Comparing schematic and PCB design

Thread Starter

RG23

Joined Dec 6, 2010
304
I have multiple PCB files all related to the same schematic but not all are the same.
How to confirm which PCB design is corresponding to the actual schematic?
 

dl324

Joined Mar 30, 2015
16,788
Do the boards and schematic have a revision number? They should...

If no revision info on the board, visually inspect (I know it could be tedious) and compare differences.
 

crutschow

Joined Mar 14, 2008
34,201
Compare the boards to see if you can spot the physical differences in the layout or traces.
You might want to print the layers on clear film so you can overlay them for ease of comparison.

Once you spot the differences, then you should be able to determine which one corresponds to the schematic.
 

JWHassler

Joined Sep 25, 2013
306
PCB layouts can be visibly different and yet still implement the same schematic.
Look at the time-stamps of the PCB-files as a first cut.
 

djsfantasi

Joined Apr 11, 2010
9,155
As mentioned, PCB layouts can be visibly different, yet implement the same schematic. Take a look at these two PCB board designs. They are designed from the same schematic. (Ignore the strip in the second picture)

 

Roderick Young

Joined Feb 22, 2015
408
One layout has a 4.7k SIP (resistor network in one package), and the other has separate 4.7k resistors. Check the schematic to see which one you want.
 

pwdixon

Joined Oct 11, 2012
488
One layout has a 4.7k SIP (resistor network in one package), and the other has separate 4.7k resistors. Check the schematic to see which one you want.
That was an example of the same schematic different layout, I don't think it was the circuit the OP was referring to.
 

dl324

Joined Mar 30, 2015
16,788
I would point out that there is no guarantee that the most recent version of the PCB file will correspond to the most recent version of the schematic file. Either could be revised independently. For example, in Eagle schematic changes can cause PCB routes to be removed; but I don't have to save the changed PCB. In that case, latest PCB does not correspond to latest schematic.
 
Last edited:

Stuntman

Joined Mar 28, 2011
222
Can you find the project file? That should let you know which PCB files are associated with that schematic.

If you wanted, you could make a new project, add the "correct" schematic file, then all the PCB files you think may be associated.

Open the schematic, under the Design tab, you can update each of the PCB files with the schematic on hand. Depending on your settings, you should be prompted of all the changes without actually having to make them. The one with no changes (or simply adding rooms or other garbage) should be ready to roll.... or you may find one that can be easily modified to your needs.
 
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