There are three basic forms of relay contacts:
1. When the moving type (normally open) (H type) coil is not energized, the two contacts are disconnected. After energization, the two contacts are closed. It is represented by the pinyin head "H" of the word.
2. When the breaking type (normally closed) (D type) coil is not energized, the two contacts are closed, and the two contacts are disconnected after energization. It is represented by the pinyin head "D" of the hyphenation.
3. Conversion type (Z type) This is the contact type. This contact group has three contacts, that is, the middle is a moving contact, and one of the upper and lower static contacts. When the coil is not energized, the movable contact and one of the static contacts are opened and the other is closed. After the coil is energized, the movable contact moves, so that the original disconnection is closed, and the original closed state is turned off, and the conversion is achieved. purpose. Such a set of contacts is called a changeover contact. It is represented by the pinyin head "z" of the word "turn".