Positive and Negative
In DC circuits, the positive pole is usually marked red (or "+") and the negative pole is usually marked black (or "-"), but other color schemes are sometimes used in automotive and telecommunications systems. On a car battery, the positive pole usually has a larger diameter than the negative pole.
In AC systems which are at no point connected to earth (unlike domestic mains wiring where the neutral is commonly earthed at substations and generators) polarity is not important as the two wires alternate polarity many times per second.
Read more about this topic: Electrical Polarity
Famous quotes containing the words positive and/or negative:
“Men just don’t “get” that the reason to become involved is for ourselves. Doing more with our children won’t simply make women happier or keep them “off our backs,” but will create a deeper, more positive connection with the kids.”
—Ron Taffel (20th century)
“A negative judgment gives you more satisfaction than praise, provided it smacks of jealousy.”
—Jean Baudrillard (b. 1929)