Abstract
A sensor capable of preventing a non-symmetrical coupling effect caused by an excessive exposure intensity comprises: a sensor cell, a buffer, and a clamping circuit connected with the buffer. The clamping circuit outputs a clamping voltage larger than twice of the start voltage so that the sensor cell can receive a high intensity photo signal from the outside so that the sensor cell operates in a linear region in order to avoid the sensor cell from entering a non-linear region or even turned off and generating a non-symmetrical coupling effect, thereby ensuring the quality of the image.