Maintained by the rotary switch is a mechanical, rotary switch, transfer, contact work;

Knob switch also called rotating switch, it of principle is can using a resistance of regulation problem, to solution we life in the of some regulation problem, it is divided into single very and multipolar two species form, so on caused has it can role of place has without, many of this switch in we life in the only can for a changes, or is for a document bit of regulation, but multipolar of on can for multiple document bit of changes, let we has different of experience. May say that we don't understand very well, as simple as an example is that we usually use electric fans, when we use it can be fast or slow adjustment, this is depending on the stall speed, use this principle.