3. Technical Basics
3a Units of measurement and multiple/sub-multiple
prefixes.
3a.1 Recall the units and abbreviations for potential
difference, current, power, resistance, capacitance, inductance and frequency.
The ILC will be taking you much much deeper into electronic theory than the
FLC and the course will assume that you have a good working knowledge of
all of the FLC technical basics. Some revisions will be given but mainly
the ILC will be new information that needs to be fully understood stage by
stage before passing onto the next part. So don't rush your learning and
remember to chat to your course tutor about anything that is not clear. Even
if you think that you are asking a silly question "ASK IT" !!
In this part of the syllabus is going over
five items that you learned (or should have learned) in the FLC
and only introducing two new items.
However it has come to our notice that some students do not know
the units of resistance, inductance, capacitance etc. These unit
must be learned so that they are second nature to you so that
in a question such as :-
The value of a capacitor is given in ? You readily know to
tick the box next to Farads.
Quantity |
Symbol |
Units |
Comment |
Potential Difference |
V |
Volts (V) |
Learned in FLC |
Current |
I |
Amps (A) |
Learned in FLC |
Resistance |
R |
Ohms
|
Learned in FLC |
Power |
P |
Watts (W) |
Learned in FLC |
Frequency |
f |
Hertz (Hz) |
Learned in FLC |
Capacitance |
C |
Farad (F) |
New for ILC |
Inductance |
L |
Henry (H) |
New for ILC |
Recall and understand the prefixes pico, nano, micro,
milli, kilo, Mega and Giga.
In the FLC you learned about milli kilo and Mega - m,k,M so there are four
new ones to learn.
Prefix |
Prefix Name |
Scaling |
Example |
Comment |
p |
pico |
1/1,000,000,000,000 |
0.000000000001 |
1pF |
1 pico farad |
New for ILC |
n |
nano |
1/1,000,000,000 |
0.000000001 |
1nF |
1 nano farad |
New for ILC |
u |
micro |
1/1,000,000 |
0.000001 |
1uF |
1 micro farad |
New for ILC |
m |
milli |
1/1,000 |
0.001 |
1mA |
1 milli amp |
Learned in FLC |
|
1 |
|
k |
kilo |
1000 |
1k |
1 kilo ohms |
Learned in FLC |
M |
Mega |
1,000,000 |
1M |
1 mega ohms |
Learned in FLC |
G |
Giga |
1,000,000,000 |
1GHz |
1 giga hertz |
New for ILC |
|
Some students find it difficult to convert down the scale from larger to
smaller numbers when it is less than 1 -- perhaps the following
will help.
-
1
-
0.001
-
0.000001
-
0.000000001
-
0.000000000001
|
-
Unit
-
milli
-
micro
-
nano
-
pico
|
-
1 = 1
-
1000 milli = 1
-
1000 micro = 1 milli
-
1000 nano = 1 micro
-
1000 pico = 1 nano
|
Try to see the pattern in the numbers and write out how to
convert from one to another in the way you can understand.
Try with the example below. To start with always relate the number to 1 |
Example
Convert 0.001 micro to nano farads ? |
So relative to 1 farad we have from above :-
1 micro farad = 0.000001
Thus relative to 1 farad 0.001 micro farads = 0.00000001
we have added the extra 3 zeros one for the decimal
point and the other two from the 001
We now have 8 zeros
from above we know that
relative to 1 farad that 1 nano farad = 0.000000001
that is 8 zeros so 0.001 micro farads = 1 nano farads. |
A student (from an early course who has now progress to an Advanced licence)
suggested the following to help you remember the order down from the biggest
to the smallest,
Goal Makers Kick Once Many Underestimate Noise Pollution
Goal = Giga
Makers = Mega
Kick = kilo
Once = 1
Many = milli
Underestimate = u for micro
Noise = nano
Pollution = pico
At Intermediate level you need to recall the Engineering Notation for key
units and sub-units and be able to change between them, but there will be
no calculations requiring you to use the notation.
The three zero steps in the units and sub-units translate into changes of
x 103 with each level of unit or sub-unit:
Giga = x 109
Mega = x 106
Kilo = x 103
Milli = x 10-3
Micro = x 10-6
Nana = x 10-9
Pico = x 10-12
However at Intermediate level you need to recall the Engineering Notation
for key units and sub-units and be able to change between them, but there
will be no calculations requiring you to use the notation. |