Download DVD-165C Component Number Codes

DVD-165C Transcript v.1
DVD-165C
Component Number Codes
Below is a copy of the narration for DVD-165C. The contents for
this script were developed by a review group of industry experts and
were based on the best available knowledge at the time of
development. The narration may be helpful for translation and
technical reference.
Copyright  IPC – Association Connecting Electronics Industries. All Rights Reserved.
Introduction
MOVIE NARRATOR
This is the story of the great Sherlock Holmes, and how he solved the
unfathomable mystery of the Component Number Codes! These troublesome
components with their mysterious symbols have compelled trainers everywhere
to inflict boring lectures upon their hapless students. Only the greatest mind of
Scotland Yard had any chance of making these codes comprehensible to
everyone.
HOLMES
See here Watson, it’s really very simple. Each code is expressed by its reverse
counterpart in this series of hieroglyphics that I have especially devised in order
to make these codes understandable to anyone.
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DVD-165C Transcript v.1
WATSON
Wait a second Holmes… is that microhenries or picofarads?
HOLMES
Never mind that… let’s see what you got.
WATSON
“1YZLMTHK…” total nonsense, I’m afraid.
HOLMES
Hmmmm… This may be more problematic than I thought. Why don’t they print
the value on these confounded components?
NARRATOR
Sorry Sherlock, but that only happens on the big components. Most of the
modern components are simply too small to have their complete values printed
on them. In this case, you’ll need to calculate these values by deciphering either
color bands or number codes. To learn component color code calculation, see
the IPC program, DVD-164C.
In this video, we’ll show you how to decipher the numeric codes that are
commonly used on a variety of resistors, capacitors and inductors. In addition,
we’ll offer some guidelines for component substitution. When you understand
these techniques, you’ll be able to take the mystery out of identifying the value
and tolerance for these types of components. That way you’ll always be sure
that you have the correct component for the job.
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DVD-165C Transcript v.1
Resistor Number Codes
HYPNO WHEEL OPERATOR
The hypno-wheel will teach you how to decipher chip resistor number codes.
Focus on the wheel... and relax your mind. For three-numbered chips, the first
two numbers represent the values, and the third number is the multiplier. A small
box symbol or a colon equals the number 8. Any letters such as F or J represent
the tolerance expressed in plus or minus percentages. Now, what have you
learned?
(WATSON SNORING)
HOLMES
Hmmm… there must be an easier way?!
NARRATOR
You really don’t need a hypno-wheel to decipher chip resistor number codes. All
you really need to know is a few basic principles. First, the value of a resistor is
expressed in a unit of electrical resistance called ohms. Next, numeric chip
resistors will typically have three or four numbers that will need to be decoded.
We’ll start with three-digit value codes.
With three-digit value codes, the first two numbers are simply the first two
numbers of the resistor’s value. The third number is called the multiplier – and
determines how many zeros will be added to the first two value numbers. For
example, this chip resistor has a numeric code of one zero one. The first two
value numbers are one and zero, or ten. The third number, our multiplier, is one
– which means we add one zero – making the value of our resistor one hundred
ohms.
Notice there is no code for tolerance marked on the component. Tolerance is a
measurement of how close a component must perform to its actual value. With
most chip resistor manufacturers, components with three-digit value codes have
a tolerance of plus or minus 5% -- and components with four-digit value codes
have a tolerance of plus or minus 1%. When a different tolerance is required, a
letter code that specifies the tolerance will be added at the end of the number
code.
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DVD-165C Transcript v.1
Going back to our 100 ohm resistor, the tolerance is plus or minus 5% -- since
one zero one is a three digit code. 5% is equivalent to point zero five. Point
zero five times 100 equals five. One hundred plus five is 105…and 100 minus
five equals 95. So our tolerance, or operating range is 95 to 105 ohms.
Let’s calculate the value of another three-digit resistor. The first two significant
value numbers are five and zero, or fifty. The multiplier is two – which means we
add two zeros. The value of our resistor is 5,000 ohms, plus or minus 5%. A
5,000 ohm resistor is sometimes abbreviated as 5K ohms. K is short for kiloohm, or one thousand ohms. One thousand has three zeros which can be
replaced by the letter K.
This three-digit resistor has the number code of 605. The first two value
numbers are six and zero, or 60. The multiplier is a five – meaning we add five
zeros. The value of this resistor is 6 million ohms with a tolerance of five percent.
Upper case “M” is the abbreviation for meg-ohms, or one million ohms – and can
replace the six zeros. Therefore, we can also specify the value of this resistor as
6 meg-ohms. And don’t mistake a lower case “m” for an upper case “M”. They
are two different measurements – use uppercase “M” for meg-ohms, or million –
and lower case “m” for milli-ohms, or hundred.
Notice that if the third number happens to be a zero, no zero would be added and
the value would then equal 60 ohms – plus or minus 5%. Like-wise, a chip
resistor with the number code of 330 would indicate a 33 ohm resistor.
Now, let’s examine four digit chip resistors. On four digit components, the first
three numbers are read as value numbers and the fourth number tells you how
many zeros to add. In this example, the number code of 1003 is calculated as
one hundred with three zeros added – giving us 100,000 ohms. Again, we can
replace those three zeros with a K to abbreviate the value as a 100K ohm
resistor. And remember, four digit chip resistors have a default tolerance of plus
or minus 1%.
Let’s look at another example with a number code of five six two two. The first
three value numbers are five six two. Our multiplier is a two – so we add two
zeros – giving us 56,200 ohms, or 56.2K ohms, with a 1% tolerance.
Now that you have a feeling for how number codes work for three and four-digit
chip resistors, let’s take a look at some variables that will slightly modify the
methods we’ve discussed.
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DVD-165C Transcript v.1
We’ll start with the letter “R’ – which you may see at the beginning or middle of a
three-character number code. We use an R to show where a decimal point goes.
The value of this resistor is seven point seven ohms. The reason that R is used
is because we would not be able to see a decimal point on a component this
small. When R is used in a three-character code, there is no multiplier.
In this example, a component reading R47 would be decoded as point forty
seven ohms. And remember, for three character codes the tolerance is still
typically 5% -- the same as a 3-digit code.
On four character codes, R can be at the beginning; between the first and
second numbers; or between the second and third numbers. In this example, the
four-character code is 33R2. 33R2 equals thirty three point two ohms. With four
character codes there will always be three numbers to represent the value – plus
the decimal point. Again, the tolerance on four character code resistors is plus
or minus 1% -- the same as a four-digit code.
To make things even more complicated, the letters K, M or L can be used instead
of R to indicate the position of the decimal point. K is used when the value of the
number code is expressed in kilo-ohms; M for meg-ohms or L for milli-ohms.
For example, a number code of 4K7 would be 4.7K ohms – with a tolerance of
5%. Similarly, K47 would be point 47K ohms. Next, let’s see how upper case M
is used to show the position of the decimal point. Our value here would be 9.5
meg-ohms, plus or minus 5%. Our final example is the number code five one L
zero. Since the letter L represents milli-ohms, the value of this resistor is 51
milliohms. And because this is a four character code, the tolerance would be
plus or minus 1%.
Now that you understand how decimal points can be specified by letter codes,
let’s look at another variable. Most manufacturers use a colon symbol, or two
small boxes to represent the number eight – because the colon takes up less
space than the number eight. In this example, the first two numbers are one and
eight, or 18. Since the multiplier is a three, we add three zeros – giving us
18,000 ohms, with a plus or minus 5% tolerance.
Let’s calculate one more. Our number is two seven colon two. Since the colon is
an eight, our code is 2782. The three value numbers are two seven eight – and
our multiplier is a two – meaning we add two zeros – giving us 27,800 ohms, with
a tolerance of 1%.
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DVD-165C Transcript v.1
Our next variable involves using a letter code for tolerance to the right of the
multiplier number – especially on axial resistors. In this example, the number
code seven oh oh two is 700 with two zeros added for a value of 70,000 ohms.
Using the letter code chart, we see that F gives us a plus or minus one percent
tolerance.
Another example is two five four K. The first two value numbers are twenty five
and the multiplier is four zeros – giving us 250,000 ohms - or 250K ohms. The
tolerance letter code is K – which indicates a plus or minus ten percent tolerance.
Our last variable for resistor number codes involves E-series resistors. The Eseries was created to provide standard component values over a whole range of
tolerances – not just the 5% for 3-digit codes and 1% for 4-digit codes that we’ve
been discussing for chip resistors. Unlike the 3- and 4-digit number codes, Eseries resistors use a 3-character code consisting of two numbers to represent
the value and a single letter to represent the multiplier.
To show you how this works, we’ll examine the alphanumeric codes for oh-sixoh-three, 1% chip resistors. These chip resistors belong to the E-96 series. To
decode these resistors, we’ll use two charts – one to determine the value and
one to find the multiplier.
For example, the marking on this resistor is twelve C. Using the E96 chart for
1% tolerance, we see that twelve has a value of 13 point zero. And using the
multiplier chart, we see that “C” tells us to add three zeros and to move the
decimal point three places to the right. That gives us thirteen thousand ohms, or
13K ohms with a 1% tolerance.
Let’s do one more example. The alphanumeric code on this resistor is 16B. We
see that 16 has a value of fourteen point three. And “B” tells us to add two zeros
and to move the decimal point two places to the right. That gives us one
thousand four hundred thirty ohms – or one point four three K ohms.
Chip resistor sizes such as “oh four oh two” and “oh two oh one” are too small for
any value code marking. And the “oh one oh oh five” size can barely be seen
without magnification. For these types of chip resistors, the only place where
codes for value and tolerance are marked is on the tape reel.
Now that you’ve been introduced to the variables of reading resistor number
codes, let’s do an exercise to make sure that you understand the process. We’ll
start with this 3-digit chip resistor. See if you can determine the value and
tolerance.
Pause the program now and perform the calculation using the 3-digit value code
chart – or use the optional Review Questions if provided.
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DVD-165C Transcript v.1
The answer is 25,000 ohms, plus or minus 5%. Let’s look at how we made this
calculation. The first two numbers are the value – a two and a five – giving us
25. The third number tells us to add three zeros to 25. That gives us 25,000, or
25K ohms. Remember that three digit resistors typically have a 5% tolerance.
Now let’s try a 4-digit chip resistor. What is the value and tolerance of this
component? The answer is 36,700 ohms with a plus or minus 1% tolerance.
Here’s how we got that answer: The first three value numbers are 367. The
multiplier is a two – meaning we add two zeros – giving us 36,700, or 36.7K
ohms. And 4-digit resistors have a 1% tolerance.
Let’s try another calculation with the letter R in the code (67R5). The answer is
sixty seven point five ohms, plus or minus 1%. The important thing to remember
with this calculation is that R tells us the position of a decimal point. When a
decimal point is indicated, there is no multiplier. Tolerance for 4-character codes
remains the same as 4-digit codes – or plus or minus 1%.
What is the value of this chip resistor (7K2)? The answer is 7 point two K ohms,
plus or minus 5%. Remember that K is also a decimal point with the value
expressed in kilo-ohms. And tolerance is plus or minus 5% for 3-character and
3-digit resistors.
Can you figure this one out (7:3)? The answer is 78,000 ohms, plus or minus
5%. The thing to remember in this example is that the colon symbol represents
the number 8 – so we have seventy eight with a multiplier of three, or three zeros
– giving us a value of 78,000 ohms, or 78K ohms. Again, a 3-character resistor
has a tolerance of 5%.
What is the value and tolerance of this axial resistor (2003G)? Here’s how we
decoded this value. Since this is a four-digit number code, the first three
numbers are the value – a 2 and two zeros. That equals 200. The fourth
number tells us to add three zeros to 200. That gives us 200,000, or 200K ohms.
The tolerance code is G. We see that G on the letter code chart specifies a plus
or minus 2% tolerance.
Our last calculation will be for an “oh six oh three” E96 series chip resistor (89D).
Remember, these codes use two numbers to indicate the value from the E96
chart and a letter code to find the multiplier on the multiplier chart. The answer is
825,000 ohms, plus or minus 1%. The way we got that answer was to go to the
E96 chart and find the number 89. We see that 89 has a value of 82.5. Then we
see that D on the multiplier chart tells us to add four zeros and to move the
decimal point four places to the right. That gives us 825,000, or 825K ohms.
Again, the E96 series is for 1% tolerance resistors. That’s all there is to it.
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DVD-165C Transcript v.1
Capacitor and Inductor Number Codes
HOLMES
We need a way to decipher these codes automatically.
FIRST MAN
I’ve got the component scans right here, Chief.
CHIEF
Excellent, let’s have a looksee on the component gradiator.
HOLMES
Hmmmmm….
Inductor, 150 Microhenries
WATSON
Remarkable Holmes. Try another.
HOLMES
Capacitor, 1000 picofarads.
WATSON
That’s amazing Holmes.
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DVD-165C Transcript v.1
HOLMES
What devilry is this?
WATSON
Perhaps the gradiator needs an upgrade?
FIRST MAN
Maybe we should give the hypno-wheel a go.
CHIEF
What say you Holmes?
HOLMES
We’re back to square one, I’m afraid.
NARRATOR
Even without a hi-tech device like the component gradiator, you can still
determine the value of numbered capacitors and inductors. These components
are read in a similar manner as resistors – with some variation for chip
capacitors. The main thing that changes is the unit of measure. Capacitors are
measured in Farads and inductors are measured in Henries. Both capacitors
and inductors use the same letter codes as resistors to indicate tolerance. When
the tolerance is not specified, the default is plus or minus 20%.
Let’s begin with capacitors. As we just mentioned, the value of a capacitor is
expressed in a unit of electrical capacitance called farads. The three most
common units of measurement using farads are microfarads, nanofarads and
picofarads. The picofarad has the smallest capacitance value. For example, one
million picofarads is equal to one thousand nanofarads, or one microfarad.
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DVD-165C Transcript v.1
Like the resistor, the value and tolerance of the capacitor will either be printed on
the component, or can be deciphered by calculating coded numbers into
numerical values.
There are some general rules on how values and tolerance are expressed. The
number coded values of capacitors are calculated in picofarads. On larger
capacitors, the value, tolerance and voltage will usually be printed on the
component. On smaller capacitor bodies, value and tolerance are typically
represented by a 3-digit code for value and a letter code for tolerance. This
surface mount capacitor is also marked with a voltage value of 10 and a numeric
lot code. The three numbers that make up the value code on capacitors are
read the same as chip resistors. Again, the first two numbers are read simply as
numbers. The third number, the multiplier, tells you how many zeros to add to
the first two numbers. In this example, the 4 and the 7 have six zeros added to
them – giving us 47 million picofarads. Unless otherwise printed, the unit of
measurement for capacitors is always the picofarad. 47 million picofarads can
be converted to 47 microfarads. As you can see, there are letters assigned to a
wide range of tolerances. In our example, the tolerance letter code is K. Using
the letter code chart, we see that K represents plus or minus 10%.
Some surface mount capacitors may contain a micro symbol or a lower case “n”
in the first or second position of the number code. The micro symbol lets us
know that the value of the capacitor is calculated in microfarads -- and an “n” tells
us to calculate in nanofarads. The micro or “n” also indicates the position of a
decimal point – much in the same way that R, K or M did for resistors. The
value of this capacitor would be point sixty five microfarads. Since there is no
code specified for tolerance, tolerance will be plus or minus 20%. In the second
example, we have the code 6n5. The value of this capacitor is 6 point 5
nanofarads.
Some chip capacitors use a 2-digit alphanumeric code – with a letter
representing the value and the number being the multiplier. In this example, our
2-digit code is F4. The letter chart specifies values for all of the upper case
letters except i and o – and nine of the lower case letters. In the example, upper
case F equals one point 6. The multiplier chart tells us how many zeros to add to
the value number. Since the multiplier is a four, we add four zeros to one point
six and move the decimal point four places to the right. As you can see, the
result is 16,000 picofarads. The default tolerance is 20%.
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DVD-165C Transcript v.1
Let’s try one more of these. Our 2-digit alphanumeric code is lower case n2.
Looking at the letter chart we see that small n represents a value of seven point
zero. And the number 2 – from our multiplier chart – tells us to add two zeros
and move the decimal point two places to the right – giving us 700 picofarads –
with a 20% tolerance.
It is rare for the smaller chip capacitors to have any type of value indications on
them. The actual value or a numeric code will be printed on the tape reel in
which the chip capacitors are packaged.
Now that you understand how to calculate the value of capacitors using several
systems of number codes, let’s do an exercise to make sure that you understand
the process. We’ll start with this 3-digit, single letter code capacitor. See if you
can determine the value and tolerance. The answer is 700,000 picofarads with a
five percent tolerance. Let’s see how we made this calculation. The first two
value numbers are seven and zero. Our third number is a four – so we add four
zeros. That gives us 700,000. 700,000 picofarads can be converted to 700
nanofards or point seven microfarads. Our letter code for tolerance is a J –
which gives us plus or minus 5%.
Now, let’s try another (3µ5). The answer is three point five microfarads with a
20% tolerance. Remember that the micro symbol not only tells us that our value
will be in microfarads, but it also tells us the position of the decimal point. In this
case the decimal point is placed between the three and the five giving us 3 point
5 microfarads. Since the tolerance is not specified, it is assumed to be plus or
minus 20%.
Let’s try one more. This time we’ll make our calculation from a chip capacitor
with a 2-digit alphanumeric code (U2). Use the letter and number charts to see
if you can make the calculation. The answer is 560 picofarads, with a tolerance
of 20%. Here’s how we got that answer. The first step is to find upper case U on
the value letter code chart. The value of U is 5 point 6. Next, we go to the
multiplier chart and find the number 2. The number 2 tells us to add two zeros
and to move the decimal point two places to the right. That gives us 560
picofarads. Again, tolerance wasn’t specified so we default to 20%.
Now that we’ve examined capacitor number codes, let’s turn our attention to
inductors. Inductors are measured in henries and micro divisions of henries. nH
stands for nanohenry, micro H or uH stands for microhenry – and mH represents
milli-henry. One million nanohenries is the same as one thousand microhenries,
or one milli-henry. Number coded inductors are almost always calculated in
microhenries.
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DVD-165C Transcript v.1
The number codes used for inductors are the same as the basic codes for
resistors and capacitors. Almost all number coded inductors are the 3-digit
variety. When tolerance is specified, we use the same letter code conventions
as we did for resistors and capacitors. Otherwise, tolerance is assumed to be
plus or minus 20%.
In this example, our radial inductor has a 3-digit single letter code of two two
three C. The first two value numbers are twenty two. The multiplier is a three –
meaning we add three zeros. That gives us a value of 22,000 microhenries. The
tolerance letter code is C. Using the tolerance letter code chart, we see that the
tolerance is plus or minus point two five percent.
If there is a decimal point, it is indicated by the upper case letter "R" or “K”. Like
three digit decimal codes for resistors, the R or K would be at the beginning or
middle of the numbers. For example, 9K7 would be decoded as 9 point 7
microhenries. Remember, when a decimal point is indicated there is no
multiplier. The default tolerance is 20%.
Now, let’s see what happens when the value is too small to be expressed in
microhenries. In this case, the decimal point would be represented by the letter
N – meaning the value would be specified in nanohenries. For example, the
number code 7N5 would designate a value of 7 point 5 nanohenries. Again,
tolerance is 20%.
Now that you understand how to calculate the value of inductors, let’s do a
couple of practice calculations. We’ll start with this 3-digit, single letter code
surface mount inductor (151K). See if you can determine the value and
tolerance. The answer is 150 microhenries with a 10% tolerance. Here’s how
we got that answer. The first two value numbers are a one and a five, or 15 –
and the multiplier is a one – which means we add one zero to 15. That gives us
150 microhenries. The tolerance letter code is a K – which specifies a tolerance
of 10%.
Let’s do one more. What is the value and tolerance of R eight seven? The
answer is point eighty seven microhenries, with a 20% tolerance. Remember
that R tells us the position of the decimal point and our two numbers of eight and
seven gives us a value of point eighty seven. Again, there’s no multiplier digit –
and since tolerance is not given, we default to 20%.
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DVD-165C Transcript v.1
Substitutions
MOVIE NARRATOR
Dartmore prison. Isolated from the outside world by walls of granite.
PRISONER 1
Hey, spiffy polish on these wooden I-Phones, mate. So, what ya in for, anyhow?
PRISONER 2
I substituted a 9-ohm resistor for a 9-kilo-ohm resistor.
PRISONER 1
Well, that don’t sound so bad…
PRISONER 2
Oh yeah, ever hear of Apollo 13?
GUARD
Back to work, or it’s the hypno-wheel for you blokes!
NARRATOR
Our final topic involves component substitutions. There may be times when the
component we need to make a repair with is out of stock. If this is the case, it
may be appropriate to substitute a component with similar characteristics. And if
you don’t want your assemblies to end up like the ill-fated Apollo mission, always
refer to your company policy for substituting components. Be aware that some
companies never allow substitutions. When substituting voltage, wattage or
tolerance, check the Bill Of Materials for the complete description of the
component. It’s important to realize that exact matches are not always
necessary. Here are some general rules for substituting components.
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DVD-165C Transcript v.1
Voltage can be substituted with a higher voltage but not lower. Voltage is the
potential energy that makes electricity flow in a circuit. For example, if the bill of
materials calls for a 50 volt component – a 100 volt component could be
substituted in its place. If a 100 volt component was substituted, that would be
acceptable because the component can handle up to 100 volts. It would be
unacceptable if a 25 volt component were substituted instead. If 50 volts were
applied to a component rated for 25 volts, the component would not function
properly and would likely be damaged.
The same rule applies when substituting wattage. To substitute a resistor rated
at one quarter watt, you would need to use one that would be capable of
receiving a higher wattage – say one half watt – rather than lower, or one eighth
watt.
Another substitution may involve tolerance. Unlike voltage and wattage that
substitute using higher numbers, when it comes to substituting tolerances, you
must use a component of the same value with a lower tolerance. The lower
tolerance is a more controlled and precise component. For example, the bill of
materials description calls for a 5% tolerance. An acceptable substitution is with
a tolerance of 1%. One percent is considered a precision part. The operating
range is narrow and more controlled – so it is acceptable to use a 1% tolerance
in place of the 5%.
This program has presented the details of how to accurately decipher component
number codes. We’ve also demonstrated how to calculate the value of resistors,
capacitors and inductors.
There’s been a lot of information presented – and you certainly don’t need to
remember it all. All the information you need to decipher number and letter
codes is printed on the charts. What is important is to be able to understand and
use the methods shown in this video.
By learning and understanding how to translate the number codes, you can take
the mystery out of identifying the value and tolerance of number coded
components.
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DVD-165C Transcript v.1
WATSON
What do you say, Holmes? Have we solved the mystery of the component
number codes?
HOLMES
That all depends, old boy. We won’t know for sure until the students take their
bloody exam!
WATSON
In any event, I’ll certainly miss the hypno-wheel at naptime
.
HOLMES
Not to worry Watson, I’m sure this video can put you to sleep just as well! I
consider this case closed.
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