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 transformer; a second rectification unit, configured to rectify an output at a secondary side of the transformer to output a voltage with a third pulsating waveform, wherein the voltage with the third pulsating waveform is configured to be applied to a battery of a terminal; a sampling unit, configured to sample the voltage with the third pulsating waveform to obtain a voltage sampling value; and a modulating control unit, configured to modulate the voltage with the first pulsating waveform according to the voltage sampling value to obtain a modulated voltage with the first pulsating waveform, to apply the modulated voltage with the first pulsating waveform to a primary side of the transformer, wherein the transformer is configured to convert the modulated voltage with the first pulsating waveform into a voltage with a second pulsating waveform such that the voltage with the third pulsating waveform meets a charging requirement of the battery, wherein the first rectification unit is connected to the primary side of the transformer without electrolytic capacitor and the second rectification unit is configured to apply the third pulsating waveform without electrolytic capacitor, and characterized in that the power adapter further comprises a first charging interface; the power adapter is coupled to the terminal via the first charging interface to establish a bidirectional communication, and the modulating control unit is further configured to obtain status information of the terminal via the bidirectional communication between the power adapter and the terminal, and to modulate the voltage with the first pulsating waveform according to the voltage sampling value and the status information of the terminal, wherein the status information of the terminal comprises an electric quantity of the battery, a temperature of the battery, a voltage/current of the terminal, interface information of the terminal and information on path impedance of the terminal. a first rectification unit, configured to rectify an input alternating current and output a voltage with a first pulsating waveform; a transformer; a second rectification unit, configured to rectify an output at a secondary side of the transformer to output a voltage with a third pulsating waveform, wherein the voltage with the third pulsating waveform is configured to be applied to a battery of a terminal; a sampling unit, configured to sample the voltage with the third pulsating waveform to obtain a voltage sampling value; and a modulating control unit, configured to modulate the voltage with the first pulsating waveform according to the voltage sampling value to obtain a modulated voltage with the first pulsating waveform, to apply the modulated voltage with the first pulsating waveform to a primary side of the transformer, wherein the transformer is configured to convert the modulated voltage with the first pulsating waveform into a voltage with a second pulsating waveform such that the voltage with the third pulsating waveform meets a charging requirement of the battery, wherein the first rectification unit is connected to the primary side of the transformer without electrolytic capacitor and the second rectification unit is configured to apply the third pulsating waveform without electrolytic capacitor, and characterized in that the power adapter further comprises a first charging interface; the power adapter is coupled to the terminal via the first charging interface to establish a bidirectional communication, and the modulating control unit is further configured to obtain status information of the terminal via the bidirectional communication between the power adapter and the terminal, and to modulate the voltage with the first pulsating waveform according to the voltage sampling value and the status information of the terminal, wherein the status information of the terminal comprises an electric quantity of the battery, a temperature of the battery, a voltage/current of the terminal, interface information of the terminal and information on path impedance of the terminal.