A socket is further connected to the base circuit board 101, and a base connecting hole 115 for communicating with the base circuit board 101 is further provided on the base shell 100, so as to be connected with an external wire, and a base dust cover 104 for covering the base connecting hole 115 is snap fixed to the base shell 100.

A button welded on the base circuit board 101 is matched with the base button 108, and the base shell 100 is provided with a base sliding hole 117 for sliding and limiting the base button 108. The base shell 100 is provided with a heat dissipating hole 118 for communicating with the outside, thereby improving the internal heat dissipation capability.

Base bottom sheets 105 are symmetrically mounted on one side of the base shell 100 close to a plane for placement, the base bottom sheet 105 is disposed on one side of the base shell 100 away from the end cap assembly 4, and a base slot 116 for inserting the base bottom sheet 105 is disposed on the base shell 100. Base snap rings 106 are symmetrically disposed on one side of the base bottom sheet 105 close to the base shell 100, and a base snap block 107 snap-fitted with the base snap ring 106 is integrally disposed on the base shell 100. After the two are pre-fixed and snapped, the two are further fixed by bolts, thereby improving the overall stability.