I deleted all this and reposted as simpler question further below.
If you add 0R or ferryte bead or choke it also breaks it in sense you probably think of.
I have no such problems as I never run ERC.
But if you want it the solution is described here:
I do not understand your text.
What does “breaks the circuit” mean? At first I thought it twas the usual PWR_FLAG thing, but I guess you may mean something else.
Amazingly I watched though your 7 minute video. It did not explain anything (to me). Resolution is too low to read error messages.
Using a wire or a power symbol does not matter, but when you change the wire from:
To the power symbol in:
Then you change the actual connectivity of the schematic. Those netlists are not the same.
Sorry I deleted this post because I think I’m confusing the issue.
I’ll come back later as I also think I know what I’m doing wrong.
The key fact to be aware of is that KiCad’s ERC is not smart enough to know that a fuse is a piece of wire (until it blows, of course) and introducing it or removing it changes the circuit. With and without the fuse are different circuits. The layout doesn’t automatically rewire itself.
Same thing for 0R resistors, inductors and similar.
And it has always been so for all KiCad versions (that I know).
Sorry, but not for schematic and layout design purposes. It behaves identically to for example a resistor. And even for physical purposes it’s a resistor before it breaks, even though that’s not relevant here.
EDIT: I think you created a red herring for others by talking about pin types. It has nothing to do with your problem, you didn’t seem to use ERC.
Instead of posting video’s (tedious to watch) it’s better if you post some screenshots, and then explain in the text what are the important things in those screenshots. You can also use a simple pixel drawing program to emphasize some details in the screenshots.
Lets try again.
Question:
As in the screenshot, Where do I add a fuse for the +5V in this schematic whilst keeping both sections seperate and what should the pins be so that the circuit board does not error.
What fuse symbol? I don’t see a fuse symbol.
So is the fuse symbol, you intend adding, from a Kicad library?
Normal location of the fuse is between the input connector and “everything else”.
I do not see a connector for the input power on your PCB.
What is this:
Those are “MountingHole” symbols. Are you using them as placeholders for input connectors? Maybe for Banana Jacks?
If so, then use “MountingHole_Pad”. Then you can add them to the netlist, and assign a footprint big enough to mount Banana jacks into it.
Once you have a real input connector, you can put the fuse between the input power and the +5V power symbol.
Since you have connected the +5V label to two places, inserting in series with either one will not work, the other will still be connected to +5V.
You’ll have to connect +5V to one end of the fuse (and nowhere else), label the other end AFTERFUSE or something, and then connect both the power unit and the rest of circuit to this.
Think of the +5V power symbol as creating wires between every point to which it is attached.
There is a lot more cleanup that others have mentioned.
Could sombody please change my schem with a working fuse. Top and bottom diagrams kept seperate and when I update the Board it does not have unconnected wires and dead pins.
To simplify I’m asking you to fix it for me so that when I update the board it does not error.
Solder pads. Don’t worry about them they make no difference. I deleted them to simplify even more.
Can you please draw me a diagram?
Sorry. I have wasted to much time on this and have no idea what you are instructing everything is good as long as I don’t add a fuse. Adding a fuse no matter where or pin designation it always breaks the Boards net.
No!!! This is your whole problem.
A PCB does not work without power. You have to have a way to get power onto the PCB. You can solder wires to it, you can use a connector, or a battery (battery holder). But power has to come from somewhere.
So the real problem is that you have to realize that a connector (any connector, also the power input) is a real schematic symbol and it needs both the schematic symbol and the footprint.
So add something like this to your project:
NOTE TO ALL: Thanks for your attempts but I give up. After many hours on this and out of the circuits I’ve made over the years everything has worked perfectly as long as I don’t add a fuse. Kicad 4,5,6,7,8 I’ve made atleast 10 projects and dozens of variation attempts to add a fuse. I honestly don’t know why I even bothered trying again, it’s a simple F!!! fuse. Non the less it has been part resolved, Schem errors but Board is OK, even though I have already done same scenario and it failed. I’m done with it.
paulvdh I know all that but you’re missing the whole point, Everything is fine as long as I don’t add a Fuse. I got tired of trying to explain, I’m going onto 4 + hours of different variations to add simple F!!! fuse. That’s why I took things out and just asked for someone to fix it for me, I don’t care what’s wrong if some fix it I can replicate/revers engineer it.
See schem 1 > NO Fuse All Good:
Schem 2 > Fuse added ERC errors but this time around the board does not break. NOTE: I have done this way schem 2 and board breaks but not this time, so I’m done, Had enough leaving it like this.
Yes, I think I can do that for you, but I’m not going to redraw your whole circuit.
It is easier if you zip up your project, then I can make a modification and post it back.
But before I can do that, I need to know how you add power to the PCB.
Looking at your screenshot:
I do not see how to add wires to your PCB, and the fuse has to connect to the wire that is entering the PCB. Without that wire, I can not connect the fuse.
Here is a simplified schematic and PCB layout to illustrate what retiredfeline and Paulvdh are telling you, that you need a way for the +5V power to enter the PCB:
The KiCad project for the attached illustrations:
FUSE.zip (24.5 KB)
The attached project passes all ERC and DRC checks.
But you found the way to add resistors.
I see no difference between fuse and resistor. Both in THT and SMD they even can have the same footprint.
So as you know how to add resistor then I don’t understand why you don’t know how to add fuse.
When you add resistor on the wire it also breaks the connection and you have no problem with it so why you have a problem with the same effect of adding fuse.
I’m always curious how erroneous ways of thinking persist.
In this case I think it’s a failure to understand the nature of the +5V power symbol. It’s not a measurement. It cannot be reused for a different net even if that net also is at 5V due to zero resistance to the +5V net. It behaves like a label that joins up all points where it’s attached as if wires were used.
When a fuse, or a 0R resistor is used, then the input side, if it has to be labeled, should be called PowerSupply or something like that and +5V used for the protected side.
The issue here is that your power flag is on the input side of the fuse (assuming that the mounting hole is being used for power input). Move it to the side you’ve labelled +5v and all should be fine. To be clear - the output side of the fuse needs to connect to both +5v AND the power flag.
KiCad doesn’t know that the fuse connects nets - it can’t make arbitrary assumptions about connectivity between pins in symbols.
Issues with power flag was also our first guess in this thread. But later I had exactly the same feeling as eelik said:
Than the first problem description was deleted and current problem seems to be defined as “fuse breaks net”.
I think you hit the nail on the head here but it was already said in different words several times and we still don’t know if was understood.
I simply do not understand why OP searches for the difference between fuse and other elements like 0R, ferryte bead, choke.