"Charging for 5 minutes, talking for two hours" is known to almost everyone, but how does the voltage and current of the battery of the mobile phone change within five minutes of charging the mobile phone, and how much electricity is charged to the battery within five minutes? Smart home appliances such as washing machines and refrigerators, what is the current change and power consumption in different function modes and when they are in standby? These questions actually just use a power meter will allow us to see the process and results clearly!