Capacitor question. uf and MFD

[hotrodjohn71]

Hi group.

I seem to be getting conflicting results in my research.

If I have a capacitor thats 250 MFD and 16 vdc, will a 250 uf 16dc be the same for replacement?

Some places seem to state that uf is the same as MFD, but some say not.

What do you think?

Thanks,
John

 

[mbarazeen]

As far as i observed uf and MFD are used interchangeably. if you see physical size or mechanical dimensions of both to be similar, no worries. if MFD is referred to be milli farad, then the size should be 1000 times large.

 

[hotrodjohn71]

Thank you. I appreciate it. It was these two searches that confused me because I am looking for

a replacment for an old 250MFD 16dcv capacitor.

 

[rjenkinsgb]

The AI is incorrect.

MFD is old (and inaccurate) terminology, from decades ago, used to mean Micro FaraD.
"uF" in other words.

"mF" is the correct form for milli Farads (1 mF = 1000 uF), but that has only started being more widely used fairly recently, due to the old and wrong M for micro terminology.

 

[Diver300]

It's a font problem.
Micro is correctly abbreviated with "μ", which is the lower-case mu, the greek letter. "u" is often used instead, without much risk of confusion.

If capital letters are all that are available, "M" is all that can be used.

 

[Nigel Goodwin]

As I understand it, mfd was the usual American term for uF, so it's the same thing, as already pointed the actual correct term is actually μF, but uF is usually used as it's much easier to type.

 

[hotrodjohn71]

Thank you fellas.
I greatly appreciate your help.
John

 

[alec_t]

As an aside, to confuse things even further, M denotes Mega (a multiplier of 1 million) in other areas of electronics.

 

[schmitt trigger]

As I understand it, mfd was the usual American term for uF, so it's the same thing, as already pointed the actual correct term is actually μF, but uF is usually used as it's much easier to type.

I am old enough to remember schematics with capacitors labeled mmF or uuF, in lieu of pF.

Of course, back then the frequency was also labeled CPS, instead of Hz.

 

[schmitt trigger]

The scale from an old radio I have got.

 

[schmitt trigger]

And an electrolytic capacitor

 

[Tony Stewart]

If any caps were 250 mF 16V meaning 0.25 F, they would be large
e.g. 2"D x 5.6" L and cost $125 minimum.

If shown as mfd or MFD or uF read as Micro-FaraD. The proper designation uses Greek mu, μ , which was not in the font or character menu when these were made. So lower case U is acceptable these days for uF
and only mF is milli-farad , never MFD.

AI is like a grad student, with a high error-rate on drawings with false assumptions and needs supervision.

 

[Lightium]

Not a day goes by that I don't see errors amoung the major distributors.

 

[starLED]

They can print whole logo Mallory with line, but they can't put simple µ.

 

[DerStrom8]

The use of MFD generally predates the adoption of the SI prefix mu (μ) symbol, often simplified with a u, to mean "micro", or "1 millionth" or "1/1000000". This adoption happened somewhere around 1960. MFD can be found especially on schematics from before then, and always means "microfarad".

Nowadays, we use the following SI prefixes most often:

p (pico, or 1/1,000,000,000,000), n (nano, or 1/1,000,000,000), μ (micro, or 1/1000,000), m (milli, or 1/1000), k (kilo, or 1000), M (mega, or 1,000,000), G (giga, or 1,000,000,000), and T (tera, or 1,000,000,000,000).

There are many more besides these (including centi for 1/100, deci for 1/10, deca for 10, and so on and so forth) but in the electronics field you will more often find the ones listed above.

If you don't take context into account, it may be easy to confuse μ/micro, m/milli, and M/mega.