美[θri pol swɪtʃ]英[θri: pəul switʃ]
[计] 三极开关
The three-pole switch was originally used to switch a voltmeter guard along with the signal lines .
三 刀 开关最早用于切换伏特计保护及信号线路。
Three-Pole Switch Test with Separating Single-Pole
独立单极的 三极 开关试验
美[θri pol swɪtʃ]英[θri: pəul switʃ]
[计] 三极开关