In a.c we use the terms common and neutral instead of positive and negativePlz explain
The longer answer is correct. AC is called alternating, because it switches from positive to negative 120 times per second, so it would be confusing to call either wire negative, so we call it common or ground. Earth in some countries. The hot wire is the one that will give you an electrical burn, or shock if you touch it or sparks if you touch it to something grounded. Common, and hot can be applied to either ac or dc, most most often to ac. Occasionally we find a dc circuit where the the command ground are positive. Neil
AC is Alternating current and does not have a negative and a Positive just a hot and a common.
Imagine the AC coming out of a nearby power transformer to your home. If the leads were left floating, it would be possible for a very high voltage to accumulate on either wire as it relates to the Earth you may be standing on. And you could be shocked. Besides, it could also cause a lot of ion migration of metals in your home (galvanic corrosion/electrolysis.) So one side is grounded at the transformer, by driving a copper stake into the ground or burying iron in cement (Ufer ground) that remains in contact with the ground. In this way, the hot side cannot be more than a hundred volts (or two) above or below the ground/common/neutral. And this helps reduce corrosion and helps reduce the chances of a high voltage spark igniting something. Obviously, it provides a galvanic connection in the Earth and that presents a shock hazard with the hot wire. But that, at least, is a predictable situation and manageable. Also, once the power is bought over to the home or business, the same 'side' is once again grounded into the Earth. This ties both sides and helps keep the voltage difference per foot of ground between the home and the power transformer to a minimum, as well. Hot usually just means the side that isn't connected directly into the nearby Earth's surface. One side is nailed down to Earth, so to speak, and the other side is left to 'wander' to one side or the other of that. Even so, being anywhere _near_ a huge smelter furnace used in steel making can lead to huge circulating currents in the Earth and this may develop large voltages that can corrode metal, including copper bus bars, surprisingly quickly.
