Can someone explain what MINUS 12 volts supplied by a power unit is all about?

Hi, yeah...i'm sure this question is super-ignorant, ultra-beginner level, and i'm showing my drastically limited understanding of electrical devices...but here goes

Why does my power supply module (which is the uZeuz power unit of the Tiptop Happy Ending 19" rack kit, but I presume this applies to many such units) have one supply for ribbon cable that is +12v and another for -minus 12v

I'm powering my modules off the + 12v, but can someone explain what the minus - 12 v is all about, and what that would be used for?

thanks T

In electrical circuits you always have a +Plus and a -Minus, think of it as turning on a light swtch to join the two and you get light.
Connecting your power cables the correct way around is important.

Older thread discussing -12, 0 & 12V

Thanks, also noting that Doepfer modules probably don't have reverse polarity protection, so i've probably been lucky (nothing blown at this point)