionality. By following these steps, you ensure that each port on your symbol correctly corresponds to a node in your SPICE subcircuit definition, allowing for accurate simulations in LTspice.
Thank you so much, sir! Very informative video! I have a question: how the subcircuit and symbols are connected? What will happen if we have 2 subcircuit with the same connection, eg. only the resistor value is different. And we include both in the schematic. How can the symbol tell which subcircuit to use?
My installation is a bit weird. Everything was put under User > AppData > and the lib is a subdirectory that is saved as a zip, and I can't save anything in it. Anyone else having this issue?
If LTSpice is open source, I should be able to download the source code somewhere. Can you provide a link to the source download? Thanks for the video!
I have learned more about this in less time from you than I have in several hours of other people's videos. They all assume I know what to click on, or what the other ways of doing the same thing is. Your skill at teaching is sorely needed for those not familiar with using this software on a daily basis. Thank you.
Finally well explained, most assume that people know all the stuff. Awesome series!!
Thanks. Very useful. A part of LTSpice i didn't even know existed. I'm still really new to all this.
Excellent video. You have a gifted way of explaining LTspice, thank you. By the way, a comment for the slide at 1:54. When reviewing the LTspice help for the .include command, I see that LTspice now puts "user stuff" into %LOCALAPPDATA%\LTspice (which, for me, works out to C:\Users\Claude\AppData\Local\LTspice). The LTspice menu Tools>Control Panel tab called "Sym. and Lib. Search Paths" lets me create directories that don't junk up the default install files, and the Waveforms tab lets me specify a directory to put all the work files (the .raw, .plt, and .log files) so these don't clutter up the symbol and library directories.
TNX FOR THE INFO ON FILE LOCATION
😁
Best tutorial for LTspice
Very good video. I've been looking for a decent explanation of subcircuits and models, this is the first one that was able to answer some questions I had about them.
Finaly, a well explained tutorial for newbies
Sir, good video on LTspice. I would recommend you introduce net lists. Net lists are fundamental to understanding sub circuit modeling. Also allows individuals to review how they model is wired up in their circuit model. Thank you.
Yes, I agree. Using the term "Node" implies a Nodal analysis. This is not a nodal analysis, per se. It's defining connection points between the subcircuit and the schematic in which that subcuit is used. So it appears we have two sets of connections: Wires between the components in the subcircuit, and then connection points from the subcuit to the schematic. Looking at the subcircuit definitions for things like op amps, I'm sure there's a lot more to it than this, but this help my dim mind understand what's going on. For what it's worth, the menu command View > Spice Netlist, you can see how LTspice defines the automatically generated netnames when a simulation is run. Also, when I'm looking at a measurement (like Vn002, for example), I'm always asking myself where, exactly, is the net in the schematic. If you click Ctrl+F, and enter the netname (like n002 for V(n002)) in the search box in the upper righthand corner, the network will be highlighted in the schematic.
Thanks for your tutorials on LTSpice!
Thanks for your effort. It's very useful video that helps to beginners of LTspice program.
Great tutorial, learned some new things in LTSpice, thanks!
Thanks very much. Great help for me to start with subcircuits.
Thank you very much. Now I can easyly organize my models.
Appreciated - I also like your method of explaining.
Great， like it.
Thank you. This was very helpful.
Learning a lot!
Awesome!
As a complete newbie to LTspice, this is the best video I have seen so far. One quick question, I don't see anywhere where you define number one as being in, number two as being out, and number three is being ground when putting the sub circuit into the symbol. Does it know based on what's on the left, the right, and on the bottom? Many thanks for your time.
@ 18:12 netlist order for pin in is 1.that means the node 1 in subcircuit is equal to in.
Thank you teacher.
wow.. this should be one of the 1st videos to watch. Analog Devices AD202KN iso-amp has cad info but how to get it in the LTspice simulation for their own product? 🐬
looks like draw the sub-circuit and make one? there is one somewhere for the design people?? so here goes the re-engineer mode in to get a LTspice simulation model 🧐 🤣
Great explanation! Thanks for the video. Had a doubt:
When we create the symbol, how does LTSpice automatically identify that 'IN' is to be associated to node 1, 'OUT' to node 2 and 'GND' to node 3?
What if I wanted node 2 to be grounded and node 3 to be output, is there any particular method to specify this? Also, what happens when there are more than 3 nodes, but I only assign IN, OUT and GND at the symbol?
That's my question, too.
I guess the best way is to assign the same name in the symbol and SPICE sub-circuit. Here is the answer from ChatGPT
In LTspice, linking the symbol ports of a custom symbol to a SPICE subcircuit model involves several steps to ensure that the symbol correctly interfaces with the underlying netlist of the subcircuit. Here’s how you can do it:
1. **Create the Subcircuit (`.subckt`) Definition:**
- Begin by defining your subcircuit in a SPICE model file. This involves using the `.subckt` command followed by the name of the subcircuit and a list of nodes. For example:
```
.subckt MySubcircuit in+ in- out
* Your subcircuit components go here
.ends MySubcircuit
```
2. **Create a Symbol for the Subcircuit:**
- You need a graphical symbol to represent your subcircuit in the schematic editor. LTspice allows you to create a new symbol using its Symbol Editor.
- Go to `File` > `New Symbol` and design your symbol. Place pins where you need them to match the nodes in your subcircuit definition. Each pin will correspond to a node (port) in your subcircuit.
3. **Assign Names to Symbol Pins:**
- Select each pin and assign it a name that matches the node names in your `.subckt` definition. This is crucial because LTspice uses these names to link the symbol to the subcircuit nodes.
- To name a pin, right-click on it, select `Attributes`, and then enter the name in the `Label` field.
4. **Save the Symbol:**
- Save your symbol with a suitable name, preferably the same as your subcircuit for ease of recognition.
5. **Link the Symbol to the Subcircuit:**
- Place the symbol in a schematic. Right-click on it and select `Pick New Subcircuit`.
- Navigate to the SPICE model file where your subcircuit is defined and select it. This step links your graphical symbol to the SPICE subcircuit definition.
6. **Testing the Subcircuit:**
- Once everything is set up, place the symbol in your schematic, connect it as needed, and run simulations to test its functionality.
By following these steps, you ensure that each port on your symbol correctly corresponds to a node in your SPICE subcircuit definition, allowing for accurate simulations in LTspice.
Thank you so much, sir! Very informative video! I have a question: how the subcircuit and symbols are connected? What will happen if we have 2 subcircuit with the same connection, eg. only the resistor value is different. And we include both in the schematic. How can the symbol tell which subcircuit to use?
ERROR: can not include myfilter.sub file, when running the simulation. Where can i be wrong ?
Superb....
My installation is a bit weird. Everything was put under User > AppData > and the lib is a subdirectory that is saved as a zip, and I can't save anything in it. Anyone else having this issue?
I have followed whole procedure. But I still get error Box. Any solution ?
Brilliant! I just don't understand all these tech term obfuscations.
excellent.
If LTSpice is open source, I should be able to download the source code somewhere. Can you provide a link to the source download? Thanks for the video!
LTSpice is not open source, it's just free. He misspoke or misunderstood when he said that