×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Micros, Picos, Farads, Coulombs etc
5

Micros, Picos, Farads, Coulombs etc

Micros, Picos, Farads, Coulombs etc

(OP)
Please could someone tell me the basic numerics to general electrical terminology, i'm rather at the beginning and i know not a lot of electronics...:)

RE: Micros, Picos, Farads, Coulombs etc

2
kilo 1000 =(10e3)
Mega 1,000,000 =(10e6)
Giga 1,000,000,000  =(10e9)

milli 1/1000 =(10e-3)
micro 1/1,000,000 =(10e-6)
nano  1/1,000,000,000 =(10e-9)
pico  1/1,000,000,000,000 =(10e-12)
femto 1/1,000,000,000,000,000 =(10e-15) (not much used)

Farad = unit of electrical capacitance. Very large. Normal capacitors are in the range 1pF to 10mF (millifarad) ish.

Henry = unit of electrical inductance (coils). Values are nH to H. (nanoHenries for very small uhf coils, H for big iron cored coils & transformers).

Ohms = unit of electrical resistance. Goes from milliohms to Gigohms.

Coulombs - unit of electrical charge.

Volts - unit of electrical potential difference. goes from uV (microVolts) to MV (MegaVolts).

How's that for a start.
rgds
Zeit.

RE: Micros, Picos, Farads, Coulombs etc

Just to follow up on Zeit’s excellent response,

what out for mF.

Older textbooks, and even some modern manufacturers, mean microfarads. That is remarkably incorrect but has been done and you can still find this usage.

The correct form of microfarad is µF but since older systems had a hard job inserting the Greek character mu (ALT 0181 in Windows) they used u instead. Thus you will see people saying things like 10,000uF. They could have said 10mF using the standard form, but everyone knows that mF is a bit ambiguous because of its dubious past!

RE: Micros, Picos, Farads, Coulombs etc

I forgot Amps: goes from pA (picoAmps) to MA (MegaAmps).


If you're a low current electronics engineer like me, anything much above about 30V and 10A gets frightening.

And Hertz,  a measure of frequency, used to be called Cycles per second, which is self explanatory.

Goes from minute fractions of a Hertz (Hz) to GigaHertz and above.

Eventually, it turns into light & X rays & stuff, but that's physics.

rgds
Zeit.

RE: Micros, Picos, Farads, Coulombs etc

I must say that I admire the way zeit and log dealt with this question. I found it utterly difficult to answer in a concise and still useful way. I even thought that it was some kind of a joke. But, given these answers, I realise that the question needed to be put and also to be answered. BTW Zeit; bist du deutsch?

RE: Micros, Picos, Farads, Coulombs etc

O.K.

I thought LONG AND HARD about including this reply. But here goes anyway.

In college, we EEs used to make a semilogarithmic chart for the
mechanical engineers to convert from cycles per second to hertz.......

Just so we don't confuse anybody in this day and age,
1 cycle per second = 1 hertz

But the graph looked interesting and it took them awhile
to get it.

RE: Micros, Picos, Farads, Coulombs etc

One could the add, that frequency f can be converted to time of period ( t= 1/f )

and wavelength (Lambda = s/f) (sorry no Greek keyboard here

where s is the speed of light c (roughly 3e8 m/s) for electromagnetic waves in vacuum (or air).

If not dealing with electromagnetic waves (acoustics, seismic etc.) or if you are not transmitting throgh vacuum  (cables for instance) you will need other values for s.

When going into the light end of the electromagnetic spectrum you usually use wavelength instead of frequency.

RE: Micros, Picos, Farads, Coulombs etc

Not German, Welsh.

Cymru am Byth and all that.

rgds
Zeit.

RE: Micros, Picos, Farads, Coulombs etc

(OP)
Many thanks to all who answered.  I've printed your posts and now all I have to do is figure 'em out! :) I think I may need to rehash my maths from many moons ago!

Jo

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources