张丝 meaning in English

tensile spring
tensioned wire

Elements for electrical instrumentation . tautband and suspension
电工仪表用零部件.张丝和吊丝
General model c38 dc meters are portable taut - band suspended moving coil instruments with light - spot indication . the meters have the feature of extremely high in sensitity and small in consumpition being particularly suitable to be used for measuring weak electric quantity on dc circututs , also for testing the static paramenters of transistors as well for measuring the output of millivolt values of zhermocouple in the vacuun furnaces ( or hydrogen furnaces )
C38型直流电表是磁电系张丝支承光点指示可携式电表仪表具有极高的灵敏度，功耗小，特别适合弱电量直流电路测量及晶体管静态参数测试用以及用做真空炉(或氧气炉)中测量热电偶的输出毫伏值