1. The speaker has two terminals (two leads). When a single speaker is used, the two pins do not have positive and negative polarity. When multiple speakers are used at the same time, the two pins have polarity.

2. The speaker has a paper basin. Its color is usually black or white.
3. The shapes of speakers include round, square and oval.
4. The back of the speaker paper basin is a magnet. When the external magnetic speaker contacts the magnet with a metal screwdriver, it will feel the existence of magnetism; There is no such feeling in the internal magnetic speaker, but there is a magnet inside the shell.
5. The loudspeaker is installed on the machine panel or in the speaker box.