A power adapter, comprising: a first rectification unit, configured to rectify an input alternating current and output a voltage with a first pulsating waveform; a switch unit, configured to modulate the voltage with the first pulsating waveform according to a control signal; a transformer, configured to output a voltage with a second pulsating waveform according to the modulated voltage with the first pulsating waveform, wherein an end of a primary winding of the transformer is coupled to a first output end of the first rectification unit; a second rectification unit, configured to rectify the voltage with the second pulsating waveform and output a voltage with a third pulsating waveform; a first charging interface, coupled to the second rectification unit and configured to apply the voltage with the third pulsating waveform to a battery of a device through a second charging interface of the device when the first charging interface is coupled to the second charging interface, wherein the second charging interface is coupled to the battery; a control unit, coupled to the switch unit, and configured to output the control signal to the switch unit, adjust a duty ratio of the control signal, such that the voltage with the third pulsating waveform meets a charging requirement; a second voltage sampling unit, configured to sample the voltage with the first pulsating waveform to obtain a voltage sampling value; and a comparator unit, wherein a positive input end of the comparator unit is coupled to an output end of the second voltage sampling unit, a negative input end of the comparator unit is coupled to a reference voltage providing end, and the comparator unit is configured to compare the voltage sampling value and a reference voltage value to output a comparison signal and apply the comparison signal to the switch unit when the voltage sampling value is greater than the reference voltage value, so as to control the switch unit to forcibly open, wherein the first rectification unit is connected to the primary side of the transformer without electrolytic capacitor and the second rectification unit is connected to the secondary side of the transformer without electrolytic capacitor. a first rectification unit, configured to rectify an input alternating current and output a voltage with a first pulsating waveform; a switch unit, configured to modulate the voltage with the first pulsating waveform according to a control signal; a transformer, configured to output a voltage with a second pulsating waveform according to the modulated voltage with the first pulsating waveform, wherein an end of a primary winding of the transformer is coupled to a first output end of the first rectification unit; a second rectification unit, configured to rectify the voltage with the second pulsating waveform and output a voltage with a third pulsating waveform; a first charging interface, coupled to the second rectification unit and configured to apply the voltage with the third pulsating waveform to a battery of a device through a second charging interface of the device when the first charging interface is coupled to the second charging interface, wherein the second charging interface is coupled to the battery; a control unit, coupled to the switch unit, and configured to output the control signal to the switch unit, adjust a duty ratio of the control signal, such that the voltage with the third pulsating waveform meets a charging requirement; a second voltage sampling unit, configured to sample the voltage with the first pulsating waveform to obtain a voltage sampling value; and a comparator unit, wherein a positive input end of the comparator unit is coupled to an output end of the second voltage sampling unit, a negative input end of the comparator unit is coupled to a reference voltage providing end, and the comparator unit is configured to compare the voltage sampling value and a reference voltage value to output a comparison signal and apply the comparison signal to the switch unit when the voltage sampling value is greater than the reference voltage value, so as to control the switch unit to forcibly open, wherein the first rectification unit is connected to the primary side of the transformer without electrolytic capacitor and the second rectification unit is connected to the secondary side of the transformer without electrolytic capacitor.