In article ,
Telamon wrote:
In article ,
(Mark Zenier) wrote:
In article ,
Al Arduengo wrote:
If it says mfd it should mean mili-farads - not micro-farads.
Nobody uses millifarads, except maybe the boom car crowd. "mfd" or more
commonly "mf", prior to (the 1960's) metrification/SI rationalization
meant Microfarads. And picofarads were "mmf" micro micro farads.
Mark Zenier Washington State resident
That's not what I see in most articles or catalogs.
1 F is 1 farad
1 mF is .001 or 1x10^ -3 or 1 milli-farad
1 uF is .000,001 or 1 x 10^ -6 or 1 micro-farad
1 nF is .000,000,001 or 1 x 10^ -9 or 1 nano-farad
1 pF is .000,000,000,001 or 1 x 10^ -12 or 1 pico-farad
Many capacitors are in mF in industrial power supplies. Got to get the
current step response down to 20 Hz in some cases.
Man, I just dug out an older EEM (Electronics Engineers Master catalog)
and it's a MESS. Even in 1993, some outfits were still using MFD for
microfarads.
Millifarads are probably an artifact of Globalization (ie. of the outfits
that used MFD for uF in 1993 are probably now empty factories in the
US midwest after all their equipment got auctioned off to somebody
from Canton). Likewise nanofarads are pretty much of an indicator the
your capacitor was made by a European based manufacturer.
I'd only expect to see millifarads on big "Computer Electrolytics",
those beer can size (or bigger) with screw terminals.
The bottom line for project building hobbyists is that you need to take
into account when and where the magazine article or book was written.
There's a lot of stuff out there that's old enough to be really confusing.
(Several years back, I had an e-mail converstation with a guy who was
trying to find parts for a transistorized VLF reciever, and the writeup
included how to use it for detecting atmospheric atomic bomb tests,
which quit before 1963).
Mark Zenier
Washington State resident