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pHS-3A型酸度计是四位数字显示的酸度计。本文以成都仪器厂的产品为例,对该仪器一些故障排除作一介绍,供使用和维修人员参考。一、电路概述整机中的直流稳压电源、放大器和A/D转换器各装在独立的印刷线路板上,分别称之为电源板、放大板和转换板,它们以插夹件形式相连接。电源部分由±12V两组电源组成。JC_(102)和JC_(104)(5G14B)是集成电源稳压器,三极管DD01起调整作用,输出电流为100mA。前置放大器线路示于图1。图中场效应管BG_201和BG_(202)(均为3D04E)组成单端输入、双端输出的对称差动放大级。BG_(203)和BG_(204)双三
The pHS-3A pH meter is a four-digit pH meter. In this paper, Chengdu Instrument Factory products, for example, some troubleshooting on the instrument to make an introduction for the use and maintenance personnel reference. First, the circuit overview The DC power supply in the machine, amplifiers and A / D converter installed in the independent printed circuit boards, respectively, called the power board, amplifier board and converter board, which in the form of plug-in phase connection. The power supply part is made up of ± 12V two groups of power sources. JC_ (102) and JC_ (104) (5G14B) are integrated power regulator, transistor DD01 play a regulatory role, the output current is 100mA. The preamplifier circuit is shown in Figure 1. Figure FET BG_201 and BG_ (202) (both for the 3D04E) form a single-ended input, double-ended output of the symmetrical differential amplifier stage. BG_ (203) and BG_ (204) double three