Patent ID: 7170301

Claim:
A touch sensing apparatus comprising: a signal source for generating an alternating current signal; a conductor connected to the signal source; a sensor for receiving a noise generated by a contact of an object; wherein the sensor and the conductor form a simulated capacitor that results in alternating current signal flowing through the sensor when the sensor is contacted by the object; a detector having a first input end and a second input end, the detector upon receiving the alternating current signal output from the sensor resulting in voltage differences between the first and second input ends thereof, and outputting a signal; and a rectifying circuit for rectifying the alternating current signal generated by the signal source and simultaneously generating a noise; wherein one end of the rectifier circuit is connected to the signal source and the other end of the rectifier circuit is connected to the negative power input end of the detector; and a direct current power source, wherein the direct current power source is electrically connected to the second input end and a positive power input end of the detector, and provides a bias voltage for the detector.