4k7 means 4700 ohm right?
- Thread starter MadsT
- Start date
westaust55
Moderator
For some further clarification
To simplify the writing of large resistor values, the abbreviations K and M are used for one thousand and one million. To keep the convention standard, R is used to represent 0. Recently L was also added for milli.
Because of problems in seeing the decimal point in some printed texts, the letters: M, K,R or L are used in place of the decimal point. Thus, a 2,700 Ohm resistor is written 2K7 and a 6.8 Ohm resistor is written 6R8.
The same convention applies across other components and units as well, so:
0R15 = 0.15 Ohm
330R = 330 Ohms
4k7 = 4.7k Ohms, 4,700 Ohms
6M8 = 6.8M Ohms, 6,800,000 Ohms
4L7 = 4.7 milli Ohm (eg current shunt)
1V6 = 1.6Volt
2n2 = 2.2nFarad
4u7 = 4.7uFarad
To simplify the writing of large resistor values, the abbreviations K and M are used for one thousand and one million. To keep the convention standard, R is used to represent 0. Recently L was also added for milli.
Because of problems in seeing the decimal point in some printed texts, the letters: M, K,R or L are used in place of the decimal point. Thus, a 2,700 Ohm resistor is written 2K7 and a 6.8 Ohm resistor is written 6R8.
The same convention applies across other components and units as well, so:
0R15 = 0.15 Ohm
330R = 330 Ohms
4k7 = 4.7k Ohms, 4,700 Ohms
6M8 = 6.8M Ohms, 6,800,000 Ohms
4L7 = 4.7 milli Ohm (eg current shunt)
1V6 = 1.6Volt
2n2 = 2.2nFarad
4u7 = 4.7uFarad
A common mistake is to use 'K' for kilo. The kilo is designated using a 'k'.
'K' stands for degrees Kelvin. A temperature measurement!
Interesting. Didn't know about that one. Why not use 'm', as in 4m7? Haven't seen it used.
westaust55
Moderator
Yes I do make typos from time to time and do try and fix most that I spot even if a bit later in terms of spelling.A common mistake is to use 'K' for kilo. The kilo is designated using a 'k'.
'K' stands for degrees Kelvin. A temperature measurement!
Interesting. Didn't know about that one. Why not use 'm', as in 4m7? Haven't seen it used.
Virtually all resistor manufacturers (have a look at Vishay, IRC and Welwyn for example) use a capital K when using the letter "amongst the digits" more as a "code" than a prefix.
Vishay on their datasheets for example will state 4K7 = 4.7 k ohms - all very correct when we consider the 4K7 is a form of code.
likewise R is not an SI multiplier but is used along with L in the resistor industry, both as upper case in the "coded" sense of component value.
But yes, by ISO 1000, lower case "k" is correct for kilo.
When writing out values and units, in compliance with ISO 10000, we should also note that:
Unit symbols shall be printed in roman (upright) type (irrespective of the type used in the rest of the text), shall remain unaltered in the plural, shall be written without a final full stop (period) except for normal punctuation, e.g. at the end of a sentence, and shall be placed after the complete numerical value in the expression for a quantity, leaving a space between the numerical value and the unit symbol.
Unit symbols shall in general be written in lower case letters except that the first letter is written in upper case when the name of the unit is derived from a proper name.
Unit symbols shall in general be written in lower case letters except that the first letter is written in upper case when the name of the unit is derived from a proper name.
I do try to follow this in terms of upper and lwoer case and a space between the numeric and units parts but admit I do fail to comply from time to time.
Oh and with respect to:
when using the kelvin units of temperature measurement,
1. kelvins are the increment not degrees, and
2. "kelvins" use a lower case "k" when written as the word
so we can write/say that 0 kelvin = −273.15 degrees Celsius
If we refer to the thermal scale then yes use a capital "K" for the "Kelvin scale".
Don't worry Westy, we all make mistakes.
Sometimes we even call them typoes
But moving on from the not-to-be-outdone Beat Your Neighbour compo, I would have thought that if you saw a resistor or pack with 4K7 or 4k7 on it then you'd have a pretty shrewd idea what it meant. Context being quite significant.
And gosh you chaps have been busy with Google.
We haven't mentioned the marking convention often seen on SMD resistors - we desparately need some clarification on that too.
Sometimes we even call them typoes
But moving on from the not-to-be-outdone Beat Your Neighbour compo, I would have thought that if you saw a resistor or pack with 4K7 or 4k7 on it then you'd have a pretty shrewd idea what it meant. Context being quite significant.
And gosh you chaps have been busy with Google.
We haven't mentioned the marking convention often seen on SMD resistors - we desparately need some clarification on that too.
Quite - I have one batch of 10K marked with "1002" and another batch marked with "103". How confusing is that
inglewoodpete
Senior Member
So if I see a 4.7K resistor, it will be really, really cold?
Not half as confusing/worrying as the totally blank smd caps.
A lot of trust is required.
Did the factory put them in the right boxes?
Did the spotty schoolboy at Farnell put them in the right drawers?
Did the picker put the right ones in your Jiffy?
Did someone knock all the drawers over and put them back correctly?
followed by...
Oh damn I've just dropped my capacitor box.
Gosh, we're going to have fun measuring 12pF...
If you can get printed packing tape then why oh why can't these people print the bandolier/cassette/tape at the very least?
A lot of trust is required.
Did the factory put them in the right boxes?
Did the spotty schoolboy at Farnell put them in the right drawers?
Did the picker put the right ones in your Jiffy?
Did someone knock all the drawers over and put them back correctly?
followed by...
Oh damn I've just dropped my capacitor box.
Gosh, we're going to have fun measuring 12pF...
If you can get printed packing tape then why oh why can't these people print the bandolier/cassette/tape at the very least?
Seemingly so brrrrr
westaust55
Moderator
Exactly what I do for myself - usually while still within the store if I am buying locally
fernando_g
Senior Member
You have hit a raw nerve without anestesia.
It gets worse with SMD diodes and transistors. All they have printed on their bodies is this three letter code, which then you have to figure out (if you know the vendor) exactly what it means.
The problem becomes worse with devices which are produced by different manufacturers. For instance, the BAT54x schotky diode which comes in a SOT23 package. The BAT54x can have an A,B,C suffix, depending whether it is a single device or a dual device with common anode or common cathode configurations.
Well, I found instances where these configurations are coded differently with two different vendors. Causes lots of confusion.
Agreed. Makes reverse engineering someone else's design from just a PCB much harder
Minifig666
Senior Member
ISO 1000 is outdated Westy, try the ISO/IEC 80000
http://en.m.wikipedia.org/wiki/ISO/IEC_80000
http://en.m.wikipedia.org/wiki/ISO/IEC_80000
westaust55
Moderator
Thanks for that snippet Minifig666
Seems that the Aust Standards Association is falling a little behind.
When I look thru our local standards office (SAI Global), I see that:
IEC 80000 Parts 6,13 & 14 were released in Mar 2008
ISO 80000 Parts1, 2 & 10 were released in Nov 2009.(and other parts at varying dates).
BS ISO 80000 Part1 and many other parts came out in Jan 2010.
I note that seemingly where there is an IEC part (ie 6,13 and 14) there is no corresponding ISO part(number). So done in collaboration not parallel documents or duplicaiton.
But as at June 2010, from the Australian Standards Assoc., AS ISO 1000 is still the most current here in Australia.
Some times, things just take time to officially filter down under.
Seems that the Aust Standards Association is falling a little behind.
When I look thru our local standards office (SAI Global), I see that:
IEC 80000 Parts 6,13 & 14 were released in Mar 2008
ISO 80000 Parts1, 2 & 10 were released in Nov 2009.(and other parts at varying dates).
BS ISO 80000 Part1 and many other parts came out in Jan 2010.
I note that seemingly where there is an IEC part (ie 6,13 and 14) there is no corresponding ISO part(number). So done in collaboration not parallel documents or duplicaiton.
But as at June 2010, from the Australian Standards Assoc., AS ISO 1000 is still the most current here in Australia.
Some times, things just take time to officially filter down under.