A four-quadrant photocell is used in the system to replace photoelectric cell, and it acts both as centering detector and light intensity detector.是什么意思_A four-quadrant photocell is used in the system to replace photoelectric cell, and it acts both as centering detector and light intensity detector.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句