According to China's standard regulations, the USB power socket usually outputs a voltage of 5 volts (5V). This is because the USB (Universal Serial Bus) standard specifies that its voltage is 5V, which is more suitable for charging and data transmission of electronic devices.
Through this 5V voltage, we can connect various devices such as mobile phones, tablets, cameras, and can charge or transmit data via USB cable. So, when we plug in a USB power socket at a 220-volt power outlet, we can get a stable 5-volt voltage output to meet our needs for the device.
The standard USB socket is 5V, so no matter how many volts of the power socket, the USB output is 5V.