光离子化检测器系统构成
Structure of photoionization detector system
光离子化检测器系统构成 检测器的系统构成，其主要部件包括敏感头单元（紫外灯，电离室，电极等），信号检测电路，微控制器，显示电路，人机接口电路和声光报警电路等。 被紫外灯电离的待测气体形成了离子，离子在极板电压的作用下，定向移动形成微弱电流。
The main components include sensitive head unit (UV lamp, ionization chamber, electrode, etc.), signal detection circuit, microcontroller, display circuit, man-machine interface circuit and acousto-optic alarm circuit. The gas to be measured ionized by UV lamp forms ions, which move in a directional direction and form a weak current under the action of plate voltage.
在外界条件（电离室结构，紫外灯强度）固定的条件下，电流的大小与气体的浓 度为线性关系。系统采用微弱信号检测电路，实现浓度→微弱电流→电压的线性转换，电压经过 差分放大后输入给单片机，由单片机控制信号的存储和显示，并将电压值转换为相应的浓度值输出。
When the external conditions (ionization chamber structure, UV lamp intensity) are fixed, the current has a linear relationship with the gas concentration. The system uses weak signal detection circuit to realize the linear conversion from concentration to weak current to voltage. The voltage is input to the single-chip microcomputer after differential amplification, and the signal storage and display are controlled by the single-chip microcomputer, and the voltage value is converted into the corresponding concentration value for output.