in the parts list it says for example .047 mfd. i assume that this means microfarad and not millifarad
thanks
thanks
I would expect 0.047 mfd to mean microfarads = 47nF (nanofarads).
Millifarads is written mF.
Regards
Steve
Millifarads is written mF.
Regards
Steve
It probably means microfarad. Where it's used in the circuit will also give us a clue, looks like a size for a coupling capacitor.
Craig
Craig
As I recall the designation mfd was used to represent 'micro farad' because the printing devices used to apply the lettering could not duplicate the "micro" symbol (That fine lower case 'u' with the "tail"). This of course has led to some confusion........
I think the story is correct.......just a fragment of memory here.
Perhaps someone can confirm this.
________________________________________________________Rick....
I think the story is correct.......just a fragment of memory here.
Perhaps someone can confirm this.
________________________________________________________Rick....
what parts list?
The more information you give, the more accuracy of the responses you can get back.
FWIW milli is not used, or extremely rarely in the US! so if "the parts list" is from someplace other than?>
this parts list here
http://www.tubes4hifi.com/PAT-%204.pdf
for the dynaco pat4 preamp, it is halfway through the document on page 14
http://www.tubes4hifi.com/PAT-%204.pdf
for the dynaco pat4 preamp, it is halfway through the document on page 14
Long ago it would have been rare to have a millifarad, but today it's not uncommon. Old schematics would use mfd for microfarad. It's probably safe to say that if you see mfd, it's microfarad (uF), but if you see mF it's likely millifarad. It was also uncommon for anybody to use nanofarad (nF) in the old days, except maybe in Europe, but today it's common everywhere. IMO, anybody doing technical work of any type today should read the guide to SI units on the NIST site and try to use the preferred terms and abbreviations. OTOH, I've used microns for years and just can't get used to replacing it with micrometers, which to me are a machinists tool.
CH
CH
NO!
micro Farad is written shorthand as uF
milli Farad is writen shorthand as mF
mfd is shorthand for milli femto deci, i.e. gobbledegook.
youre not paying attention> please re-read the thread carefully! ie look at the US parts list that was referenced.
milliFarad is not used here in the USA.. probably to avoid confusion like here in this thread.
heck I remember when uuF or mmF was used instead of pF.
I have yet to see an actual part marked with mF instead of thousands of uF.
BTW SI and ENGINEERING units are different. at least my HP calculator knows the difference. LOL
" The millifarad is rarely used in practice, so that a capacitance of 4.7 × 10−3 F, for example, is usually written as 4,700 µF. North American usage also avoids nanofarads: a capacitance of 1 × 10−9 F will frequently be indicated as 1000 pF" from Wiki
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I have done and did.
You wrote a complete untruth and posted it here without explanatuion. Folk that read that could be mislead into believeing that what you posted is true.
It is not.
I posted my answer to your untruth.
It had nothing to do with the US mis-use of mfd.
I went on to show what the appropriate prefixes/multipliers should be in this case and showed why the mis-use of mfd is completely wrong.
Your posting and your reply does not help anyone.
yes, but many do not realise that the scientists have used the SI (system international) for a very long time.
Engineering, at least in Europe, uses the metric system. It is different, but similar enough to cause confusion. Here in the UK we changed to metric back in 1975 and yet our school teachers generally teach SI instead of metric out of ignorance that the two systems are different. So in that respect we are no better than many others for causing confusion.
When we know better we should (at least, I feel I must) correct the repeated errors seen on the Internet. If we don't, who will?
If all the errors, on the Internet, go unchallenged then eventually, maybe already, the errors will outnumber the correct.
No No NO!
Andrew you need to look at my answer in the context in which it was given. ( You need to look at the parts list in question!) Whether or not if YOU agree with the fact, that the US does not use milli is of no consequence and proves your limited exposure to industrial or commercial experience and practices. Your posting on this thread without due diligence just causes further confusion to this issue.
Andrew you need to look at my answer in the context in which it was given. ( You need to look at the parts list in question!) Whether or not if YOU agree with the fact, that the US does not use milli is of no consequence and proves your limited exposure to industrial or commercial experience and practices. Your posting on this thread without due diligence just causes further confusion to this issue.
FWIW, I've been in commercial instrumentation and electronics in the USA for quite a while and can confirm that nanofarad (nF) has become a commonly used term, seemingly in parallel with the adoption of SMT, and that millihenry (mH) has always been a commonly used term, as has milliohm. Millifarad (mF) only seemed to become more common when people started using huge reservoir/filter capacitors in their automotive sound systems, but it's still less common.
Conrad
Conrad
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