Patent ID: 8885303

Claim:
An electronic device comprising: a main body comprising a circuit board; an outer covering having a metal surface; a central processing unit disposed in the main body; and a protective device disposed in the main body, the protective device coupled to the central processing unit and configured to send at least one warning signal to the central processing unit so that the central processing unit stops operating when the outer covering and the main body are not closed tightly, wherein the protective device comprises: a first contact disposed on the circuit board; a second contact disposed on the circuit board; and a first logic circuit coupled to the first contact and the second contact, wherein the first logic circuit is directly connected to the central processing unit, wherein the first contact and the second contact touch the metal surface when the outer covering and the main body are closed tightly so that the first logic circuit outputs one first logic signal to the central processing unit, and the first logic circuit outputs an other first logic signal as the at least one warning signal to the central processing unit when at least one of the first contact and the second contact fails to touch the metal surface, wherein a level of said one first logic signal is different from a level of said other first logic signal, wherein the central processing unit continues to operate according to said one first logic signal or stops operating according to said other first logic signal.