Why do Americans not use nanofarads? - Page 1
Forum section: electronics / general

author: Sweeper
author_rank: Contributor
timestamp: February 23, 2013, 10:49:53 am
content: It is my experience that Americans shun the prefix nano, at least before farads and I wonder why. If you search for capacitors on Digikey, smaller values up to 10 nF are shown in pF (10000 pF) and above that it is 0.011µF etc. The Farad article on Wikipedia says this."North American usage also avoids nanofarads: a capacitance of 1×10?9F will frequently be indicated as 1000 pF; and a capacitance of 1×10?7F as 0.1 ?F."The article on "nano" says something similar:"In the United States, the use of the nano prefix for the farad unit of electrical capacitance is uncommon; capacitors of that size are more often expressed in terms of a small fraction of a microfarad or a large number of picofarads."No reference or reason is however given in either of these articles. There are many other sites on the net that has the same or similar text (probably just copied from Wikipedia), but also without reference.One speculation that I have heard is that the letters n and u or µ in handwriting might be easy to mistake for each other, but I have not seen any sources for this.So, is there anyone here who knows why Americans avoid the nano prefix? I am mostly interested in references to trustworthy sources and not quite as interested in wild speculation.

author: EEVblog
author_rank: Unknown
timestamp: February 23, 2013, 11:12:24 am
content: IIRC this goes back a long way, like before the 1960's when I believe everyone in the world used either uF or pF, or sometimes mmf (mili-micro-farad!) was used to mean nFI'm not sure of the reasons behind the lack of nF in the early days though, but the US were not alone in doing this in the old days. They just haven't been dragged into the modern age like we haveDave.

author: Gall
author_rank: Frequent Contributor
timestamp: February 23, 2013, 11:15:33 am
content: I've seen really old USSR-made capacitors marked "100000mmf" or even "1000000mmf".

author: mark-r
author_rank: Contributor
timestamp: February 23, 2013, 11:27:07 am
content: One possibility is that I've noticed that in old publications (mainly British but some American) from before about the 1950s, prefixes smaller than micro weren't used at all. Very small capacitances were labelled as uuF (micro-micro-Farad, i.e. millionths of millionths of a Farad which is equivalent to a picofarad). For values around the nanofarad values, it seemed to be a matter of preference or house style whether to label a capacitor (or should I say condenser!) say 1000uuF or 0.001uF. (I'm using u for the greek mu because I'm not sure how to get a mu symbol here, texts of the day would universally use mu).Maybe when pF became more accepted, designers simply replaced uuF with pF, but were already used to there being no equivalent to nF so felt no compulsion to use it. In Europe where metrication and the SI units and prefixes were being adopted more rapidly than the US, perhaps we accepted nF more readily?All speculation, but plausible maybe? I don't buy the n being confused with mu explanation - surely in scribbled handwriting, p is more easily confused with mu?I expect the reason we associate this phenomenon with capacitors is that they are the only common component where pico- and nano- sized values are regularly used.

author: Sweeper
author_rank: Contributor
timestamp: February 23, 2013, 02:08:16 pm
content: According tohttp://physics.nist.gov/cuu/Units/history.html, the prefix micro existed in 1874 while Wikipediahttp://en.wikipedia.org/wiki/Metric_prefixclaims that micro, nano and pico were introduced in 1960 (I doubt Wikipedia is correct that it is meaningful to say that micro was not introduced until 1960).Clearly there was a period when micro existed, but not nano and pico, so I see the need for micromicrofarads etc (and I have seen that notation in old schematics as well). However, I doubt pico was introduced before nano and to me it seems more convenient to use both nano and pico and not just pico, so I am still confused why pico is so consistently preferred by US people.

author: w2aew
author_rank: Super Contributor
timestamp: February 23, 2013, 03:46:12 pm
content: As an analog design engineer in the US for 25 years, I guess I never really noticed any lack of use of nF for values between 1nF and 1uF. In my experience, nF was fairly popular. Specific example, I'd see 0.01uF about 60-70% of the time, 10nF used 30-40% of the time (and 10,000pF almost never).

author: casinada
author_rank: Frequent Contributor
timestamp: February 23, 2013, 03:50:16 pm
content: Probably if you use nano Apple will sue you

author: robrenz
author_rank: Super Contributor
timestamp: February 23, 2013, 03:55:36 pm
content: Quote from: mark-r on February 23, 2013, 11:27:07 amHold down the Alt key and type +0181

author: w2aew
author_rank: Super Contributor
timestamp: February 23, 2013, 03:59:04 pm
content: Quote from: robrenz on February 23, 2013, 03:55:36 pmDoesn't work for my iPad

author: robrenz
author_rank: Super Contributor
timestamp: February 23, 2013, 04:05:35 pm
content: Being an Apple product it should have some "obviously insanely intuitive no manual needed way" to insert the "µ"

author: jahonen
author_rank: Super Contributor
timestamp: February 23, 2013, 04:09:54 pm
content: Quote from: robrenz on February 23, 2013, 03:55:36 pmAt least on Windows, AltGr+m produces µ. I have finnish/swedish keyboard layout so YMMV.Regards,Janne

author: IanB
author_rank: Super Contributor
timestamp: February 23, 2013, 04:19:15 pm
content: Quote from: jahonen on February 23, 2013, 04:09:54 pmI was going to say it's hard to enter µ because the forum software eats it, but apparently you have succeeded.As a test, here is 10 microfarads written with the Greek letter mu and not the graphic character mu: 10 ?FAnd here is 1000 ohms: 1000 ?Let's see which of them survive.(Apparently neither of them.)

author: Sweeper
author_rank: Contributor
timestamp: February 23, 2013, 04:27:42 pm
content: Quote from: w2aew on February 23, 2013, 03:46:12 pmThat's positive. But there has got to be a reason that Digikey, Mouser, Arrow and Farnell consistently do not use nF, but only pF and µF despite the inconvenient numbers that result, whereas Swedish distributors like Elfa (http://elfa.se), RS Components (http://se.rs-online.com/) and Bejoken (http://www.bejoken.se/) also uses nF when appropriate.Per

author: jahonen
author_rank: Super Contributor
timestamp: February 23, 2013, 04:33:30 pm
content: Quote from: IanB on February 23, 2013, 04:19:15 pmI'm not sure if it is due to forum software but choice of character encoding in the database containing this forum. Perhaps it is set to some ISO-charset instead of UTF. Maybe Dave will tell us and could it be possibly changed?Regards,Janne

author: IanB
author_rank: Super Contributor
timestamp: February 23, 2013, 04:43:54 pm
content: Quote from: Sweeper on February 23, 2013, 04:27:42 pmI'd suggest it's due to a lack of customary use of SI measurements and prefixes in the US engineering community as a whole. Outside of electricity, SI prefixes like micro-, nano- and pico- are not in common usage (neither are milli-, kilo- or mega-). Something unfamiliar is less likely to be found in common usage.If we look back in British engineering practice before SI units became common, a 100 µF capacitor would have been marked 100 MFD.If we look today in US engineering we find things like "mil" for 1000th inch, MMSCFD for "million standard cubic feet per day" and Mlb for "thousand pounds".If the SI system of measurement is not common, then SI prefixes will feel somewhat foreign too.

author: mzzj
author_rank: Super Contributor
timestamp: February 23, 2013, 04:50:11 pm
content: testing: µF and microfarad.Not using nanofarads is not a big deal. Not using metric SI-system is a big deal.

author: DarkPrince
author_rank: Regular Contributor
timestamp: February 23, 2013, 04:58:08 pm
content: I can say tha at my university we use the term nano when necessary. So at least my university isnt pushing that crazy notion. Wouldn't accept it anyway.

author: Sweeper
author_rank: Contributor
timestamp: February 23, 2013, 05:06:47 pm
content: Quote from: IanB on February 23, 2013, 04:43:54 pmThat might be the most plausible suggestion so far I think. But it does not explain why the habit does not change. It is a global world in electronics nowadays and I am pretty sure American EEs have no trouble understanding nF in e.g. European circuit diagrams, so why not take advantage of this knowledge and simplify how they express a range of capacitance values? American electrical engineers are in my experience pretty well versed in the SI system, so just because most Americans do not have a clear sense of how heavy a kg is or how tall a person who is 1.80 m is does not really explain a consistent avoidance of nF by EEs. I find it really odd and I am still curious about this.Per

author: c4757p
author_rank: Super Contributor
timestamp: February 23, 2013, 06:21:13 pm
content: ThisAmerican uses "nano" all the time. 1000pF/10000pF/0.1uF is much clumsier than 1/10/100 nF![And Dave, I'm pretty sure MMF never meant "milli-microfarad"/nanofarad. I've done a lot of work with older (50s-60s) electronics from back when MMF was common, and it's always been "micro-microfarad"/picofarad.]

author: helloworld922
author_rank: Regular Contributor
timestamp: February 23, 2013, 06:26:22 pm
content: I've always written/used 100nF instead of 0.1uF (or 0u1F). I prefer 100nF or 0u1F because there's no decimal to lose, and 100nF doesn't have a "strange" notation where the metric scalar is used as a decimal holder. 100000pF is just too many digits to easily keep track of.That's just me, though, and I'm relatively new to electronics

author: c4757p
author_rank: Super Contributor
timestamp: February 23, 2013, 06:40:01 pm
content: I often switch multipliers to avoid writing a decimal point - 2200 pF instead of 2.2 nF, 4700 instead of 4.7 k, etc. I will also write "2n2", but not "2n2F" - that looks weird.Quote from: helloworld922 on February 23, 2013, 06:26:22 pmAnyone who writes "100000pF" should never be allowed to write a zero ever again. Is "hanged, drawn and quartered" too much?

author: Sweeper
author_rank: Contributor
timestamp: February 23, 2013, 07:06:17 pm
content: Quote from: c4757p on February 23, 2013, 06:21:13 pmThat's good. I totally agree with you regarding the clumsiness.I just sent a question to Digikey to see if they can come up with a reason for avoiding nF. This seems to be harder to figure out than I expected.Per

author: c4757p
author_rank: Super Contributor
timestamp: February 23, 2013, 07:17:16 pm
content: While you're at it, write Mouser and ask them why they can't be bothered to normalize values at all. Why I have to select "1 watt", "1 Watt" and "1000 mW" to see 1W resistors is beyond me.

author: SeanB
author_rank: Super Contributor
timestamp: February 23, 2013, 07:25:31 pm
content: That is because of mixing systems over the years...............You will have had various entry operators who each used a different system.

author: JoeyP
author_rank: Frequent Contributor
timestamp: February 23, 2013, 08:09:24 pm
content: This American routinely uses nanofarads, and has been doing so for decades. I find it odd every time I have to specify 10000pF to order 10nF caps from Digikey. I'd have no issue with 0.01uF but there seems no justification for 10000pF.

author: Martin.M
author_rank: Frequent Contributor
timestamp: February 23, 2013, 09:00:24 pm
content: I have found the following hier in germany:1000pF1nF1020,001/voltagebrown-black-red- following colors for tolerance and voltage (compare to american Micas and bumble bees)and vintage: 1000cmgreetingsMartin

author: Pentium100
author_rank: Frequent Contributor
timestamp: February 24, 2013, 05:03:01 am
content: In a lot of USSR circuit diagrams the units "pF" or "uF" are not specified as such, if the value is without a decimal point (200) then it is picofarads (or ohms), if it is specified with a decimal point (1,0) then it is microfarads (or megaohms). Kiloohms are marked with a letter "k" though.

author: c4757p
author_rank: Super Contributor
timestamp: February 24, 2013, 05:14:24 am
content: That's common in older American schematics too.

author: jh15
author_rank: Frequent Contributor
timestamp: February 24, 2013, 05:41:17 am
content: At least on Windows, AltGr+m produces µ. I have finnish/swedish keyboard layout so YMMV.Regards,JanneShouldn't it be YKMV in Finland?

author: IanB
author_rank: Super Contributor
timestamp: February 24, 2013, 05:45:52 am
content: Quote from: jh15 on February 24, 2013, 05:41:17 amAh, but in metric countries fuel consumption is measured in litres per km. So it would be "literage"

author: amspire
author_rank: Super Contributor
timestamp: February 24, 2013, 06:34:02 am
content: I know back in the 70's and 80's, some of the companies I had contact with had a strict policy to avoid nanoFarads and milliFarads to avoid confusion, particularly at a time when there was far more manual assembly. Even though parts often came on reels, the leads would be cut and formed in stores ready for hand placement, and the assemblers would pick parts out of bins.A 100nF polyester cap could be the same size as a silver-mica 100pF cap. Since caps rarely used colour-code to represent values and some caps had no "p", "n" or "u", it was really easy to make mistakes. Is a ceramic cap with just "33" on it 33pF or 33nF? If you only buy capacitors that use 33 or 33p for 33pF and 0.033 or 0.033u for 33nF, it was hard to make a mistake.In the surface mount era, it is not as big an issue. If you are dependent upon someones eyesight to check the correct valued resistors and capacitors are in place, you are in big trouble.I have no idea if any companies still avoid nF as a strict policy. I think today, if you can get a part labelled 10nF cheaper then an equivalent part labelled 0.01uF, it is a no-brainer - you get the cheaper part.

author: Sweeper
author_rank: Contributor
timestamp: February 24, 2013, 08:01:08 am
content: Quote from: amspire on February 24, 2013, 06:34:02 amIt sounds reasonable that it was in order to avoid some kind of confusion that companies banned the use of nF. Still, the "solution" requires more characters (0.033 as opposed to 33n or 10000 as opposed to 10n e.g.) than the alternative to use the prefix nano, so if the problem was the limited space to print characters on components, the solution seems somewhat backwards. Maybe I am expecting too much rationality here...I wonder if IEEE had some policy or recommendation regarding the (non-) use of nF.Per

author: thmjpr
author_rank: Regular Contributor
timestamp: February 24, 2013, 08:14:58 am
content: Quote from: SeanB on February 23, 2013, 07:25:31 pmSure this explains the initial variations, but does not explain why they would not fix them. Updating a database where value = 1w, 1 watt, 1000mw and renaming to 1 Watt should be trivial.Reminds me of a checkout bug on Newark. If I didn't fill out the billing address correctly (some unimportant line needed to be filled) it would display a generic message "system error has occurred". Leaving the buyer clueless, possibly in search of another distributor.

author: jahonen
author_rank: Super Contributor
timestamp: February 24, 2013, 08:17:19 am
content: Quote from: IanB on February 24, 2013, 05:45:52 amActually, litres per 100 km is much more commonly used "unit" here to get numeric values usually between 1 and 10.Regards,Janne

author: PA4TIM
author_rank: Super Contributor
timestamp: February 24, 2013, 05:44:43 pm
content: One of the leading companys in the USA in the field of measuring capacitance was General Radio. On my GR-1608 the range switch gives pF, nF, uF and mF ( desingned in 1962 and I have a very early version according to Henry Hall who designed them because my oscillator/detector was all germanium) I do not think they would use nF if it was allmost never used.So nF was known in the USA, at least the last 50 years ;-)

author: Martin.M
author_rank: Frequent Contributor
timestamp: February 24, 2013, 06:11:15 pm
content: the friends in the states use all,on our scopes you see graticules of a cm, not half inchesgreetingsMartin

author: beaker353
author_rank: Unknown
timestamp: February 24, 2013, 09:19:08 pm
content: I use nF all the time. In my EE classes the instructors are very strict about staying in standard SI units/prefixes/suffixes. The numeric part of an answer must be less than 1,000 and equal to/more than 1. Outside that range your answer in considered wrong, period.-EM

author: rsjsouza
author_rank: Super Contributor
timestamp: February 24, 2013, 10:05:57 pm
content: Quote from: thmjpr on February 24, 2013, 08:14:58 amConceptually and practically it seems a trivial task, but you would be surprised to see how difficult it is to merge such databases in a foolproof manner and to cover all occurrences in all the relevant data fields, especially when they come from different manufacturers with different file formats. Imagine every manufacturer specifying their 10000pF/10nF/10kpF and so on?In my experience the distributors do not manually input that data, as it is expensive, error prone and unreliable. They have to trust the suppliers to provide this database, and not many may be as cooperative to change their own internal standards to ease the distributor's life.

author: c4757p
author_rank: Super Contributor
timestamp: February 24, 2013, 10:11:44 pm
content: It really should not be hard to write a script that understands engineering units and prefixes. Even the horrid bastardization "10kpF" should be an easy one. Actually, I regularly use a calculator I wrote myself that would understand all of these just fine. I get the idea that DigiKey does this, actually - their component values seem to be relatively normalized.

author: FenderBender
author_rank: Super Contributor
timestamp: February 25, 2013, 01:20:07 am
content: Quote from: Sweeper on February 23, 2013, 10:49:53 amBecause we want everyone in the world to hate us... even more.In all seriousness, I really haven't ever been under the impression that American engineers are against nF in any way. Some of the older naming conventions might still be in place, but I don't think too many people are going to say "I need a 0.001uF capacitor"..I don't think.

author: BravoV
author_rank: Super Contributor
timestamp: February 25, 2013, 03:41:17 am
content: Quote from: Martin.M on February 24, 2013, 06:11:15 pmReally, is there such scope with imperial graticule ?

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 25, 2013, 05:46:38 am
content: I use millifarads and nanofarads as I need to. Since I do a lot of work on power electronics, it turns out I end up using them a lot. I have also been using the unit as a decimal for a few years now, the reasoning is that if the text gets smudged (easy to do on a rough draft), the decimal point is very easy to miss and the error might not be obvious on some designs.

author: Sweeper
author_rank: Contributor
timestamp: February 25, 2013, 06:19:50 am
content: Based on the comments here from Americans it seems like the "situation" is better than I expected in that lots of Americans apparently use nF happily.Still, the big distributors avoid it and Wikipedia says "North American usage also avoids nanofarads [...]", so I still believe there is something to it, although the nF-phobia (if it ever existed) might hopefully be going away.Per

author: helloworld922
author_rank: Regular Contributor
timestamp: February 25, 2013, 07:08:09 am
content: Must be related to the huge push for "nano-technology"My local uni's clean room was renamed from the microfab to the nanofab because of this.

author: eliocor
author_rank: Unknown
timestamp: February 25, 2013, 11:43:12 am
content: 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.

author: Tepe
author_rank: Frequent Contributor
timestamp: February 25, 2013, 11:48:15 am
content: Quote from: jahonen on February 24, 2013, 08:17:19 amAround here we use km/l so I guess it must be "kilometerage"

author: madires
author_rank: Super Contributor
timestamp: February 25, 2013, 11:58:45 am
content: Quote from: eliocor on February 25, 2013, 11:43:12 amVery true! I also would expect a high accuracy for a 10000pF cap. It's amazing how the different systems are impacting the view.PS: I happily admit that I'm using m, µ, n, p and f since I learned about them in school :-)

author: Zeta
author_rank: Contributor
timestamp: February 25, 2013, 02:39:40 pm
content: Quote from: Sweeper on February 23, 2013, 10:49:53 amMost EE use nF nowadays but distributors might be using pF out of conveniencesince because most Ceramic disk capacitor markings have been in pF.for example, a capacitor marked 101 means 100pF while a capacitor marked 104 means 100nF (100000pF). I actually find it more convenient to have a part marked as 222 rather than 2n2.

author: _Sin
author_rank: Regular Contributor
timestamp: February 25, 2013, 02:50:20 pm
content: Quote from: robrenz on February 23, 2013, 04:05:35 pm(off topic, but if you want to type greek letters on an i-device, you turn on the greek keyboard...)

author: AlfBaz
author_rank: Super Contributor
timestamp: February 25, 2013, 03:03:36 pm
content: Speaking of off-topic, what's the go with the pronunciation of Farad as Feh-raad by some Americans?

author: AlfBaz
author_rank: Super Contributor
timestamp: February 25, 2013, 03:11:34 pm
content: Quote from: AlfBaz on February 25, 2013, 03:03:36 pmInteresting... It seems "Feh-raad" is the Pommy pronunciationhttp://www.thefreedictionary.com/farad

author: IanB
author_rank: Super Contributor
timestamp: February 25, 2013, 03:41:19 pm
content: Quote from: AlfBaz on February 25, 2013, 03:11:34 pmAs 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.)

author: helloworld922
author_rank: Regular Contributor
timestamp: February 25, 2013, 08:04:53 pm
content: QuoteTo 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.QuoteI pronounce it fair-ad, or if I get lazy Fair-ed (mid-west).

author: c4757p
author_rank: Super Contributor
timestamp: February 25, 2013, 08:19:36 pm
content: I read 10000pF and 10nF as having the same precision: "unspecified".

author: amspire
author_rank: Super Contributor
timestamp: February 25, 2013, 11:25:58 pm
content: Quote from: c4757p on February 25, 2013, 08:19:36 pmI 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.

author: TerminalJack505
author_rank: Super Contributor
timestamp: February 26, 2013, 05:42:38 am
content: 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.

author: madires
author_rank: Super Contributor
timestamp: February 26, 2013, 03:25:55 pm
content: Quote from: c4757p on February 25, 2013, 08:19:36 pmFrom 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.

author: c4757p
author_rank: Super Contributor
timestamp: February 26, 2013, 03:41:35 pm
content: 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.

author: amyk
author_rank: Super Contributor
timestamp: February 26, 2013, 06:48:30 pm
content: Quote from: TerminalJack505 on February 26, 2013, 05:42:38 amMachines found it difficult to print the mu so they used MFD. This was many decades ago.At the other end, we now havesupercapacitorswith severalthousandFarads, but they don't seem to be using kF when referring to their value.s

author: Sweeper
author_rank: Contributor
timestamp: February 27, 2013, 05:23:30 pm
content: 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

author: c4757p
author_rank: Super Contributor
timestamp: February 27, 2013, 05:35:35 pm
content: 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.

author: Sweeper
author_rank: Contributor
timestamp: February 27, 2013, 05:52:02 pm
content: Quote from: c4757p on February 27, 2013, 05:35:35 pmNo, 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

author: Sweeper
author_rank: Contributor
timestamp: March 02, 2013, 10:53:43 am
content: 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

author: ampdoctor
author_rank: Frequent Contributor
timestamp: March 02, 2013, 07:02:52 pm
content: 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!!!!

author: Bored@Work
author_rank: Super Contributor
timestamp: March 02, 2013, 07:22:52 pm
content: Quote from: ampdoctor on March 02, 2013, 07:02:52 pmWell, 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.

author: ampdoctor
author_rank: Frequent Contributor
timestamp: March 02, 2013, 08:04:30 pm
content: 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.

author: Sweeper
author_rank: Contributor
timestamp: March 02, 2013, 09:07:16 pm
content: Quote from: ampdoctor on March 02, 2013, 07:02:52 pmMaybe 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.Quote from: ampdoctor on March 02, 2013, 07:02:52 pmWell, 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

author: mzzj
author_rank: Super Contributor
timestamp: March 02, 2013, 09:16:02 pm
content: Quote from: ampdoctor on March 02, 2013, 07:02:52 pmPicofarads 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 also1 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.

author: rea5245
author_rank: Frequent Contributor
timestamp: March 03, 2013, 03:05:47 am
content: 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.

author: GK
author_rank: Super Contributor
timestamp: March 03, 2013, 03:18:20 am
content: 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.

author: AlfBaz
author_rank: Super Contributor
timestamp: March 03, 2013, 06:37:08 am
content: Quote from: GK on March 03, 2013, 03:18:20 am