A present invention provides a PDA with built-in voltage protection,
comprising a main device, a socket, and a voltage protection module. The
main device performs necessary data processing. The socket connects to an
adapter. The voltage protection module is coupled between the main device
and the socket, wherein the voltage protection module receives an input
voltage from the adapter and allowing the input voltage to be applied to
the main device when the input voltage is between a preset maximum
voltage and a preset minimum voltage.