Some embodiments of the present invention provide a charger. According to the charger, a detection signal generation circuit actively sends a detection signal; a feedback circuit detects level signals on a sampling component, and generates a feedback signal according to the level signals; a switch component controls, according to the feedback signal, the charger to output a charging voltage; and when the level signals meet a preset condition (the preset condition is a preset condition that the level signals meet when an abnormal short circuit occurs on a charging interface), the switch component controls the charger to stop outputting the charging voltage.