Why do Americans not use nanofarads?

[AlfBaz]

Speaking of off-topic, what's the go with the pronunciation of Farad as Feh-raad by some Americans?

Interesting... It seems "Feh-raad" is the Pommy pronunciation
http://www.thefreedictionary.com/farad

[IanB]

Interesting... It seems "Feh-raad" is the Pommy pronunciation
http://www.thefreedictionary.com/farad

As a Pom I can say that both vowels in Farad are pronounced to rhyme with cat, with the stress firmly on the first syllable. (The second syllable may often be shortened to the unspecific "schwa" sound.)

[helloworld922]

To me 10000pF and 10nF are not the same:
10000pF means the precision of the capacitor is very high (<= 1%)
10nF = precision is 5-10% or less.

To me I read these as the same precision: accurate to 1 sig-fig.

I would read 1.0000e4pF, 10.000nF, 10000.pF, or 10001pF as being accurate to 5 sig-figs.

Speaking of off-topic, what's the go with the pronunciation of Farad as Feh-raad by some Americans?

I pronounce it fair-ad, or if I get lazy Fair-ed (mid-west).

[c4757p]

I read 10000pF and 10nF as having the same precision: "unspecified".

[amspire]

I read 10000pF and 10nF as having the same precision: "unspecified".

I agree. For a capacitor, I would never relate the number of digits to the accuracy. No-one would assume a 100,000uF electrolytic is a precision component.

[TerminalJack505]

What I think would be more interesting to know is how many people avoid the use of the term 'millifarad.' 

I don't remember where (probably a lecture) but I heard that it is bad form to use the term.  Supposedly due to the fact that MFD was used on capacitors at one time to specify microfarads.  Because of this, the use of mF is avoided so that there's no confusion with MFD.

[madires]

I read 10000pF and 10nF as having the same precision: "unspecified".

From a scientic or logical standpoint you're absolutely right!  (Un)fortunately humans got that weird feature called psychology :-) What would you think about a DMM displaying 1.1000V while having just 10% accuracy and a resolution of 0.1V? Most people would expect the DMM to display 1.1V.

[c4757p]

I use "millifarad". I think it is usually obvious - the same schematic also has proper microfarads, so you can see I'm not using "m" = micro, and it is usually pretty easy to tell what capacitor value is sensible to the neareast three orders of magnitude! I also use "milliohm" - no 0R33 for me, it's 330m. I often use the SPICEish Meg, since m and M look similar, though again, it should be obvious whether a certain resistor should be 0.33  ohms or 330,000,000.

[amyk]

What I think would be more interesting to know is how many people avoid the use of the term 'millifarad.' 

I don't remember where (probably a lecture) but I heard that it is bad form to use the term.  Supposedly due to the fact that MFD was used on capacitors at one time to specify microfarads.  Because of this, the use of mF is avoided so that there's no confusion with MFD.

Machines found it difficult to print the mu so they used MFD. This was many decades ago.

At the other end, we now have supercapacitors with several thousand Farads, but they don't seem to be using kF when referring to their value.s

[Sweeper]

As I mentioned previously in the tread I sent a question to Digikey regarding why they avoid nF. This is the reply I got:

"Thank you for your question.  Our decision to close our eyes to nanofarads was based on 2 factors that we were seeing in the industry.  Obviously ceramic capacitors and aluminum capacitors are where we see most product movement and therefore shaping the way we display capacitance.  Ceramic capacitor datasheets for the most part show their capacitance in picofarads, aluminum capacitors in microfarads.  With that parameter (Capacitance) being shared between the two families it was decided that 10000picofarads would be the breaking point to where we would switch to microfarads.  We are in midst of a project where if a user enters in "ceramic cap 1nf", it will return with the same results as a 1000pf ceramic capacitor."

I think the answer is a little convoluted and almost a non-answer. First they mention that data sheets for different kinds of capacitors (ceramic and electrolytic) tend to use pF and µF respectively and then they use this as the reason to avoid nF, but they make up another convention to change from pF to µF at 10 nF. So a 100 nF ceramic will be shown as 0.1 µF, despite it being a ceramic for which they claim the data sheet gives the value in pF. Not very logical in my opinion. But good that they will accommodate searches where the value is given in nF.

Per

[c4757p]

Seems like a pretty logical reason to me, actually. 100nF is an overlap point - there are 100nF electrolytics as well as ceramics. (Putting aside that I have yet to see a 100nF electrolytic in something less than a decade old...) So they're splitting the capacitors into "mostly ceramic" and "mostly electrolytic" and using the units that are most common in that group.

Personally I think that the storage system should be multiplier-agnostic - just store all values as floating-point farads. It would be extremely easy to write a program to convert all incoming databases from manufacturers into this format - interpreting prefixes like "p" and "u" is ridiculously straightforward, and for the manufacturers that store the values without a multiplier (e.g. "100" for "100 uF"), a quick glance at the database is enough to see that and make the appropriate change. Then lose the select box and have a text entry box, so that I can just type "100n", or "0.1u", or - what the hell - "0.0000000001 k". Even allow me to type in a tolerance in that box, so that if I type "100.01n 10%" it will give me 100nF capacitors.

[Sweeper]

So they're splitting the capacitors into "mostly ceramic" and "mostly electrolytic" and using the units that are most common in that group.

No, they split capacitors in 10 nF and less (and use pF for these) and above 10 nF (and use µF for these). 10 nF was never a dividing line between ceramics and electrolytics and today up 100 µF is quite common for ceramics. Maybe somewhere around 100 - 470 nF was a dividing line once upon a time.

I have a hard time seeing the logic behind this and if there ever was a rational reason for this convention I do not think that it still exists. Looks like an illogical legacy thing to me that is hard to justify today other than by referring to "legacy".

Per

[Sweeper]

I sent the same question to Mouser and this is the answer I got:

"Good afternoon my name is Brandon a technical support representative here at Mouser Electronics, Inc. There isn't really an answer to why not just us but the majority of the distributions only use PF and µF. It does cut of one option and makes our filter a lot easier without the NF in our parametric. Thank you for your inquiry and for choosing Mouser and have a great weekend."

Maybe he is right and that there is no fundamental reason why nF is avoided by some.

Per

[ampdoctor]

In my view the whole argument is ridiculous.  If the supplier database is using pF, and the mfg is using pF, why does the person drawing the schematic feel the need to us nF for any other reason than to be difficult and/or elitist.  It's just as easy to type a "p" or "u" as it is an "n", and only opens the door for the possibility of one more layer of mistakes in the design and mfg'g process.  Whereas the industry converting over to nF would be a project of herculean proportions.  Why somebody feels that a multi-billion dollar/year industry should allocate the time energy and capital to change a system that's functioning just fine to conform to the caprices of somebody who insists on using nano is beyond my comprehension.  Deal with it...jeeze!!!!

[Bored@Work]

In my view the whole argument is ridiculous. 

Well, how should I tell you this ...

THE industry is no longer what happens in the US.  The industry is what happens in the rest of the world. If the US wants to go on everyones tits, being it the aversion to nano or the ridiculios fascination with imperial units, they can certainly do that. But you are no longer in the position to tell the rest of the world to just deal with it.

Proper use of SI prefixes enables engineers around the world to quickly spot with which range of orders of magnitude they are dealing. The american spleen to avoid nano, or even to avoid any unit at all (fuck, do they mean micro, nano, pico?) just goes on everyones tits, and has probably created more misunderstandings than using the inocent nano where appropriate.

You know, since the beginning of this thread I have waited for one "argument": Because it is unamerican. Your answer came as close as it gets.

[ampdoctor]

From  my perspective at least being american or un-american doesn't really enter into it. I'm looking at it from a purely practical point of view. Whether you use Mouser, digikey, farnel element14 or whoever, they've got massive databases for not only online searches but inventory and purchasing that are all based in pF, and uF.  The mfg's have spec sheets, performance plots, etc all labeled in pF and uF. The silkscreens for labeling is all in pF and uF.  All of this would have to be changed, and it won't come cheap! The retooling and admin costs WILL be passed on to the consumer, who will immediately start complaining about how they're being fucked over by the big greedy manufacturers.  And God help them if somebody made a mistake somewhere. That opens up a whole 'nother can of worms!  I could care less what the unit is just that it's consistent across the supply and mfg chain. And while it may not be perfect there is a system in place already. And if there isn't a damn good reason to change it don't mess with it.

[Sweeper]

In my view the whole argument is ridiculous.  If the supplier database is using pF, and the mfg is using pF, why does the person drawing the schematic feel the need to us nF for any other reason than to be difficult and/or elitist.

Maybe because the idea of having prefixes in the first place is to make the numbers more readable to humans? Also, a few US people in this thread has already stated that they prefer to use nF rather than to skip it, so it is not just us strange Europeans (and maybe people from other parts of the world) doing it.

I personally have no trouble understanding and using nF and freely converting it to and from pF or µF when needed, but I am just curious as to what lead many Americans to avoid nF. There seems to be some sort of historical reason for it, but I do not think we have found the real answer in this thread yet.

  It's just as easy to type a "p" or "u" as it is an "n", and only opens the door for the possibility of one more layer of mistakes in the design and mfg'g process.  Whereas the industry converting over to nF would be a project of herculean proportions. 

Well, I think it is easier and less error prone to interpret e.g. 10 nF than 10000 pF. Heck, why not skip prefixes all together if they are error prone. How about 0.00000001 F and 0.000000001 F. Much easier than keeping track of what those pesky prefixes mean and how they relate to each other right? ;-)

No, I am not asking the US electronics industry to change its minds regarding this. I am just curious and trying to figure out whether the unreferenced Wikipedia statement is true (it seems to be to a large extent) and in if so, what the original reason for it is (so far I am almost as clueless about this as when I started this thread).

Per

[mzzj]

In my view the whole argument is ridiculous.  If the supplier database is using pF, and the mfg is using pF, why does the person drawing the schematic feel the need to us nF for any other reason than to be difficult and/or elitist.  It's just as easy to type a "p" or "u" as it is an "n", and only opens the door for the possibility of one more layer of mistakes in the design and mfg'g process.  Whereas the industry converting over to nF would be a project of herculean proportions.  Why somebody feels that a multi-billion dollar/year industry should allocate the time energy and capital to change a system that's functioning just fine to conform to the caprices of somebody who insists on using nano is beyond my comprehension.  Deal with it...jeeze!!!!

Picofarads or nanofarads, no biggie deal.

What I don't understand how the h*ll you still bother with imperial and US units. It's a total chaos. 

32 gauge copper wire(AWG) is different diameter than 32 gauge steel wire. Not to mention drill sizes, 32 gauge drill is yet different diameter and you have all the alphabet -sizes also 
1 Pint has different volume depending what you are measuring.
1 Inch varies depending if you happen to work for surveying or just measuring "other normal stuff"
1 Barrrel of oil, whiskey, petrol and beer are all different volume.  Standard barrel is yet different from any of  these.
1 ounce of gold is different from 1 ounce of steel.
I'd rather shoot myself on my leg than convert cubic inches to fl oz. 

[rea5245]

As an American, I'd just like to say that we don't use nanofarads because it's another stupid power-of-ten. We'd much prefer to use twelfths of a microfarad, or 1/5280th of a millifarad or something like that.

D*mn metric system.

[GK]

Dunno what the point of this thread should still be after 5 pages, but for some reason after skimming through all I'm thinking about right now are tits.



Hmmmm.........mesmerizing........... Those definitely aren't nano sized, kilo more like.

 

[AlfBaz]

...all I'm thinking about right now are tits.