Re: Lesson R,L,C,T,V,D but Q and U ?
I reckon U for ICs is just a variation on μ (for μcircuit or microcircuit) corrupted further by being uppercase since uppercase μ is M which would really confuse things (megacircuit anyone?).
Perhaps LSI chips should be megacircuits?
VT I always thought was Valve Transistor, though TR could derive either from TRansistor or Transfer Resistor which was where transistor came from in the first place.
As long as the symbols are recognizable- not easy in some circuits either, the various prefixes used are at least cross referenced.
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