Engineering Notation
The study of electric circuits is really an engineering exercise and not a science. However the knowledge of
circuit analysis is essential to the study of the physics of an electric circuit. So it makes sense for us to know
how to analyse a circuit before we move on to our study of the physics of electric circuits.
Since this is engineering, let's use engineering terminology. The most basic is called Engineering Notation. This
is a way to represent numeric data and is really just a modification of scientific notation:
Metric Prefix
Metric Symbol
Power of Ten
tera
T
10
giga
G
10
9
mega
M
10
6
kilo
k
10
3
unit
none
10
0
12
milli
m
10
-3
micro
µ
10
-6
nano
n
10
-9
pico
p
10
-12
The primary difference between engineering and scientific notation is that engineering notation only uses
multiples of 3 for the power of ten notation exponent, allowing the use of the above defined prefixes to replace
the power of ten notation values altogether. To use the defined prefixes requires a modification to the rules we
used for scientific notation. The exponent needs to be kept at multiples of 3, which means the numbers to the
left of the decimal point has to be in the range of 1 to 999. Once we have converted a number to engineering
notation form, the power of ten will be a multiple of 3 and the numbers to the left of the decimal point will range
between between 1 and 999 to be in proper form. The number of digits to the right of the decimal point will
depend upon how many significant digits we are using. As an example:
10345 = 10345 × 100
= 10.345 × 103
= 10.35 × 103 (4sig.figs.)
= 10.35k
Notice how much easier it is to say "ten point three-five k", instead of "ten thousand three hundred and fortyrd
five" or "ten point three-five times ten to the 3 power."
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Examples using electrical units:
0.0003325 A = 0.0003325 × 100 A
0.225v = 0.225 × 100 v
= 332.5 × 10−6 A
= 332.5 µA
= 225 × 10−3 v
= 225mv
1234.22 × 10 4 W = 12.3422 × 106 W
= 12.34 × 106W
= 12.34MW
Check for Understanding
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Use a piece of scratch paper and convert the following numbers into proper engineering notation form: (round to
the indicated accuracy)
15,000 volts
(2 s.f.)
15,030,000,000,000 watts (5 s.f.)
0.002549 amperes
5
2.357 x 10 ohms
-2
9.81 x 10 amperes
(3 s.f.)
(4 s.f.)
(3 s.f.)
For more information on scientific & engineering notation, try downloading and reviewing this exercise:
www.dlsweb.rmit.edu.au/lsu/content/3_MathsEssentials/maths_pdfs/scientific%20notation.pdf