Split into 3 seperate board from the same design

[Docara]

@paulvdh

I think you are being unnecessarily harsh and over critical for no reason!

Th OP was asking a perfectly reasonable question for a beginner (and to Kicad) and was being polite. There are better ways to convey criticism which is not belittling.

I found your wording quite rude surely impacting their confidence - why would they return here after your comment.

[RaptorUK]

@Docara

why would they return here after your comment.

Because the OP found Paul’s answer helpful . . .

@golkit1

Thanks this worked great!

[joojala]

Okay, so the reason auto routing does not solve your pcb design problems is simply that the routing is not the hard part, it is often pretty straight forward thing once you get the component laid out in a sane way its usually pretty easy to do the routing.

Let’s take some examples on your board. Look at R2 and R1. Consider what would happen:

• If R1 would be above R2
• and R and R2 would be rotated 180 degrees.

Now do this for all components. The trick is to postpone routing a bit longer until the layout is easier. Work form most important to least important…

[golkit1]

@joojala

Work form most important to least important…

what is most important and what is less important?
usually you start with closer components tracks then farther once?

[paulvdh]

@golkit1

what is most important and what is less important?

For some circuits, track length and loop area can be extremely important. (SMPS circuits is a good example).

For other circuits, (High impedance stuff) guard rings may be a necessity.

For other circuits, track resistance, and even minute voltage drops over tracks can be extremely important. A good example of this is PCB design for an audio amplifier. With a 120dB or more range between the output and the noise floor, and the presence of tracks that carry several amperes these things need special considerations.

For high speed logic, you get things like differential pairs and delay matching.

And of course, decoupling and their capacitors. And not only digital circuits need decoupling, it improves performance of analog circuits just as well.

And any PCB should at least give some consideration to EMC issues, and by far the simplest and straight forward method to do this is to design a proper GND plane into the circuit, especially because you get the 2nd layer for free with the cheap PCB pooling services. Rick Hartley has made an excellent (2h and 10 minute) video about “how to design a proper ground plane”. The video is worth the time, but I guess you’re not ready for it yet. But it does indicate the importance of this part of PCB design.

@joojala

Okay, so the reason auto routing does not solve your pcb design problems is simply that the routing is not the hard part, it is often pretty straight forward thing once you get the component laid out in a sane way its usually pretty easy to do the routing.

Yes. Already mentioned a few times in this thread, but still worth repeating. It is also one of the reasons why many people do not use an autorouter in the first place. Figuring out a good footprint placement needs a lot of attention to the details of which pins of your footprint connect together. And often you draw a few PCB tracks, then saw you made a mistake, move a few footprints and redo a few tracks. This is an interactive process by switching between a bit of track layout and footprint placement. An autorouter can not help here.

@golkit1

what is most important and what is less important?

High impedance stuff and signals are the most obvious. Keep sensitive parts physically separated from “noise generating” parts. Building circuits on breadboards is a good way to get an idea of the importance of signal integrity.

And overall, the big picture… You need to build up some experience, and to gain that experience you need to invest time. Autorouters can be a useful tool, but they are certainly not a magic tool that designs the PCB for you. This is a common misconception for beginners. And you do not gain much experience by using an autorouter either. It’s probably best to not even attempt to use an autorouter before you have routed around 20 or so PCB’s manually.

[svgeesus]

Having a GND plane is not about making routing easier (although it does). More on that here:

Beginner Question: Do I need copper fill if the PCB has no GND?

It’s correct that the bridge itself will work just fine without a GND plane. In the previous century GND planes were very rare (even for digital designs). So there is about 50 years of PCB design without GND planes, and before that point to point wiring (but that was often in a shielded metal box. Maybe by design, maybe by coincidence). One of the big reasons for using GND planes these days is because of EMC regulations. Not so important for a hobbyist, but mandatory for all commercial products…

Most designs will benefit from a ground plane because individual tracks have non-negligible resistance and thus (by Ohm’s law, V = IR) voltage drops between the different points. You want all GND connections to have the same potential and that is easier to achieve if there is a single ground plane with as few interruptions as possible.