Creating libs etc is very easy and moving things from one lib to another
is also easy. It's a task worth getting to know.
The EDR is not there to tell you that your design won't work, its to
ensure that your connection are all there.
I've never used the LTspice or Spice function of Kicad, but I do use LT
spice stand alone.
When I started, I did only one board with tape and dots.. Fortunately it
was a training exercise, and very shortly after we got an early PCB
layout system Racal Kadet I think. The layout techs would not let us
engineers near the thing, I think they thought (probably correctly) that
we would have it in bits to see what made it tick :-]
Andy
On Fri, 21 Jun 2024
22:10:37 +0100 "John Woodgate" <jmw@...> wrote:
I can accept all you say, but for my limited work I think that creating
new libraries is not justified. The point about the opamp is that the
EDR won't tell you that you have provided strong positive feedback
because you have not noticed that the + input is at the top. An .AC
might also not tell you, but a .TRAN would. My projects are now
'kitchen sink' - special test equipment, usually one-off, but when I
was in industry, 4000 would be a very modest run. In those days, it was
black tape on drafting film.
On 2024-06-21 21:46, Andy wrote:
Yes the pin positions are more common with -ive uppermost, but not
always.
The EDR cannot detect this because it in NOT an error it's just how
the symbol was drawn. It's down to the designer to connect the
components to the correct pin.
If you don't like it, then change the symbol...
I can't stand the American electrolytic symbol, so I change that to
the one that I've used for decades, the filled box for -ive and
unfilled for +ive
This highlights a VERY important point for ANY CAD system be it Kicad,
Eagle, Autocad, or any other design tool.
You NEVER use the provided symbols for live work. You ONLY use symbols
that you have checked and verified as good. These you save in your own
libraries and that's what you use when building your design on the
screen. It protects you from an unknown change being distributed to
the system that you don't spot, so when you use the part again you get
something different.
Not a problem on a single board "kitchen sink" project you just curse
at it, and bodge it. But if that happens on your 4000 board
production run you might be looking for a new job :-)
When you think about it, you only use a very small handful of
components in amateur projects so it does not take long to build up
your own libraries, and most of the provided ones will be perfectly
OK so it's just a matter of copying therm across to your own libs.
Andy
On Fri, 21 Jun 2024 16:04:18 +0100
"John Woodgate"<jmw@...> wrote:
As I understand it, I have to make a copy of the schematic and add
voltage sources (power and signal) and a load. Then add to that the
simulation command. But how do I introduce the models and subcircuits
for the active components?
What would be much easier for me is to be able to copy the schematic
into LTspice (as that is what I use) and do the simulation in that
environment. But is is possible to do that, i.e. can KiCad export a
schematic (or even a netlist) that SPICE understands?
This is important because it can be a costly mistake not to realise
that the KiCad opamp symbol has the + input uppermost, whereas it is
most common, I think, to see the - input uppermost. The EDR can't
detect that error, of course.
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Best wishes
John Woodgate, Rayleigh, Essex UK
Keep trying
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John Woodgate, Rayleigh, Essex UK
Keep trying
