Tek-Tips is the largest IT community on the Internet today!
Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!
-
Congratulations TugboatEng on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!
Micros, Picos, Farads, Coulombs etc 5
- Thread starter joscott
- Start date
-
2
- #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.
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.
-
1
- #3
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!
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!
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.
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.
Skogsgurra
Electrical
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?
-
1
- #6
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. ;-)
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. ;-)
-
1
- #7
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.
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.
- Thread starter
- #9
- Status
Similar threads
- Locked
- Question
- Locked
- Question
- Locked
- Question
- Locked
- Question