Negative voltages/power representation

Sorry if this is obvious, but as a complete beginner to Kicad, and schematics in general (and with no-one to ask in the office who all use Cadence), I have a job to do where I have +ve voltages, GND and -ve voltages. How do I represent the -ve voltage - the power sections don’t have anything for -VCC, and it’s not editable if I use the standard VCC and want to change it.

Now, it’s possible I am going about this entirely the wrong way - but some background, the board need to take positive AND negative from a power supply, with GND coming from something else it is attached to, so I cannot just use VCC and GND, I need that -ve input as well.

James

Why are you using Kicad if all your coworkers use Cadence?

-VE or -VCC or +VCC or whatever are just nets, you can use a special power symbol or a Global Label with the correct name (then attach a PWR_FLAG to it to make DRC happy). There are a few negative power supply flags in the “power.lib” Kicad library, though they’re specific (-5V, -3.3V, etc.). It would probably be helpful to use one of those that matches your -VCC to avoid ambiguity.

I thought the Cadence thing would come up! The stuff I will be working on will be open source, so using an open source/free design system was thought to be the best way to make it available to everyone.

Thanks for the voltage info, that makes it clearer! Like I said, very much a beginner at this, software is usually my thing…

James

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Feel free to ask/search here, the community is usually very helpful.

Just make your own symbol.
(By the way a power symbol is nothing else than just a global label. It does nothing else.)
It does not even give you a pwr flag. In fact it needs to be connected to something defined as a power output. (a pwr flag gives you this power output type.)

The easiest way to create a custom power symbol is by copying one of the standard symbols.
(-12VA for example)
Give it the symbol name of your liking.
Set the pin name to be the same.
And set the value field to be the same.

In the symbol properties field make sure define as power symbol is set.

Pin properties: use your desired net name as pin name. (use this name also for the value and for the symbol name)
Make sure the pin is set to power input and hidden.

The fields should look like folows:
reference: #PWR (invisible)
value: same as pinname:

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Wow, very comprehensive answer, thank you! Learnt quite a lot since I started on this…it seems like only yesterday…oh, it was…!