Struggling with Latch Circuit Simulation and usage of Switch Model

[SilverSurfer]

I’m pretty new to QSPICE and circuit simulation in general. I’m currently working on a latch circuit and I’m facing some issues with the simulation. I suspect that the problem might be related to the switch model I’m using, but I’m not sure.

This is my model and results

PS. Sry couldn’t upload it as 2 separate files new user restrictions by forum

And I’m using IRF5210 model for MOSFET

The latch circuit is supposed to switch off after the button press as I simulated in the SWMOD but as we can see in the graph V(out) is falling to zero and again its turns ON back, After few days I’m clueless, I thought I’ve made a mistake with the circuit And physically made one on a breadboard to check, And It WORKS, I don’t know why we can’t simulate it then

Kindly help me with this Since I have no background as a circuit person

[ivan1]

Here I think that you’re using too long switching time. Nope, your switch is having weird behaviour, try to add Vt → treshold voltage.

switch.qsch (18.9 KB)

Best regards

[SilverSurfer]

Thank you, @ivan1, I initially thought the solution would take some time, so I was very happy to see your reply and found out what I did wrong.

Using your sketch as the foundation, I altered every parameter and realized that the issue was the lack of a load resistor. Even with the same Vt, I’m now getting the correct latch output.

Thanks again for also showing me the importance of the high-pass filter! Your help was invaluable.

As a reference I’m attaching the output and the circuit and I will mark this as solved