Episode: 3454
Title: HPR3454: Engineering Notation
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr3454/hpr3454.mp3
Transcribed: 2025-10-24 23:43:27

---

Hi everybody, my name is Ken Fallon and you are listening to another episode of Hacker
Public Radio.
Following the one from Platuz, phonetic alphabet in episode 3087, which is kind of required
for ham radio operation and it's also very useful for if you're on the phone to somebody
from another country and you want and the line is bad, it's always very good to have
a standard abbreviation for words that you can spell out what you're trying to say.
In this show, we're going to do another one that you're going to need to learn for your
ham radio exam, but also in general, it's good to know for various different things.
So you get an idea of what quantities are and that's engineering notation.
So the quantities are actually a list of international SI units.
If you go there, there's a lot of definitions for what they are.
So we're not actually talking about weight or length or anything else here.
We're talking about the names that we give to those numbers associated with.
So we might have a kilo meter, that's, we're talking about the k part and not the meter
part.
So we're talking about a kilo gram, we're talking about the weight, we're not talking
about the weight, which is the gram part, we're talking about the prefix before that the
kilo.
Okay, so that's what we're going to be talking about in the show.
And all I'm going to be doing is multiplying by a thousand and dividing by a thousand.
No, another way of putting saying that is when you're multiplying your adding zeros and
when you're dividing, you're taking away zeros, that's very, very simple, very, very
simple.
And there's a few ways of writing this down.
You can write it down with the actual numbers.
So a kilo would be one zero, zero, zero.
So it's a thousand in common parents.
But the problem with writing it down like that, that's actually fine, is that once you
get very big numbers, very small numbers, the number of zeros becomes very, very difficult
to work with.
So we don't tend to do that.
With engineering notation, we take the assigned numbers and instead of having all of them,
we just use every thousand.
So orders of three, so the zero, we either add three zeros or we take away three zeros.
So we don't have to learn the in-between ones like decimator or centimeter.
We jump straight up in threes.
So that makes life simpler because engineers are simple people and simpler people are
even hampily do our pressures who are only interested in the range that's of interest
to them.
Now you'll find in some cases you're talking about, it's very, very small numbers and in
some cases you're talking about very, very large numbers.
So here we're going to be talking about three big numbers and essentially four small
numbers.
Okay, so that's what we are, that's where we are.
If you have any familiarity at all with the metric system, you're going to kind of know
the first ones, especially if you're doing anything with computers, you're going to
know the first three ones.
So we started zero and we go up, we multiply zero by a thousand, we'll add three zeros
behind the one, sorry we'll add one and we'll add three zeros behind the one and that
will give us one thousand which is also known as a kilo kilo and the abbreviation for that
is K.
So if you're in Europe and you go in and you buy some coffee, you might get a kilo of
coffee, so one K and that will be a kilo gram, so one KG, okay, so kilo, lower case letter
K, the case of the letters unfortunately is important, so you're going to need to remember
those that it's a lower case K.
Now when you're talking about writing these down in forms, it's not very handy to write
the case because the letters, because people's handwriting are terrible, so what we normally
do is we write a suffix with a number of what it is to the power of 10.
Now this is not the correct definition but it's a very good way to remember is the number
in the suffix is the number of zeros behind the one or behind the number that you're dealing
with, so in this case we're talking about one one thousand and so forth, but it might
be three point two thousand, yeah, so there we go.
Now where are we, yeah suffix, so if you've never, if you've never come across that before
that's you have the number, so you write ten normally one and a zero and then you write
where you would normally put the next letter, you write a small character three about half
the size, half the size of the main character and resting half way up the top of the letter,
so a kilo would be abbreviated to K and it would be ten to the power of three, so that's
what that power of three and that means you take ten, you take whatever number it is
and you multiply it by a thousand, three zeros.
So the next one up we go three more up and guessed it it would be equivalent to the million,
so one with six zeros afterwards and that's called mega and the abbreviation for that
you guessed it is a capital M, so a big M and the suffix for that is we have six zeros,
so it's ten to the power of six, so big ten and a small six.
Okay, ready brace yourself now and we'll go up another multiply it by a thousand again
and we get giga, so giga and the abbreviation is G, the big letter capital letter G and
the suffix is we've added three to six, so what it was going to be, it's going to be nine,
so it's a nine.
I won't give you what that's called because there's different definitions of that,
so that's not useful to us, so ten to the power of nine is giga, ten to the power of six is mega,
ten to the power of three is kilo, so we're done, yeah, okay, now excuse me when I just have a
t, now we'll go back down and the ones we're going to case are milli, micro, nano and picot,
okay, and what that, what we do there is we divide by a thousand, so what happens is we add
three zeros, but this time it's zero dot zero zero, so we add a zero to, we shift the one over,
so a milli is zero point zero zero one, so milli is zero point zero zero one, so that's a milli,
and how do we do that, so the abbreviation course for that is M, so unlike the mega,
which is ten to the power of positive six, it is a lowercase M, and the lowercase tells you
it's a small number, and it's ten to the minus three, so you write big ten, and then up at the top,
where you write the next letter, you write a small minus three, so ten to the minus three means zero
dot zero zero one, so zero period zero zero one, okay, and the next one, we just move everything over
three places again, and we get the micro, which is a bit like a you, the symbol for it is a you,
but on the left hand side the tail goes down, so it's just like as if you start to write a p,
but then it turned into a you, that's what a micro symbol looks like, quite often you'll see it
written with just the letter u instead of micro, so micro is ten to the power of minus six,
so zero point zero zero zero zero zero one, so that's micro, moving on, we divided again by
nano, which is simply the letter n for now, lowercase letter n for nano, and that is ten to the minus
nine, ten to the minus nine, so it's zero dot zero zero zero zero zero zero zero one, okay,
and then the very last one is again, divided by a thousand, we get pico, so pico ten to the minus
twelve, ten to the minus twelve is pico, and yeah, lots of zeros, and then three zeros three zeros
three zeros zero zero one, so it's very useful to remember these, now you're going to get confused
and a lot of the questions that I've seen coming up in the Netherlands, Ireland, and the UK at
least has been trying to trick you out on various different aspects of this, so if you're doing
the ham radio exam, you're more than likely going to come across some question where one element of it
is to identify the various different values, so Bob has something something something complicated
blah blah blah blah, but essentially the answer is what sort of order are we talking about what order
and magnitude are we, so obviously if you're out if you put down your answer of one kilo
and the answer is giga, you're out quite a lot, yeah, so this is kind of important, what I
would advise you to do is on the day of the exam, if you can remember this is great, congratulations
move on, I have trouble with some of this, so what my advice to you would be on the day of the
exam, when you get your paper, the examiners will check your blank paper or on the if it's a written
examin, we'll get to your written exam, what you write, go ahead and when they say okay you can
you can write down stuff and this is perfectly valid in most exams when you get the paper then
you can start writing down your formulas if that's required and writing down these tables, so the first
thing I do in my exam, my exams has been to go in and write down the first one is I write down
as nano because it's nine, nano, nine, nano, nine, nano, nine, so that one I know, nano, nine is
minus nine, 10 to the boroughs minus nine, okay great, then I get I know that pico is smaller than
nano, so that's 10 to the minus 12, okay, so I got two of them done, then I go back up, I know
micro is smaller than milli, so micro has to be minus six, milli has to be minus three and then
the rest I know because three is kilo, six is mega and nine is giga and you're sorted, okay, so
that's your homework for next week, your phonetic alphabet, three, episode 3087 phonetic alphabet,
a good trick to be doing there in your daily life when you board, just read out a sign and pretend
you're reading that out, so this is kilo echo november, fox shot, alpha, lemma, lemma,
I'll score november, in actual fact I'm p papa alpha seven kilo echo november is signing out seven