Structural characteristics of rotary switches

Common band switches and multimeter shift switches are rotary switches. There are two structures: one is the BBM (Break Before Make) contact type, which is characterized by the fact that the moving contact first disconnects the front contact and then connects the rear contact when changing positions, and there is a state of disconnection with both the front and rear contacts in the meantime: the other is the MBB (Make Before Break) contact type, which is characterized by the fact that the moving contact has a state of contact with both the front and rear contacts when changing positions. Then the front contact is disconnected and the contact with the rear contact is maintained. In circuit design, the appropriate rotary switch should be selected according to the circuit purpose and circuit safety.