Hello Everyone ,
I am asking if it is possible to someone design this circuit in kicad because I am having issue trying to set it up and run the circuit
This is about the simplest sort of project you can do in KiCad, and it is a good schematic to start to learn KiCad. Especially for beginners though I recommend to stay away, or at least be very careful with mains connected circuits. In this design you can keep the transformer off the PCB, and insulate it’s simple wiring with an extra layer of shrink wrap. Most transformers also need a fuse in the primary circuit for safety.
I am trying to recreate this pcb it just a phone charger adapter . I am having issue selecting the transformer and a ac voltage source in kicad
The AC in would be just some sort of connector in KiCad.
For the transformer, you can combine a generic symbol for a transformer, with a suitable footprint for an existing transformer. There are some 50+ transformer footprints in KiCad, and the footprint has to match with the actual transformer you want to use. The procedure is very similar to generic parts such as capacitors and resistors. KiCad only has a few schematic symbols for resistors, but there are many sizes of real world resistors. From small SMT resistors to big power resistors.
Also, is this a circuit for which you really want to make a PCB, or is it mostly for practicing with KiCad? Making such a power supply is a bit unusual these days. You can buy a ready made 5V USB power supply for less then the parts cost to make one yourself.
You can buy a wall wart for around $5US and probably not electrocute yourself in the process. I personally don’t see how you could do it better or cheaper yourself. If you want to learn electronics, this is not the place to start.
I’m not gonna close the thread, yet, but 230V mains and you have no idea even how to source the parts?
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Sounds much like a school spice assignment so we can do the homework. Seen these come up before.
And that pcb has two transformers, additional parts, and might even be a switcher.
Inexperienced folks messing with mains voltage, is, well, really just part of the natural selection process 
Yeah that looks like a switcher, probably puts out more current than the 7805, and it doesn’t look like it came from a phone charger. Anyway out of scope for KiCad forum.
My thoughts exactly, and I design switchers. Mains frequency (50/60 Hz) transformer-based power supplies are 98% obsolete. There may be some for cordless phone chargers for example.
My understanding is that wireless chargers don’t operate at 50/60 Hz but at 100 kHz and above.
But wireless chargers, if implemented incorrectly, are likely to behave as chargeless wirers. Those are most likely to operate at 0 Hz.
I hope the factory workers who sloppily sloshed all that hot glue around the board are not the same ones doing PCB assembly. 
I am EE intern, and I am attempting to design a circuit capable of converting a 120V AC input to a 3.3V DC output. The main challenge I’m encountering in KiCad is selecting the appropriate transformer for stepping down the voltage, after that I will implement a bridge rectifier to convert AC to DC, and integrating a voltage regulator to ensure the output does not exceed 3.3V.
So your story has changed? First it was 230VAC to 5VDC and for a mobile phone. Now it’s 120VAC to 3.3VDC? In any case it’s electronic design and very little to do with KiCad. This forum is about designing PCBs using KiCad.
You have a problems with it because KiCad is not the tool to select elements (including transformers). You should check the distributors offer of transformers and select one. Then in KiCad you can make/select appropriate symbol for it and make/select appropriate footprint for it.
Today supplies are made differently. You first rectify AC to DC (1000V diodes are one of the cheapest) and then you do DC/DC converter with little (cheap) transformer. Recently I have bought 3 LED lamp supplies (AC230V → DC12V, 24W) for $3 each.
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I think you are referring to Darwinian selection principles. Like the kid I saw years ago riding his bicycle, with two hands + 2 eyes on his phone and 0 hands on the handlebars.
SERIOUSLY: I have designed AC/DC switchers. Handling mains voltage is not for people who do not know what they are doing.
Well ok, if you really want to play with a circuit like this, here’s what I would do:
Get an ac-to-ac (not ac-to-dc) wall wart, like perhaps this one:
A 9VAC wall wart
This isolates and steps down the mains so you don’t get electrocuted, and this one puts out about 9VAC which I presume is rms (have not used a power transformer for decades). 9VACrms times square-root-of-two is a peak voltage of about 12.7 VDC – the bridge will full-wave rectify this and
you lose two diode voltage drops, then the first bulk filter cap after the bridge will smooth out the unregulated voltage to about 12.7-1.4 – let’s say about 11-ish VDC (unloaded).
So now you have about 11VDC to regulate down. The ancient lm7805 will get you down to 5V but there is a lot of loss as heat so you can’t draw too much current before the regulator get hot. Let’s say you load the 5V output with 50-ohms for 100mA of load current. The regulator has a drop of 11-5 = 6V across it, times 100mA is 0.6 watts of waste heat. This is not too bad for a TO-220 package, and a little clip-on heatsink helps, but you won’t want to draw 1 amp out of the regulator or it will dissipate 6 watts!
A better way to drop down to 5V is a buck switching regulator which is quite efficient (not much waste heat), and if you want to spend time learning electronics it is an interesting little circuit. You can design them with separate parts, or simply get one in a tidy little package like this:
buck reg in a box
Then add a little 3.3V low-drop-out (LDO) linear regulator like a TC1015-3.3 to get down to 3.3V
Don’t forget input and output caps on the regulators – read the data sheet.
Look guys, I come on this forum looking for help on how to use kicad. I dont care about how dangerous this is. I am just asking how to build this circuit in kicad and run some simulation to see how the circuit behaves when I change values. I just want to learn how to use the tool .
If you guys really don’t wanna help and just roast me, fine 
but atleast point me in the right direction for some documentation on how to change the parameters in the components so i can run simulations.
I am not asking for help on selecting the parts from distributors or how to engineer this pcb. I just want to recreate in Kidcad. Jeez
You first post didn’t give that impression at all. It set the tone for the rest of the conversation.
This is the first time you have mentioned simulation . . . look here for some good information:
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And this should help you with most of the rest of the information you need: https://docs.kicad.org/ 
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