/diy/ - Do It Yourself

Put all the blacks in a wire nut and pig tail to the always on gold screw (top). Break the tab with needle nose.

Put all the whites in a wire nut and pigtail to the silver screw side, either screw. Don't break the tab.

Put the white wire with black tape on the bottom gold screw. Make sure the tab is broken off.

Twist all the bare copper grounds together and connect the longest one to the recepticle

>>1698538
I am a beginner in electronics and I have dumb question that I could not get an answer with googling.
Why do some electronics (like small power supplies, in this case a for a servo) still have - and + terminals for voltage output instead of Vout and Ground? What use is there in + and - polarity in electronics outside making sure regular people put their batteries in the right orientation?