Rotary switch having durable internal contacts

A rotary switch, comprising:

• a base comprising a shell and a circuit board received in the shell, the shell comprising an annular supporting portion inside the shell and above the circuit board, the supporting portion comprising a plurality of spaced first protrusions protruding on a top of the supporting portion, and defining a plurality of first indentations, each first indentation arranged in two neighboring first protrusions of the supporting portion, the circuit board comprising a plurality of contact pieces located on a top side of the circuit board, and arrayed in a shape of arc concentric with the supporting portion, each of the contact pieces aligning with one of the first indentations of the supporting portion;
• a rotary mechanism accommodated in the shell and comprising a rotary pole arranged above the supporting portion, a connecting member arranged above the rotary pole and slidably connected to the rotary pole, an abutting pole extending from an end of the rotary pole, and a first resilient member connected between the connecting member and the rotary pole to bias the rotary pole towards the circuit board, the rotary pole comprising a trigger attached to a bottom of the rotary pole, and aligning with the arc-arrayed contact pieces;
• and
• a manipulation member mounted to a top of the shell and fixed to the connecting member.