一、引言在科研、文教、卫生和工农业生产中,人们常采用光电倍增管(其放大倍数一般达10°左右)作为光电转换元件以对微弱光信号进行检测;微弱光信号被光电倍增管转换成电信号后,因其过弱,还需要适当的放大,因此需要有一种高输入阻抗、低噪声、低漂移的直流放大器。当用光电倍增管来检测双光路的极微弱的萤光信 I. INTRODUCTION In scientific research, culture and education, public health and industrial and agricultural production, people often use photomultiplier tube (its magnification is generally about 10 °) as a photoelectric conversion element to detect weak optical signals; weak optical signals by photomultiplier tube Converted into electrical signals, because of its weak, but also need to enlarge, so there is a need for a high input impedance, low noise, low drift DC amplifier. When using a photomultiplier tube to detect the two-way very weak fluorescent signal