There's an old symbol for a current source that's just two overlapping circles, reminiscent of a Venn diagram. There is more than one question on here with people asking what the symbol is, but I'm interested to know where it comes from; is it just an abstract symbol with no meaning behind it, or is it meant as a simplified drawing of something?
Symbol d in the above image (taken from wikimedia commons) is the one I'm asking about. Symbol a is the one that I am most familiar with, and I've never seen symbols b, c, or e before.
I'm aware that the precise reasoning behind any given symbol doesn't really matter, but I simply have an interest in... "etymology", I guess you could call it? ...now I've gotten to thinking about circuit diagrams as a language, and studying them from a linguist's point of view....
That's for another website, though.