Abstract: A dryer having a filter sensing system that warns a user that a filter requires servicing. The dryer includes a drum that retains laundry. Hot air is drawn through the drum (for drying) and out an exhaust casing having a filter for removing lint and other particles. The temperature difference of the air in front of the filter (on the drum side) and behind the filter is determined using temperature sensors. When that temperature difference exceeds a predetermine threshold a control unit causes a notice unit to produce a warning signal that informs a user that filter service is required.

Abstract: A device and method for controlling a heater of a drying machine is disclosed, which includes a plurality of switches, each switch having a plurality of input terminals being supplied with different input voltages and an output terminal, and each switch connecting any one of the input terminals with the output terminal according to a switching control signal, and a heater connected to the output terminal of each switch and varying its temperature according to the input voltage being supplied thereto.

Abstract: Damping device in a microwave oven including an air duct on an electrical compartment side of a partition wall for guiding an air flow from a cooing fan to a cooking chamber, a damper rotatably hinged on the air duct for selectively blocking the air duct, a driving cam having a relative thickness difference between a thick portion and a thin portion, rotatable in contact with one end of the damper for pressing the one end of the damper to rotate the damper centered on the hinge owing to the thickness difference, and control means for controlling rotation of the driving cam, thereby providing a smooth damping operation, reducing a device cost, and preventing the microswitch from being pressed excessively.

Abstract: Damping device in a microwave oven including an air duct on an electrical compartment side of a partition wall for guiding an air flow from a cooing fan to a cooking chamber, a damper rotatably hinged on the air duct for selectively blocking the air duct, a driving cam having a relative thickness difference between a thick portion and a thin portion, rotatable in contact with one end of the damper for pressing the one end of the damper to rotate the damper centered on the hinge owing to the thickness difference, and control means for controlling rotation of the driving cam, thereby providing a smooth damping operation, reducing a device cost, and preventing the microswitch from being pressed excessively.