Simulating the ideal OP amp

[glorimda]

I'm trying to simulate a ideal op amp as shown in the pic.

Circuit doesn't seem wrong, but it shows the error message.

Is there any problem in my circuit or what is the problem?

And is that the Op amp ideal one?

View attachment 63050

 

[crutschow]

The problem is the opamp symbol needs a model. You need to add the Spice directive ".lib opamp.sub". That includes the ideal op amp model.

 

[audioguru]

The opamp needs a power supply. The simple circuit you show with no capacitors needs a dual-polarity power supply.

 

[ericgibbs]

The opamp needs a power supply. The simple circuit you show with no capacitors needs a dual-polarity power supply.

Its an LTSpice Ideal OPA, [bit like a 741.]

Doesn't require power rails.

The *.lib was missing from his layout

 

[glorimda]

Appreciate for all replies.

ericgibbs// How can I get that op amp? Do I have to add some .lib file? or what do I have to do?

 

[crutschow]

Appreciate for all replies.

ericgibbs// How can I get that op amp? Do I have to add some .lib file? or what do I have to do?

Didn't you read my previous post?

 

[glorimda]

Crutschow// Sorry, but I'm new to LTspice.
.lib opamp.sub => what are they? It seems two files, but first file '.lib' doesn't have a file name.
And where can I get those files?

 

[Jony130]

Download my LTspice file

 

[Roff]

Crutschow// Sorry, but I'm new to LTspice.
.lib opamp.sub => what are they? It seems two files, but first file '.lib' doesn't have a file name.
And where can I get those files?

Open the Help file, click on the Search tab, and type ".lib" (without the quotes) in the search window.
The help file can actually help you.

 

[crutschow]

Crutschow// Sorry, but I'm new to LTspice.
.lib opamp.sub => what are they? It seems two files, but first file '.lib' doesn't have a file name.
And where can I get those files?

You put that in a Spice Directive (look under the "Edit" pull-down menu). The ".lib" is a command to include the file "opamp.sub" which is normally already available in the LTspice library files.

 

[glorimda]

Thanks you so much for your kind explanation. I've finally got the result. !!

 

[unclejed613]

also bear in mind the "ideal" op amp used in spice DOES have a bandwidth limit as well as a gain limit which are parameters you can set. these parameters are set in the right click popup, and are finite (but that doesn't mean you can't set them to ridiculously high values).

 

[Winterstone]

also bear in mind the "ideal" op amp used in spice DOES have a bandwidth limit as well as a gain limit which are parameters you can set. these parameters are set in the right click popup, and are finite (but that doesn't mean you can't set them to ridiculously high values).

I don't know which simulation package you are referring to - however, in PSpice the ideal model OPAMP has no bandwidth limitations. The gain can be set to different values.

 

[Roff]

I don't know which simulation package you are referring to - however, in PSpice the ideal model OPAMP has no bandwidth limitations. The gain can be set to different values.

In LTspice, you can use a voltage-controlled voltage source (e element) if you want an amplifier with no bandwidth limitations and arbitrary gain.