Breaker

The utility model discloses a breaker, and aims to provide a breaker having a normally open mode and a normally closed mode. The breaker comprises a breaker housing, an operating mechanism, a conductor structure, an arc extinguishing device and a tripping device. The key points of the technical scheme are as following: the tripping device comprises a circuit module, an excitation coil, an elastic mechanism and a slide mechanism; the circuit module is electrically connected with the excitation coil; the slide mechanism comprises a slide rail, a pro-magnetic slide block capable of sliding along the slide rail and a contact piece which is in a linkage relationship with the slide block; the conductor structure comprises an input section and an output section which are separated by the slide block, and ends, which are relative to the slide block, of the input section and the output section are provided with contacts which are used to contact the contact piece to allow a conducting state to be achieved; and the sli