摘  要：通過直流電路驅動紅外二級管發出的紅外光恒功率發射，紅外光經過聚光透鏡，形成直徑為20 mm的光柱。帶材正常運動時處于光柱的中心位置，光電二極管接收到的光功率為一定值；當帶材偏移時，引起接收管的光功率變化，導致光生電流變化，從而確定偏移量與光生電流的關系。在信號的放大與處理環節采用兩級運算放大器相結合的電路，充分減少信號衰減與噪聲影響，并產生較大的電壓增益，試驗表明該電路設計可行并達到一定的精度。   關鍵詞：紅外二級管；恒功率；糾偏探頭；光生電流；運算放大器   中圖分類號：TP391.41；TN214        文獻標識碼：A          文章編號：1672-4984（2008）03-0127-04   Design and validate excursion sensor based on infrared diode   KANG Jing， ZHAO Qing-hai   （School of Printing and Packing Engineering，Xi’an University of Technology，Xi’an 710048，China）   Abstract： The infrared diode was droved by DC circuit to send light with constant power. The rays passed through a condensing lens and formed a light pole with the diameter of 20 mm. When the web worked normally, it passed through the central axle of the light pole so that the optical power received by photosensitive diode was normal constant. On the contrary, if the web went with excursion, different luminous flux would be gotten by the photosensitive diode. Furthermore, the photocurrent which had a direct proportion relationship with the luminous flux would be changed too. Based on the above, the relationship between the excursion and the photocurrent could be determined. Using two operational amplifiers to amplify and deal with the current signals, it could lessen the signal attenuation and yawp infections and produce biggish voltage plus. The experimental results shows that this designed circuit is available and with certain accuracy.   Key words： Infrared diode; Constant power; Excursion sensor; Photocurrent; Operational amplifier   Editor：liyan