Re: good MMC? (different than first)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Mddeming-at-aol-dot-com>

In a message dated 3/15/01 10:20:30 AM Eastern Standard Time, 
tesla-at-pupman-dot-com writes: 


>
> > And an occasional source of confusion for me is that 1000 uF 
> > (microfarad) = 1 millifarad (mF), although "mF" is often seen being used 
> > to abbreviate microfarad. 
> > 
> >         -  Bill 
>
> The "mF" confusion is probably generated by formatting in 
> different font, relative to the original text: if the letter "m" 
> is formatted into the equivalent greek letter (i.e. in the 
> "symbol" font), it will show as the greek "mu", which would be 
> correct for "micro"(-farad, or anything else). - Me too have been 
> wondering many times about the millifarad confusion, before 
> noticing this. 
>
> Kurt Schraner 



Hi Kurt, All! 

The etymology of mfd predates, and therefore could not be a result of, font 
translation on computers. Back in the dim, dark days before multi-font 
computers/printers, most people who dabbled in electronics didn't use the 
Greek alphabet and neither did the printers of catalogues who sold stuff to 
them. Most electronics technicians, radio-TV repairmen, etc. were not college 
grads, so: 
1. It made no sense to use u instead of m as an abbreviation, unless one was 
familiar with Greek. 
2."m" existed on manual typewriters and linotype machines and "mu" didn't. 
The use of special characters increased typesetting costs. (a no-no for 
catalogues) 
3. Since a millifarad was far too large a unit to be of "practical" value, 
everyone would "know" the 'm' stood for micro when applied to caps, and milli 
when applied to coils. 
4. They also used mmfd to mean pfd (pico="micro-mirco"= 10^-6 x 
10^-6=10^-12). Most introductory books on electricity/electronics prior to 
~1970 also used these conventions. 
5. Most electrical equipment was built on a "human scale" by human beings. 
Prefixes like pico, nano, giga, and tera were meaningless to most people 
outside of research labs. Before the electronic chip, nothing useful to 
ordinary people had a surface measurable in nano-acres. 
6. Every industry started out with it's own conventions- standardization is a 
recent phenomenon. (The natural gas industry still uses Mcf for a thousand 
cubic feet and MMcf for a million.)