chemelec Well-Known Member Oct 7, 2010 #21 Nigel Goodwin said: Presumably that was only in North America/Canada? - I've never seen it used in diagrams from anywhere else. Click to expand... Yes Nigel, In North America/Canada, back in the 50's and 60's.
Nigel Goodwin said: Presumably that was only in North America/Canada? - I've never seen it used in diagrams from anywhere else. Click to expand... Yes Nigel, In North America/Canada, back in the 50's and 60's.