Abstract: A pressure sensitive pen is provided. The pressure sensitive pen comprises a core body, an elastic element, a first magnetic body having one coil formed of at least a wire wound around, a second magnetic body, a sliding member, a hollow cylindrical body with an annular element formed therein and an inductance-capacitance type resonant circuit. The resonant circuit is electrically connected with the first magnetic body having the coil wound around. When a force is upward applied on the core body, the force is further applied on the sliding member through the core body such that the sliding member in conjunction with the second magnetic body move upward and make the elastic element deformed, and changing a predetermined distance between the first magnetic body and the second magnetic body, thereby changing an inductance generated by the coil, and the resonance frequency of the resonant circuit is thus changed.

Abstract: A pressure sensitive pen is provided. The pressure sensitive pen comprises a core body, an elastic element, a first magnetic body having one coil formed of at least a wire wound around, a second magnetic body, a sliding member, a hollow cylindrical body with an annular element formed therein and an inductance-capacitance type resonant circuit. The resonant circuit is electrically connected with the first magnetic body having the coil wound around. When a force is upward applied on the core body, the force is further applied on the sliding member through the core body such that the sliding member in conjugation with the second magnetic body move upward and make the elastic element deformed, and changing a predetermined distance between the first magnetic body and the second magnetic body, thereby changing an inductance generated by the coil, and the resonance frequency of the resonant circuit is thus changed.

Abstract: A power switch apparatus of universal serial bus device for protecting the universal serial bus device from electrical interference between a bus power mode and external power mode comprises a slide switch and socket door. The slide switch encased in the universal serial bus device selects either the bus power mode or the external power mode to serve as a unique power resource of the universal serial bus device by turning a control rod of the slide switch. The socket door assembled on the universal serial bus device has a pair of flanges protruding from an inner side of the socket door. The flanges is set at two sides of the control rod to turn the control rod to select the slide switch between the bus power mode and the external power mode, thereby preventing the universal serial bus device from the electrical interference.