论文部分内容阅读
日立电镜真空系统中低真空检测元件多采用皮拉尼规(Pi)。其测量控制电路为一典型电路。仅以笔者见到的日立透射电镜H—300,H—500、H—600,扫描电镜S—450,S—520这部分电路形式完全相同。现以H—600电镜镜简低真空检测Pi_2为例分析其原理。皮拉尼规是一种电阻真空规,其构造为:金属外壳,壳内装有加热阻丝,阻丝由高温度系数金属制成。皮拉尼规作为惠氏电桥的一个臂构成控制电路。其检测方式叫恒温法,原理如下:开机时,真空度较低,气体分子多,热传导好,温度下降,电桥失去平衡。IC_24的1脚输出电压较高,因而增大了电桥供电电压
Hitachi electron microscope vacuum system low-vacuum detection components to use Pirani gauge (Pi). The measurement control circuit is a typical circuit. Only the author to see Hitachi transmission electron microscopy H-300, H-500, H-600, SEM S-450, S-520 this part of the circuit is exactly the same. H-600 electron microscopy is now a simple vacuum detection Pi_2 as an example to analyze the principle. Pirani gauge is a kind of resistance vacuum gauge, which is constructed as: a metal shell, the shell is equipped with heating resistance wire, the resistance wire is made of metal with high temperature coefficient. Pirany gauges as one arm of the Wyeth bridge form the control circuit. The detection method is called constant temperature method, the principle is as follows: boot, low vacuum, gas molecules, good heat conduction, the temperature dropped, the bridge out of balance. IC_24 1 foot higher output voltage, thereby increasing the bridge supply voltage