g 3 3v or 5v it is to be noted that a single dc power vd in fig2 is an illustrative example and is not to be construed as limiting the scope of the present invention in order to meet environmental friendly factors of energy conservation and carbon reduction the contactless switch of the invention is also designed to be power saving for example the ac dc converter 28 is controlled to output the dc power vd by an awake sleep cycle with a timing diagram as shown in fig3 in fig3 under an awake mode t1 the ac dc converter 28 outputs the dc power vd to provide an operating voltage to the magnetic sensor 22 the controller 24 the power switching module 26 and the communication module 30 in contrast under a sleep mode t2 the ac dc converter 28 is disabled with no dc power vd generated therefrom accordingly lower power dissipation to even no power dissipation is achieved under the sleep mode preferably the awake mode t1 and the sleep mode t2 alternate cyclically and the duration of the sleep mode t2 is far greater than that the awake mode t1 i e t2 gt gt t1 the magnetic trigger mechanism 20 first receives a user trigger and the magnetic sensor 22 operates in conjunction to sense the user trigger according to the contactless power switch 2 of the present disclosure the magnetic trigger mechanism 20 and the magnetic sensor 22 operate on magnetic basis through a magnetic signal 21 in fig2 i e there is no contact between the two and are.