An adapter configured to charge a mobile device, the adapter comprising: a power conversion unit, configured to convert input alternating current to obtain output voltage and an output current of the adapter, in which the output current of the adapter is a first current with a first pulsating waveform; a sampling and holding unit, coupled to the power conversion unit, and configured to sample the first current when the sampling and holding unit is in a sampling state, and to hold a peak value of the first current when the sampling and holding unit is in a holding state; a current collecting and controlling unit, coupled to the sampling and holding unit, and configured to determine whether the sampling and holding unit is in the holding state, and to collect the peak value of the first current held in the sampling and holding unit when the sampling and holding unit is in the holding state; a charging interface, and a voltage adjusting unit, coupled to the power conversion unit, and configured to detect and adjust the output voltage of the adapter; wherein the current collecting and controlling unit is coupled to the voltage adjusting unit, and configured to adjust the peak value of the first current via the voltage adjusting unit, and wherein the adapter is configured to directly apply the first current with the first pulsating waveform to a battery to be charged, characterized in that the first pulsating waveform is a pulsating waveform obtained by performing a peak clipping on a complete pulsating waveform, wherein peak clipping refers to filtering out a part of the pulsating waveform which exceeds a certain threshold to realize the control on the peak value of the first pulsating waveform. a power conversion unit, configured to convert input alternating current to obtain output voltage and an output current of the adapter, in which the output current of the adapter is a first current with a first pulsating waveform; a sampling and holding unit, coupled to the power conversion unit, and configured to sample the first current when the sampling and holding unit is in a sampling state, and to hold a peak value of the first current when the sampling and holding unit is in a holding state; a current collecting and controlling unit, coupled to the sampling and holding unit, and configured to determine whether the sampling and holding unit is in the holding state, and to collect the peak value of the first current held in the sampling and holding unit when the sampling and holding unit is in the holding state; a charging interface, and a voltage adjusting unit, coupled to the power conversion unit, and configured to detect and adjust the output voltage of the adapter; wherein the current collecting and controlling unit is coupled to the voltage adjusting unit, and configured to adjust the peak value of the first current via the voltage adjusting unit, and wherein the adapter is configured to directly apply the first current with the first pulsating waveform to a battery to be charged, characterized in that the first pulsating waveform is a pulsating waveform obtained by performing a peak clipping on a complete pulsating waveform, wherein peak clipping refers to filtering out a part of the pulsating waveform which exceeds a certain threshold to realize the control on the peak value of the first pulsating waveform.