英语语法分析

The varistor and the resistor are mounted externally.

变阻器和电阻器安装在外面。

But now, there is not a standard method to estimate the aging degree of ZnO varistor.

目前在判断氧化锌压敏电阻的老化程度方面还没有标准的方法可循。

Product quality is stable, reliable performance, is the domestic first-class ring varistor manufacturers.

产品质量稳定，性能可靠，是国内一流的环形压敏电阻器生产企业。