Newbire to KiCAD, add external VR and transistor to PCB while retaining symol in schematic

Layout
1

Sorry to ask this, but google search results are not what I need.

I have created my schematic OK, no issue, I have all of my components on the PCB OK, but two of them a potentiometer and a TO-3 power transistor need to be mounterd off of the PCB. How to I do this and retain them in their current positions within the schematic?

I know it probably has a lot to do with footprints, but that subject gives me a headache.

Any help or pointers appreciated.

Thanks in advance.

Rob

2

Not sure what version you are on but try editing the component in the schematic and enable “Exclude from board”

This will allow you to have the symbol on the schematic, but will not populate it on the PCB

image

3

This has been a question in my mind, too. Would it make sense to replace the two components with connectors with the appropriate number of pins?

I’m trying to get my head around what “Exclude from board” actually means. If the component is marked thus, what happens to the tracks that would normally connect to it?

4

Give those symbols footprints of the connectors or solder pads that will be used to connect them to the board.

It’s like the component wasn’t placed on the board at all so no ratsnest lines, no tracks to create.

5

I have never tried it and can’t check it now but probably tracks to not populated element just not exists.

KiCad project is the PCB project. If something is out of PCB it generally not belongs to PCB.
If potentiometer and transistor are expected to be connected in some way to PCB than you probably need pads to allow for that connection and these pads belong to PCB project. You should have them at schematic and correct footprints for them at PCB.

1 Like
6

Thanks. So, to check, if a component that exists in the schematic should not be mounted on the board, you would not mark it ‘Exclude from board’ because in that case there would be no pads to connect its wires to. Rather, you should give it a footprint of a connector or a footprint comprising solder pads. That way the pads will be connected into the rest of the circuit and the off-board component’s wires can be soldered to them.

Is that right? If so, what is the purpose of ‘Exclude from board’?

7

Various reasons. One may be that you want it in the schematic for simulation. It’s too late for me to come up with others. Have fun.

8

I place a connector, both plug and socket, together with the pot on the schematic. I then mark the plug and the pot as “exclude from board”.

I then have only the socket and its pads on the PCB. The plug, pot and connecting wires do not show for the PCB.

9

Ah, thank you, @jmk, that make perfect sense. It’s obvious once it’s been explained! :sweat_smile: