Understanding PCB's

[miko oyo]

Hi everyone!
First of all, I want to say that maybe there should be a section for this : questions about electronics by begginers, it's not really about a stompbox, it's really about understanding (I know there's the FAQ and wiki but it seems more like "old archives" to me). Anyway!

There's something I don't get with PCB's.
I totally understand this one :


But I get lost when I come to this :

I get the "wiring" and everything but in the schematics, R1 (1M) goes to ground, so does R2 (100K) and so on...
I really can't see how this is done on the PCB layout Can someone explain that (probably obvious ) thing to me?
Thanks a lot!

[Ripthorn]

It is simply an incomplete layout as far as I can see.  It is just missing some traces for ground.

[mth5044]

I'm not sure I get your question. How do you understand the first layout when the second one is the same thing (not circuit wise, I don't think, didn't really analyize it) just with different color traces. Maybe what you don't understand is that the clear part of the second one is a ground plane? See how the one end of R1 goes out and looks like it goes no where? That is why I assume there is a giant ground plane instead of the ground trace like the first layout.

Can you reformat your question? I don't quite understand

[miko oyo]

Yeah, exactly!
I didn't know that.
So if I read you well, it's all grounded and you just wire the GND to your jack (as in other circuits)?

[tref_h]

I don't think so (quite) -

I've only had a cursory look at the layout vs schematic, but I notice that you have round and square pads on the layout, and generally the square pads are grounded out, maybe the square bads are to be bridged or there is more than one conductive layer?  The other obvious thing I note is that the layout has outs for two pots, and only one seems to be noted on the schematic.  Without drawing a schematic from the layout I wouldn't like to say if the schematic is incomplete, for a different circuit that looks similar or I'm just going blind! ^_^

[Ripthorn]

Yep, that is a ground plane now that I look at it.  Never seen one quite like that before.  Seems like it would be hard to make an etch of that from the given layout.  I thought the ground pad was the diode anode pad, thus my comment about a possibly incomplete layout.

[alanlan]

Looks a bit like an Eagle layout.  In Eagle, the ground plane isn't flooded when you open up the PCB layout - you have to do something, although I can't remember exactly what - to flood the plane.  Possibly why it looks incomplete.

[Tony Forestiere]

Run the "Ratsnest" command pointing to GND in the command line.

[miko oyo]

Ok I see, it seems that layout is incomplete or something. That makes me feel a bit better.
I'll try to see if I can get anything more with Eagle,
thanks everyone!