What is OA in OA79 Diode ?mohamed1234567892013-10-19T17:32:39+00:00 Home › Forums › General Electronics › What is OA in OA79 Diode ? This topic contains 2 replies, has 2 voices, and was last updated by Ligo George 2 years, 12 months ago. Viewing 3 posts - 1 through 3 (of 3 total) Author Posts April 24, 2013 at 10:43 pm #7374 mohamed123456789Participant What is OA in OA79 diode ? April 25, 2013 at 7:14 am #7392 Ligo GeorgeKeymaster The designation of OA is inherited from old European designation system for Vacuum Tubes. O – Cold Cathode A – Low Current Diode For More Details please visit this page .. http://en.wikipedia.org/wiki/Mullard%E2%80%93Philips_tube_designation June 25, 2014 at 3:37 pm #8900 Ligo GeorgeKeymaster 1NXXXX is an American Standard numbering system used for Semiconductor Devices which in now adopted globally. 1N means Single Junction semiconductor. 2N means Double Junction semiconductor. 4007 is the part number. Author Posts Viewing 3 posts - 1 through 3 (of 3 total) You must be logged in to reply to this topic.