Hello! I encountered a problem when using LTSpice. It is my first time using it and I don't know what I'm doing wrong. I have a circuit and I need Spice to show me the values for node potentials, tensions between every 2 nodes and also intensities between 2 nodes. I made a new schematic, drew the circuit, put the values for resistors, tension source and current source, chose the node to connect to ground and hit run choosing the .op option. All the values I get by doing these are wrong, with really big differences from the true values that I need. A thing that I don't understand is the fact that if I have a wire with, let's say, a resistor, if I click on the wire on the left side of the resistor it displays a voltage and if I click on the right another.And some wires display '???' instead of a value. How can I make it display the proper values? Thank you in advance and I'm sorry if I'm asking something basic.

 

It's pretty hard to diagnose someone's problem with the simulation of a schematic without the schematic being simulated.

At least post a screen shot of the schematic you are trying to use. There might be something obvious, such as no ground reference.

The next step would be to post a screenshot of the results you are seeing with a description of what is wrong about them.

Then you could post the .asc file so that people that are willing to download it and simulate it themselves and give you more detailed feedback.

 

It's pretty hard to diagnose someone's problem with the simulation of a schematic without the schematic being simulated.

At least post a screen shot of the schematic you are trying to use. There might be something obvious, such as no ground reference.

The next step would be to post a screenshot of the results you are seeing with a description of what is wrong about them.

Then you could post the .asc file so that people that are willing to download it and simulate it themselves and give you more detailed feedback.

The problem is that I can't do that due to school regulations...

 

Is there anything preventing you from making a completely unrelated schematic that has the similar problems and showing that?

If this is the most you can give us, then we are very unlikely to be able to help you. This is like calling up an auto mechanic and saying that when you are in your car the radio doesn't work and that you want him to tell you how to listen to a CD. When he requests more information you tell him, "Sorry, that's all I can tell you."

 

The problem is that I can't do that due to school regulations...

Then you need to draw the circuit by hand (gasp) and post it.

 

Then you need to draw the circuit by hand (gasp) and post it.

I imagine that the intent of the prohibition is not against posting LTspice schematics, but of posting schematics for this assignment, whether hand drawn or not.

 

I imagine that the intent of the prohibition is not against posting LTspice schematics, but of posting schematics for this assignment, whether hand drawn or not.

I thought it might be a prohibition on posting from school computers, but you are probably right.

 

I thought it might be a prohibition on posting from school computers, but you are probably right.

Yes, that is the case...I'm really sorry for that.

 

So, again, make up a junk schematic and see if it has the same problems. If not, then that might give you some clues right there. If that doesn't help, then take the original schematic that is causing problems and make changes to it that alter the circuit away from something related to the assignment but that still exhibits the problems you are seeing. Then let's work with that circuit.

 

For example: