Patent ID: 8243945

Claim:
An earphone jack for connecting an earphone plug, comprising: a jack module, the jack module including a connecting hole for receiving the earphone plug, a contacting member, and a grounded movable member; and a detecting module connected to the contacting member; wherein when the earphone plug is not received in the connecting hole, the contacting member is connected to the movable member to be grounded, and the detecting module correspondingly outputs a first electric potential for indicating that the earphone plug is not connected to the earphone jack; and when the earphone plug is received in the connecting hole, the movable member is resisted by the earphone plug and separated from the contacting member, and the detecting module correspondingly outputs a second electric potential for indicating that the earphone plug is connected to the earphone jack; wherein the detecting module includes a transistor and a detecting connector, the transistor including a base, an emitter, and a collector, the base connected to the contacting member, the emitter grounded, and the collector connected to the detecting connector; the first and second electric potentials output from the detecting connector; wherein the earphone jack further comprises a power supply connector for connecting a power supply; the power supply connector connected to the base, the collector, and the contacting member; wherein when the contacting member is connected to the movable member to be grounded, the power supply is grounded through the power supply connector, the movable member and the contacting member, such that the transistor is turned off and the first electric potential is correspondingly generated and output from the detecting connector; and when the contacting member is separated from the movable member, the power supply provides an electric potential to the base to turn on the transistor, such that the second electric potential is correspondingly generated and output from the detecting connector; and wherein the detecting module further includes two resistors, one of the two resistors is connected between the power supply connector and the collector, and the other of the two resistors has one end connected to the power supply connector and another end connected to the base and the contacting member.