matt weber wrote:

On 28 Jan 2005 16:37:51 -0800, wrote:

snip


Thanks in advance.
mfd=Microfarads or uF. In other words buy yourself a nice big
electrolytic cap (about 30wvdc for make sure it surives) and put it
across the leads. Get it at Ratshack, or any electronic parts
supplier.

If it says mfd it should mean mili-farads - not micro-farads.

-A
--
~/.signature

Al Arduengo wrote:

mfd=Microfarads or uF. In other words buy yourself a nice big
electrolytic cap (about 30wvdc for make sure it surives) and put it
across the leads. Get it at Ratshack, or any electronic parts
supplier.


If it says mfd it should mean mili-farads - not micro-farads.


Not in the USA.


================================================
Only metric prefixes for 10+6 or more have an upper-case abbreviation (e.g.,
M = 10+6, G = 10+9, etc.). In particular, note that the prefix m indicates
10-3 and M indicates 10+6. The difference between an upper-case M and a
lower-case m is nine orders of magnitude! One should be warned that American
manufacturers of capacitors often use "mF" or "MF" to indicate microfarads,
a practice that is both incorrect and misleading.

The proper abbreviation for "kilohertz" is "kHz": only the "H" is upper case.

Note that the proper abbreviation for "second" is "s", not "sec".

The same abbreviation is used for the singular and plural form of a unit.

A period is not placed after an abbreviated unit, unless it is at the end of
the sentence.

http://www.rbs0.com/tw.htm

==================================================


==================================================
* mF: Milli-Farad, 1x10-3 Farad (1,000th of a Farad) - uncommon
* uF: Micro-Farad, 1x10-6 Farad (1,000,000th of a Farad)
* mF: Micro-Farad, a very, very old term, still sometimes used in the
US (True!) - Causes much confusion.
* ufd: Micro-Farad, another very old term, still used in the US
* mfd (or MFD): Yet another antiquated term - US again!
* nF: Nano-Farad, 1x10-9 Farad (1,000,000,000th of a Farad) - Common
everywhere except the US
* pF: Pico-Farad, 1x10-12 Farad (1,000,000,000,000th of a Farad)
* mmF: Micro-Micro-Farad, another extremely old term, also still used
sometimes in the US

http://sound.westhost.com/beginners.htm

================================================== =





mike

m II wrote:

Al Arduengo wrote:

mfd=Microfarads or uF. In other words buy yourself a nice big
electrolytic cap (about 30wvdc for make sure it surives) and put it
across the leads. Get it at Ratshack, or any electronic parts
supplier.


If it says mfd it should mean mili-farads - not micro-farads.

Not in the USA.

It seems the times are changing. 'Mfd' has always meant micro-farads in
the US but with the large capacitors being made now, 'uf' is becoming a
better notation so it's not confused with 'milli-farads' for the big
caps'.

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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

Thanks for the replies... So what does 50,000 mfd translate to in uF?
..5? .05?


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

maybe this will help

base unit one farad
millifarad = 1/1000 farad or a thousands of a farad (seldom used for
capacitors)
microfarad = 1/1,000,000 farad or a millionth of a farad

unfortunate the mixup of the prefixs "m"

In some measurements such as current
..001 amp is expressed as one mA m meaning milli
..000001 amp is expressed as one uA u meaning micro

So back to your original question - you need to ascertain the use of m
A 50,000 millifarad is a whopping capacitor and not likely
So it was probably 50,000 microfarads

Hope that helps

--
Caveat Lector



wrote in message
oups.com...
Thanks for the replies... So what does 50,000 mfd translate to in uF?
.5? .05?


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

In article .com,
wrote:
Thanks for the replies... So what does 50,000 mfd translate to in uF?
..5? .05?

50,000 uF. Probably about the size of small can of V8 juice, given the
voltage rating you'd use in a car (16 or 25 volts?). The newer they are,
the smaller they get, so I might be showing my age.

Mark Zenier Washington State resident

Mark Zenier ) writes:
In article .com,
wrote:
Thanks for the replies... So what does 50,000 mfd translate to in uF?
..5? .05?

50,000 uF. Probably about the size of small can of V8 juice, given the
voltage rating you'd use in a car (16 or 25 volts?). The newer they are,
the smaller they get, so I might be showing my age.

The first power supply I built, in the early seventies, I bought at
a hamfest a 10,000uF capacitor with about a 16v rating. Big stuff at
the time. It's the size of a Coke can, and has those screw terminals.
"Computer grade" was what similar capacitors in the surplus store
ads were called.

Pretty useless these days, given that you can get bigger capacitance
and a higher voltage rating in a much smaller package.

Micahel

Thanks Mark! I got my noise filter today and will get it hooked up
this weekend. I'm hopeful that it resolves the alternator whine by
iteself, but I expect it will take a cap to totally fix it.

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