Patent search ap:("BELL TELEPHONE LABOR INC") AND inv:"ROMNES HAAKEN I" Page 1

1.

发明授权
Vacuum tube circuits 失效

公开(公告)号：US1917064A

公开(公告)日：1933-07-04

申请号：US52293231

申请日：1931-03-16

Applicant: BELL TELEPHONE LABOR INC

Inventor： ROMNES HAAKEN I

IPC: H01J1/13 , H03F1/54

CPC classification number: H03F1/542 , H01J1/135

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