LT spice problems

[rick20]

I would like to fully charge then discharge the capacitor using the two switches . Charge for 50s then discharge for another 50s seconds. Please help me. I am not getting the capacitor to discharge pass half the source voltage.

 

[crutschow]

Here you go.
In your original circuit V2 never turned S2 off so it was on at the same time as S1, drawing kA of current from V1.
I changed the V2 pulse sequence so S2 turns off when S1 turns on, and you get the expected decay of the capacitor to 0V.

Why did use a different switch model for S1 and S2?

 

[ronsimpson]

 

[rick20]

Here you go.
In your original circuit V2 never turned S2 off so it was on at the same time as S1, drawing kA of current from V1.
I changed the V2 pulse sequence so S2 turns off when S1 turns on, and you get the expected decay of the capacitor to 0V.

Why did use a different switch model for S1 and S2?

View attachment 124391

Thank you so much crutschow. Im extremely new to LTspice . I am a first year mechanical engineering student so I' am also very new to electronic circuit building.

 

[rick20]

View attachment 124406

thank you very much for this similar circuit build but I was trying to replicate the result from circuit built on spice that used the open and closed switch feature which LT spice does not have.

 

[crutschow]

circuit built on spice that used the open and closed switch feature which LT spice does not have.

Why do you say that?
LTspice has a switch that you used in your circuit.

 

[rick20]

Pspice has an open switch and a close switch component that allow requires you to input the time when u want it to close for the close switch and when u want it to open for the open switch . LTspice switches are voltage and current controlled.

 

[crutschow]

LTspice switches are voltage and current controlled.

Okay.
But you can generate control signals to make them operate the same as the Pspice switches.

 

[rick20]

Yes but the hard part for me was finding the correct switch model . Will the switch model I used on the circuit I uploaded work in every case for opening and closing switches ?

 

[crutschow]

Will the switch model I used on the circuit I uploaded work in every case for opening and closing switches ?

Yes, you can use the same model for both. Just define the parameters to be appropriate for your application
There's no difference between an opening and a closing switch, they are all the same.
Why did you use two different models in your sim?

 

[rick20]

The circuit was given by the lecturer at my university

 

[crutschow]

The circuit was given by the lecturer at my university

Including the switch models?

 

[rick20]

No I found that on A website . Everyone In using Pspice so they didn’t had any reason to use model for the switches. I got Mac that’s why I’m using LTSpice