Original Text (This is the original text for your reference.)

A power supply protection device for an electric appliance includes a switching circuit for establishing an electrical connection to receive an external voltage from the external power supply and output the external voltage to the electric appliance, a detecting circuit for disabling the switch circuit to break the electrical connection when determining the external voltage is equal to or higher than a predetermined value, and an alert circuit for generating an alert signal when the electrical connection is broken and outputting the alert signal to a user.