Abstract: An electronic appliance such as a digital audio disk player in which either an external power source, or a secondary cell is employed as a power source, includes a signal reproducing unit, a recharging unit, a judging unit, a measuring unit, and a controller. To the signal reproducing unit, an operation power source voltage is applied from the external power source, or the secondary cell. The voltage from the external power source is applied to the recharging unit so as to recharge the secondary cell. The judging unit judges whether or not the voltage from the secondary cell is applied to the signal reproducing unit. The measuring unit measures a time period during which the voltage from the secondary cell is applied to the signal reproducing unit when the judgement result obtained from the judging unit indicates that the voltage from the secondary cell is applied.