Hello Sirs,
I have some problems.I have a transistor BFP 420,which I use it in a electric schematic,all connections are all right from all terminals with all components,but when I run PCBnew to layout printed circuit,I can not to route the track from emitor of BFP 420 to resistor R4,does not appear that wire from emitter.I will attach some pictures below
And the second problem is that when I use the module Electrical rules checker tell me some errors that pins are not connected from that transitor BFP 420,and others components,but all connections are okay.I will attach a picture below.
The small green squares indicate that the wire is not really connected to the pin of your transistor symbol. In your particular case this is because the pins in your symbol are rotated the wrong way round. The connection point is marked with the small red circle that is pointed to by the ERC marker.
Every pin in KiCad really is a zero size entity with a graphical line attached. The small circle indicates where the pin really is. The line that you see is just for making it look nice.
Your transistor symbol is made in a way where the pin is located where the arrows point to (The green ERC error arrows in your screenshot). I suspect you want the pins to be where the wire has its endpoint (indicated by the green square). To achieve this open the symbol in the symbol editor and rotate the pins that are rotated in the wrong direction (and possibly move them as well).
I try again to run PCBnew to layout printed circuit,I can not to route the track from emitor of BFP 420 to resistor R4,does not appear that wire from emitter.I will attach some pictures below.Looking in Edit Symbol and Edit Footprint,it seems it is okay.
Well does ERC still report the same problem? (no need to look at pcbnew until this ERC error is gone!)
Does the symbol in your schematic actually look the same as the one you show in the symbol editor (take special note where eeschema shows the circles)?
If not check if you edited the correct symbol and possibly restart eeschema for it to reread the library state (make sure you do not select to rescue the symbol as you otherwise tell KiCad that you still want the old symbol). And check that you actually saved the changed symbol.
Also check that your schematic does point to the library you expect it to point to. (Do you have a local lib of the same name? Is it possible the symbol is taken from the rescue lib?)
You are probably also bitten by the most common error in KiCad.
Eeschema has no snap function to align wires with pin attachment points, and instead relies on coordinates to match up perfectly.
To do that easily, all symbols in all KiCad libs are aligned on the same grid, and you should never change the grid.
I’m a metric guy by heart, but in Eeschema I leave the units on inches, because that is what all schematic library symbols use.
When looking closer at your screenshots, I see that your pins are defined “backwards”.
The ring of the attachment points is on the inside at the location of the Emitters of your transistors. These points should be on the outside of the transistor.
Your solution is to open your BFP420 transistor in the symbol editor and reverse the direction of these pins. Also make sure that all pin attachment points are aligned on a “50” grid. The grid is in “in”, and not in “mm”, but in my head it’s just a nameless unit that should not be changed.
