HSD1型船用PH计样机于75年鉴定之后,我们与厦门第二分析仪器厂协作投入批量生产,提供有关单位使用。在生产和调试过程中,我们对该仪器的电路又作了一些改进。主要有三点:一、将由变容二极管作为调制元件的调制放大器改为由场效应管组成差动跟随器和运算放大器构成的直流放大器; HSD1 Marine PH meter prototype in 75 years after the appraisal, we and Xiamen Second Analytical Instrument Factory collaborated into mass production, providing the use of the relevant units. In the production and debugging process, we have made some improvements to the circuit of the instrument. There are three main points: First, the varactor diode as a modulation of the modulation amplifier replaced by the FET composed of a differential follower and operational amplifier DC amplifier;