Capacitors: UF = MFD but what the heck is NF?

[olds...@tubes.com]

40 years ago, back when I did a lot with electronics, capacitors were
either F (farads), UF or MFD microfarads, (UF and MFD were the same
thing), or PF (Picofarad). Now they are using NF. What the heck is that?

I just bought one of these digital meters that not only measure voltage,
current and ohms, but also measures caps. I just grabbed some old
paper/wax caps (because they were handy).

A .5 cap is reading .455 UF

but a
.1 UF cap is reading 106.3 NF
(why the heck does it not read in terms of UF?)

.01 cap is showing

.05 cap is showing 52.6 NF

.02 (ceramic cap) is reading 15.86 NF

40 UF electrolytic is reading 48.1 UF

I could go on, but the ones that are reading in terms of UF are close to
right. (old caps so they are not real precise).

But those reading NF have my head spinning.....
There is no means to change the settings to read UF instead of NF. I am
completely lost and confused!!!

Unfortunately I do not have any PF caps that are not connected to a
circuit, so I dont know if that would read PF or NF or UF.....

Seems we live in a time when everything that was once simple has become
complicated and for no advantage. Kind of reminds me of trying to
determine if I need a 1/2" or a 12 mm socket, when both look to be the
same size.... More senseless complication....

[MJC]

In article <mvv1cct7jqnr4kpf4...@4ax.com>,
olds...@tubes.com says...

Doesn't your head spin with feet, inches, furlongs, bushels, and so
forth? To the extent that a probe can crash into Mars?

(I'm waiting to see whether the UK, where I live, starts to reverse its
slow reluctant switch to metric measurements when it leaves the EU!)

Mike.

[dansabr...@yahoo.com]

1 mF (millifarad, one thousandth (10−3) of a farad) = 1000 μF = 1000000 nF
1 μF (microfarad, one millionth (10−6) of a farad) = 0.000 001 F = 1000 nF = 1000000 pF
1 nF (nanofarad, one billionth (10−9) of a farad) = 0.001 μF = 1000 pF
1 pF (picofarad, one trillionth (10−12) of a farad)

Dan

[whit3rd]

On Wednesday, March 8, 2017 at 11:40:31 PM UTC-8, olds...@tubes.com wrote:
> 40 years ago, back when I did a lot with electronics, capacitors were
> either F (farads), UF or MFD microfarads, (UF and MFD were the same
> thing), or PF (Picofarad). Now they are using NF. What the heck is that?
>

It's Systeme Internationale (so, blame the French).

Standard metric prefixes for SI units include Greek letter mu (µ) often rendered with
lowercase 'u', meaning micro, 10^-6. 'n' (has to be lowercase!) for 'nano', 10^-9.
Cannot use the capital M like lowercase, 'MF' would mean mega-farads, and the 'MFD' would
not look like ANY real unit of measurement.

[Ralph Mowery]

In article <mvv1cct7jqnr4kpf4...@4ax.com>,
olds...@tubes.com says...
>

> 40 years ago, back when I did a lot with electronics, capacitors were
> either F (farads), UF or MFD microfarads, (UF and MFD were the same
> thing), or PF (Picofarad). Now they are using NF. What the heck is that?
>
>

Thought you were old school.

What is the PF stuff ??? For me it was usually uF and uuF for the small
stuff and the MFD was for the larger capacitors.

I am not old enough to remember when most all capacitors were called
condensers all the time. For me most electronics was capacitors and the
condensers were used across the points of gas engines.

I think that NF stuff was (is) an attempt to get numbers to the left of
the decimal point. While not exectally,but similar to the scientific
notation where you have one number to the left of the decimal point and
all the others to the right raised to a power of ten.

[MJC]

In article <MPG.332b394e4...@news.east.earthlink.net>,
rmower...@earthlink.net says...

were used across the points of gas engines.
>
> I think that NF stuff was (is) an attempt to get numbers to the left of
> the decimal point. While not exectally,but similar to the scientific
> notation where you have one number to the left of the decimal point and
> all the others to the right raised to a power of ten.

Yes, and definitely not rendered with no digit (not even a zero!) before
the dot, as in OP's posting. It would be too easy to fail to notice the
dot and get the measure very inaccurate!

Compare Fahrenheit, an attempt to avoid any negative temperatures. Soon
rendered pointless by better refrigeration and experience of colder
climates. There's now an absolute solution!

Mike.

[olds...@tubes.com]

Those PF caps were also known as MMFD or as you said, UUFD (usually in
lower case). And yes, electrolytics were usually labelled as MFD, rather
than UF. NF was never used back then, I never even heard of it.

However I am finally making sense of it, even though it's sort of
annoying having to change stuff that I know all too well. But I did
finally figure out that to convert to UF from NF, just move the decimal
point 3 places to the left. Thus a 50 nf cap is a .05uf cap. Which in my
measurements showed the .05uf cap that I measured as 52.6nf. Pretty darn
accurate for a 50 year old paper/wax cap. So, that cap would actually be
a 52.6nf.

So, I now see it's not all that hard to convert, but being someone who
hates mathematics and has always had trouble with math, it's just more
tedious. I did find a few websites that have conversion charts, that
show all common caps in UF - NF and PF. I saved the webpage since I am
not always able to go online. I was hoping to find it in PDF format, or
better yet a converter that could be downloaded and run right on my own
computer without having to go online. But at least I have the saved
webpage in my Electronics folder, which contains everything from PDF
tube manuals, resistor/cap color code charts, common transistor and
diode numbers, tube socket pinouts, wire gauge amperages, power
conversion charts, and lots more.... In the old days I had books for all
this stuff, now I got my desktop computer, and an identical copy of that
folder on my laptop computer for portable use.

(Of course I do still have many of the old books too, but the computer
is easier to use and takes up less space in my shop).

[MJC]

In article <MPG.332b394e4...@news.east.earthlink.net>,
rmower...@earthlink.net says...

stuff and the MFD was for the larger capacitors.
>
> I am not old enough to remember when most all capacitors were called
> condensers all the time. For me most electronics was capacitors and the
> condensers were used across the points of gas engines.

I learnt about condensers. I expect those motor engineers had only just
stopped calling them Leyden Jars! ;-)

Mike.

[analogdial]

Nano is the metric prefix between the familiar micro and pico. I have
no idea why it wasn't used much in the US until the last couple of
decades or so.

It's a little as if we had grown up using only ohms and megohms and then
they started throwing this newfangled "kilo" thing at us. WTF?

[John Robertson]

Speaking of absolute, there is always degrees Kelvin if you want to
avoid negative numbers...

John ;-#)#

--
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[whit3rd]

On Friday, March 10, 2017 at 10:52:43 AM UTC-8, John Robertson wrote:

> Speaking of absolute, there is always degrees Kelvin if you want to
> avoid negative numbers...

Ah, there speaks an engineer! Adiabatic demagnetization (or population
inversion in lasers, for that matter) means physicists have to keep a minus
sign handy, even on Kelvin scales.

OK, physicists run into it; everyone else just reads about it.

[tabb...@gmail.com]

On Thursday, 9 March 2017 07:40:31 UTC, olds...@tubes.com wrote:
> 40 years ago, back when I did a lot with electronics, capacitors were
> either F (farads), UF or MFD microfarads, (UF and MFD were the same
> thing), or PF (Picofarad). Now they are using NF. What the heck is that?

What is all this nuff and puff stuff? These newfangled condensors should be marked with cm. Bring back pith balls.


NT

[Jon Elson]

a pF is 1 millionth of a uF. A nf is 1 thousandth of a uF. So, .001 uF is
1 nF. 1000 nF is 1 uF.

Jon

[rickman]

I'm surprised you are using pF, I would have thought you'd be using uuF.

http://bfy.tw/1vkq

--

Rick C