Well when you start out without describing things better, it sounds a lot like spam bot posts which are getting more prevalent here lately. It’s not that we want to roast you.
As Hermit pointed out, ac mains are not to be toyed with, and we discourage putting mains on a pcb (unless that is your job and you know what you are doing and following regulations for creepage/clearance and all that). I have been an EE for four decades and mains voltage is something I avoid unless I am wiring a circuit breaker panel.
However, if you want to simulate it that is pretty safe You didn’t mention that up front. So the transformer in spice just needs the proper turns ratio. If you want 120VACrms in, and 12VACrms out, it is a 10:1 ratio, or for 9VACrms out a 13:1 ratio. Spice models for diodes and caps are standard. There are likely regulator models, I don’t know the details. Simulate varying load current and bulk cap affects the peaks and valleys of the Vunreg. You need a 60Hz 120VACrms (not peak or pp) sinusoidal source, transient simulation for a few hundred milliseconds (at 60 Hz each half cycle of the full-wave-rectified signal is 8.3ms). Then add a regulator. Maybe start with a resistor/zener as a reg. Then add an emitter-follower to buffer the zener…
Oh, and kinda late but welcome to the kicad forum!
Design for all of us means draw schematic and then design PCB. (KiCad is PCB design software).
Run circuit means have it done and power it. Simulation is not running circuit. It is only simulating circuit.
You clearly say here that goal is PCB. Designed and then etched (or ordered) PCB.
No doubts at this point about what you are planning to do.
So you are searching for transformer. Not simulation model but real transformer.
KiCad is a tool to design PCBs. So using KiCad is understood as designing PCB.
Simulation is only additional feature.
If you don’t care how dangerous it is it is your business. But every responsible person seeing that someone is trying to harm themselves tries to prevent it. And it looks like you suddenly have a grudge for people trying to protect you.
Here you mentioned simulation for the first time. But still you don’t say of drawing schematic and simulating it, but about building circuit and then simulating it.
You have to draw schematic. It is obvious. But then you want to build circuit as you write or only simulate it.
Should we trust what you write or assume that you are imprecise?
It sounds like you’re offended that people trust what you write.
You didn’t mention that up front. So the transformer in spice just needs the proper turns ratio. If you want 120VACrms in, and 12VACrms out, it is a 10:1 ratio, or for 9VACrms out a 13:1 ratio. Spice models for diodes and caps are standard. There are likely regulator models, I don’t know the details. Simulate varying load current and bulk cap affects the peaks and valleys of the Vunreg. You need a 60Hz 120VACrms (not peak or pp) sinusoidal source, transient simulation for a few hundred milliseconds (at 60 Hz each half cycle of the full-wave-rectified signal is 8.3ms). Then add a regulator. Maybe start with a resistor/zener as a reg. Then add an emitter-follower to buffer the zener…