I got this situation:
i got arduino connected with DFplayer “Mp3 player” which also connected to an amplifire "PAM8403 ".
attached is conenction diagram.
when the system is running using USB as power supply it works perfectly.
when using 9v battery, it runs for seconds then shuts down.
i think the mp3 module draws massive current that the arduino cant provide which leads to restarting of the arduino.
any ideas how to control this current spike or what to do ?!