Abstract: A protective circuit for a supersonic humidifier includes a compare circuit to obtain working voltage at two terminals of an ultrasonic vibrating member to decide whether the humidifier is to be continued to operate or stopped so as to protect it from burning up. The protective circuit does not utilize a vibration needle, a float, a magnetic switch and a HALL IC used in conventional humidifiers.

Abstract: An electric fan capable to rotate for 360 degrees includes a control device consisting of a left and a right shell combined together. The shells have a L-shaped steel plate inside to fix a motor and a speed-reducing device. The speed-reducing device has its spindle fitted with the fixed shaft of a clutch having bead hole for receiving two steel beads and a spring. A shaft sleeve has bead grooves for receiving two aforesaid steel beads and firmly fitted in a copper sleeve by a bolt screwing through a bolthole and resting against a concave groove of the stand post. The shells further have a shaft groove for receiving the upper half portion of the stand post, thus, the upper half portion is actuated by the control device to rotate with an angle from 0 degree to 360 degrees.

Abstract: An electric fan capable to rotate for 360 degrees includes a control device consisting of a left and a right shell combined together. The shells have a L-shaped steel plate inside to fix a motor and a speed-reducing device. The speed-reducing device has its spindle fitted with the fixed shaft of a clutch having bead hole for receiving two steel beads and a spring. A shaft sleeve has bead grooves for receiving two aforesaid steel beads and firmly fitted in a copper sleeve by a bolt screwing through a bolthole and resting against a concave groove of the stand post. The shells further have a shaft groove for receiving the upper half portion of the stand post, thus, the upper half portion is actuated by the control device to rotate with an angle from 0 degree to 360 degrees.

Abstract: A protective circuit for a supersonic humidifier includes a compare circuit to obtain working voltage at two terminals of an oscillator to decide whether the humidifier is to be continued to operate or stopped so as to protect it from burning up. The protective circuit does not utilize a vibration needle, a float, a magnetic switch and a HALL IC used in conventional humidifiers.

Abstract: A humidifier includes a float positioned at a water outlet of a water tank, and a body containing a water level sensor functioning with the float rising and falling with the level of the water in a water chamber in the body to drive the water level sensor in case of the water level falling to the lowest to turn off the humidifier. Then the water tank is simplified in its structure and making the humidifier safe to use.