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Where does the ground symbol come into play? Does Spice need one?

Yes.

I get the following error:
“Pin connected to other pins, but not driven by any pin”. Power input of
component #GND0101 is not driven (Net 10)

Kicad design rule checking requires that things that should be powered,
are powered. The output from a regulator will give it the information
it needs (because of the way the symbol is designed), but where the
power source is not clear (eg kicad doesn't know that you will be
connecting a circuit node to a power brick), you must tell it. This is
achieved with a power flag, which in PCBNew is stashed with the ground
symbols. It's a square box with a single pin that must be joined to
the powered circuit node.

Regards,

Robert.

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Where does the ground symbol come into play?? Does Spice need one?

Additional thoughts - if you mean "in general", as opposed to being
specifically for Spice, it's good practice to use it on any schematic
that has a circuit ground (which is pretty much all but utterly trivial
circuits), for the benefit of others reading your schematic. Think of
it as where you would connect the ground lead of a measurement
instrument (hence its use in Spice). Also, on a single schematic, all
circuit nodes connected to a ground symbol are assumed connected
together, even if that isn't made with an explicit connection (a green
"wire" in Kicad). Kicad will also make that assumption.

Note, however, that there are different grounds, such as circuit ground
and protective ground. These different grounds are not necessarily
connected together, but if they are, it will be done at a single point
(called a star point), and that connection will be explicit on the
schematic.

Regards,

Robert.

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The not driven error as mentioned is a ERC error. The design rules don't
know that you are powering the circuit externally. So you add a power
flag to tell the system that the net is actually powered, as Robert
described.

A big trap that beginners fall into is not knowing that the ground is
also considered a "powered" net. That usually means that you need to add
a Power flag onto the ground net as well.

You can only have ONE power flag or ONE device providing power on a net,
or things get even more confused.

Generally (because of the above) I do not like devices that specify pins
as power outs, and I edit them to remove that. I prefer to add power
flags and leave it at that.

Andy


On Tue, 5 Oct 2021 19:22:02 -0700
"Ken Cone" <kencone@...> wrote:

Hello,
I’m a new Kicad user trying to simulate a simple cap charge circuit with a DC source, a resistor, and a cap.

Where does the ground symbol come into play? Does Spice need one?

I’m using the pspice model for “0v reference potential for simulation”.

I get the following error:
“Pin connected to other pins, but not driven by any pin”. Power input of component #GND0101 is not driven (Net 10)
See enclosed screen shot. Thanks.


Ken Cone
kencone@...
K7BXI