What are the directions of compass N and S?

N on the compass stands for North, and S stands for South. In the invention of compass, there are three parts that indicate the direction physically, namely Sina, compass and magnetic needle, all of which belong to the invention of China. The earth is a big magnet. When the magnets on the earth's surface can rotate freely, they will indicate the north and south because of the nature that like magnets repel and opposite magnets attract.

Compass, called Sina in ancient times, is mainly composed of magnetic needles installed on the shaft. Under the action of natural geomagnetic field, the magnetic needle can rotate freely and keep in the tangential direction of magnetic meridian. The south pole of the magnetic needle points to the geographical south pole (magnetic north pole), and the direction can be distinguished by using this property.

In ancient China, the compass was first used for rituals, etiquette, military affairs and divination, and to determine the orientation when looking at geomantic omen. In modern times, compasses are often used in navigation, geodesy, travel and military affairs. As one of four great inventions of ancient china, the invention of compass has played an inestimable role in the development of human science and technology and civilization.

Modern people have made all kinds of electronic compasses. Smartphones generally have this software. Electronic compass, also known as digital compass, is a method to determine the North Pole by using geomagnetic field. When applied to a mobile phone, it is actually an electronic compass. An electronic compass generally consists of a magnetoresistive sensor and a fluxgate. Electronic compass can be divided into plane electronic compass and three-dimensional electronic compass. The plane electronic compass requires the user to keep the compass level when using it, otherwise, when the compass is tilted, it will also give the change of course, but in fact the course has not changed.