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.

--
Telamon
Ventura, California

Today mF most often means millifarad.
But in years past mF meant micro,
as in uF, farad.
Some diagrams as recent as the late 1990s
still used mF to equal uF.
Conversly, before the mid 1990s, no one but
the military EMP research labs had Farad or
milliFarad caps. I still remember when I saw
my first .47F capacitor. Kind of freaked me out.
I used a couple of 0.47 caps to replace the
lithium backup cells in my R2000 and my IC-28A.
If I had a few $100 to spare, I would be temtped to
buy one of the several Farad caps designed for the
automotive crowd. A cap that size would allow me
to coast through most power glitches.
Terry

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