A.鐵制B.塑料制C.合金制D.銅制
A.增大動(dòng)接點(diǎn)片預(yù)壓力B.減小動(dòng)接點(diǎn)片預(yù)壓力C.增大前接點(diǎn)片壓力D.減小前接點(diǎn)片壓力