One of the earliest schematics I crossed was the Howard W Sam's Photofact for a 1951 Westinghouse television.
It used the lower case letter 'u' for? mu, thus a 10 microfarad (microFarad) capacitor was marked? '10uf'? on the
schematic. Yes it was lower case? letter 'u' and lower case letter 'f'. Of course there were caps marked 'uuf'
for micromicrofarad, today referred to as picoFarad using the letter pair 'pF'.
It was not until encountering an IBM Selectric typewriter that the secretaries writing the typing the manuals
began using the actual ¦Ì symbol. Before that time, the used the lower lower case letter 'u' as that was the
closest thing on the manual Underwood manual typewriters of the period.
