Improved method of and apparatus for opening or closing an electrical circuit at anypredetermined point in the cycle of an alternating current or potential therein
摘要
申请公布号
GB527703(A)
申请公布日期
1940.10.15
申请号
GB19390004724
申请日期
1939.02.13
申请人
ROBERT SIMPSON SILVER;IMPERIAL CHEMICAL INDUSTRIES LIMITED
