Did you ever felt, that one Charger/USB cable set charges your device really fast and the other not? Now, you can prove this with Ampere.Start the app and wait ca. 10 seconds (“measuring” is on the display). After this time, the charging or discharging current will be shown.The app measures the charging/discharging current of the battery. If your phone is not connected to a charger, you see the discharging current which is negative. If you connect a charger then the current what the charger gives will be used to supply your phone and the remaining power will be charged into the battery.