A membrane electrode assembly for a polymer electrolyte fuel cell having higher power-generating characteristics in a high-temperature, low-humidity environment, and a polymer electrolyte fuel cell using the same. A calibration circuit calibrates the phase-locked loop’s oscillator in the following manner. When \u201ckwy\u201d becomes more than or equal to \u201cb\u201d, \u201cb\u201d is subtracted from \u201ckwy\u201d, and a y-coordinate of a corresponding target pixel of an original image is changed by one pixel. The capacitance in the bushing between the main conductor and the stress shield conducts partial discharge current which is available for being sensed. In each embodiment, the beam combiners and the fold mirror are arranged along the same axis to further improve efficiency. The current measuring unit is connected to an output device in order to output the value of the measured current to an external test system via an external connection of the integrated circuit.