A power on and off testing device includes a control module, a switch module, an alternating current and direct current converter module, an input module, and a detecting module. The ice maker includes an ice making unit that receives water and produces ice from the water, a first ice container that receives the ice separated from the ice making unit, and an ice forwarding unit disposed at one side of the first ice container to guide the ice to be discharged to the outside. A phase inversion signal indicates the existence of a 180 degree phase difference between the first clock signal and a second clock signal. With this arrangement, it is possible to provide a more compact liquid crystal optical element than has been conventionally available. An output network pulls the analog output node to the \u201czero\u201d potential when currents applied to the intermediate nodes are directed to ground.