单项选择题
A.静铁心B.衔铁C.接线柱D.触头压力弹簧
A.85%~105%B.65%~95%C.70%~100%D.50%~70%
A.电源接上接线座,负载接上接线座B.电源接下接线座,负载接下接线座C.电源接上接线座,负载接下接线座D.电源接下接线座,负载接上接线座