Does pcb routing in Kicad follow the schematic that you have created in eschema?

Hi I’m new to Kicad, I created a schematic and then created the board in the pcb page. I noticed that when you start routing, it automatically shows wher it needs to go, so I just created the board by following the routing. I have noticed however that some of the circuits aren’t routed exactly how the schematic presents. I have especially noticed that the routing of a forward biased diode circuit tends to be incorrect, I.e the supply voltage through the diode anode through to cathode to stop back feed won’t connect this way. Instead it wants to connect to the cathode.

I’m nervous about spending hours creating the schematic, only for the pcb routing to undo the work, please take it easy, as I’m pretty new to it.
Appreciate the help,

Did you happen to use the spice model diodes in Kicad? I seem to remember spice likes them numbered reverse.

What sort of circuit are you designing? With many (or most) modern circuits, good layout is essential, and you need to understand what is important in that regard, or at least carefully follow some good guidance. Long story, but I remember when a layout designer laid out my power converter without any layout input from me (I was out of the country). This thing absolutely 100% did not work at all, even though there were no netlist errors. KiCad pcbnew will do as this layout designer did. It can direct you to connect everything to agree with the schematic netlist, but it cannot guide you to a good layout. The result is likely to work badly or not at all…

What version of KiCad are you using? Have used old versions before?
The diode pin/pad numbering issue belongs to V4 days

It will always stay a potential issue as long as spice is a thing. And it will of course stay an issue on packages like SOT-23 as nobody seems to be able to agree which pad numbering scheme to use.

@Greg_Faint as you state you are new you might be interested in this Tutorial: Introduction to PCB design with KiCad version 5.1 (Getting Started)

Thanks everyone for the advice.
The version I have is just the generic download that shows when you search for Kicad software. I more of less stumbled across it as I was searching for software to design and put into production circuit boards. I am an Auto Electrician, so the schematic itself is 100% correct ( I checked this all out incase I had stuffed up) but when I was double checking the pcb routing I noticed the issues that I mentioned. To be honest I’m not sure if I am using SPICE components, I am purely just going through the motions and using what the Kicad program has. I will check that link out with an introduction to Kicad. Thanks again for all your advice!!

Welcome @Greg_Faint,

You can find the Kicad version you are using by going to Help, About Kicad.
You can copy (at bottom of page) then paste into this forum if you wish.

Mapping schematic symbols to footprints is always a concern in any PCB program, and the underlying problem is the lack of standardization in the industry, and that is caused by lack of an authority that can mandate such standards, and I’m not even sure If I’d like such an authority…

The SOT-23 Rene mentioned is a classical example. There is not even agreement on where “pin 1” is on that package, so if you have similar parts from different manufacturers you always have to be cautious.

Have a look at the post from this poor guy:

It’s a year and 11 days now, and he still hasn’t gotten any answer.

Many experienced engineers have taken up the practice of using existing libraries, but never trusting any part of it, and manually checking and verifying each and every part of schematic symbols and footprints. This is a time consuming practice of course, and to reduce repetitive tasks, once a library part is verified, it is copied and saved in a personal library with with vetted parts. Parts from that library are trusted as being correct and used without further checking.

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