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Unformatted text preview: Cairo University
Electronics and Communications Engineering Technical English, Lecture 6:
Technical writing Hossam A. H. Fahmy © 2006 Numbers Numbers are important in technical documents.
0 Be accurate. — “The forward bias voltage of a diode is small.” (How small
is small? Should it be the voltage across the diode?) — “Digital disks are better than the analog ones." (In what?
By how much?) 0 Compare the same dimensions. “The value of R, is twice that of C.” 0 Use a small space to separate groups of three digits in a number:
123 456 and not a comma 123, 456. 0 Insert a ‘0’ before the fractional point for numbers between 1
and 1: 0.53 not .53. Objects, properties, and values Watch out for the diﬁerence between a resistor and a resistance,
a capacitor and a capacitance. A resistor is soldered, a resistance is measured, and the value of the resistance is 470 ohms. Additions Parallel work adds in one sense but not the other. Two students
working together on a project for a week 0 produce more work than another student working alone for the
same week, but 0 each gets a work experience of one week not two! Zero and inﬁnity In calculations, engineers often neglect some terms if they are much
smaller than other terms. These are “zeros” while very large terms
are “inﬁnities”. 0 Remember that in reality these are not the mathematical zero
or inﬁnity. 0 In a lab measurement or in a simulation, you will never have a
zero or inﬁnity. 0 If you report a result below or above the range of your measuring
instrument, you may write “Um”, is less than 0.2 mV’7 but do not
say that it is zero. How do we write numbers? In general, single digit numbers (zero through nine) are spelled out7
while numbers of two or more digits (10, 20th Century, use ﬁgures.
Exceptions: 1. Use ﬁgures for all numbers when there are numbers of two or
more digits for related quantities in the same sentence , such as
“6 of 23 physicians recommend”. 2. Use ﬁgures when a unit of measurement follows: “5 A”. 3. Spell approximate values and do not abbreviate the unit (if any):
about ﬁve years, two orders of magnitude, about four times
larger, several kilovolts, and a few tens of megahertz. 4. Use ﬁgures when mathematical operations are implied: factor
of 2 and 3 x 3 matrix. . Spell a number at the beginning of a sentence otherwise rewrite
the sentence. Cr! Watch your units 0 All values that have dimensions must have their units speciﬁed. 0 When written out (not abbreviated), all units start with a small
letter: ohm, volt, and hertz. 0 When abbreviated, units after the name of a person have a cap
ital ﬁrst letter: Hz, V, A. 0 Only multiplier preﬁxes of 106 or more have a capital letter.
Watch out for the difference between A! 2 10+6 and m = 10—3. 0 A nonbreakablc space is required between the value and the unit.
Write 5 kHz and not 5kHZ. 0 Table heading or graphs should be labeled as kV or mV but not
volts X 10’3. o The ‘M’ and ‘G’ in computer memories and drives are currently
ambiguous. Specify what you mean. 8
Equations
The power, P, dissipated in any twoterminal device is
given by
P : I V (1)
where I is the current in the device and V is the voltage
across the device. For the special case of a resistor, the re—
lation between voltage and current can be used to express
the power as a function of only voltage:
v2
P = —. 2
R < >
Equations should be
0 punctuated,
o numbered, and
o ﬁtted within a single line if possible.
9 a or an? The rule is simple: Use a if the ﬁrst letter of the f(')llowing word
begins with a consonant when pr(’)no1.1need. Use an if the ﬁrst letter
of the f(')llowing word begins with a vowel sound (a, e, i, o, 11) when
pronounced. What do you use for the following?
UPS RS232 hour 1 k9 resistance 8 V potential diﬁerence illogical rule 10 Not and or 1. n0 drinking or no eating 2. drinking and eating prohibited 3. n0 drinking and no eating 4. drinking or eating prohibited 5. You may not eat or drink in this library. 6. Neither eating nor drinking is permitted. :> Attempt to use expressions that are logically correct and difficult
to misunderstand. 11 Pronouns In English7 the pronouns he and his are not neutral. Most native
speakers will prefer “Engineers represent their profession to the public.”7
over “An engineer represents his profession to the public.” 12 Hyphens Notice that compound words as in
“highvoltage supply” and
“low—voltage system77 have hyphens when they are adjectives. They do not have a hyphen
when used as nouns such as in “There was high voltage on the wires that were supposed
to carry low voltage.” There are many other rules regarding hyphens in the booklet. l3 Verb tense and voice As we discussed before, attempt to write using
0 the present tense and o the active voice. 14 Dates What does 10/12/06 mean?
0 Tenth of December 1906.
o Tenth of December 2006.
o Twelfth of October 2006.
0 Sixth of December 2010.
It is much better to write 10 December 2006. This method
conveys the correct meaning clearly and has a logical order (days then months then years). Summary There are many rules but they all guide you to
0 write logically correct sentences,
0 write grammatically correct sentences, and 0 write sentences that are difﬁcult to misunderstand. ...
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This note was uploaded on 04/09/2010 for the course ELECT. ENG 607 taught by Professor Hossamfahmy during the Spring '09 term at Cairo University.
 Spring '09
 hossamfahmy

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