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SARL Exam Cheat Sheet (DRAFT) by

SA Amatuer Radio League Exam

This is a draft cheat sheet. It is a work in progress and is not finished yet.

Units

pico
p
÷1 000 000 000 000
10-12
nano
n
÷1 000 000 000
10-9
micro
µ
÷1 000 000
10-6
milli
m
÷1 000
10-3
kilo
k
•1 000
103
mega
M
•1 000 000
106
giga
G
•1 000 000 000
109

Resistor Color Codes

Color
Digit
Multiplyer
Tolerance
Black
0
• 1
Brown
1
• 10
1%
Red
2
• 100
2%
Orange
3
• 1000
Yellow
4
• 10 000
Green
5
• 100 000
Blue
6
• 1 000 000
Violet
7
• 10 000 000
Grey
8
• 100 000 000
White
9
• 1 000 000 000
Gold
    
5%
Silver
    
10%
 

Ohm's Law

V = IR

Volts = Amperes • Ohms

Kirchoff's Laws

Kirchoff's Current Law:
I
IN
=I
OUT

Kirchoff's Voltage Law(1)
The voltage between any two points in a circuit is equal to the sum of the voltage drops along any path connecting those points
Kirchoff's Voltage Law(2)
The sum of the voltage drops around any closed circuit is zero

Resistors in Series

V
1
=IR
1
Ohm's Law
V
2
=IR
2


V
TOTAL
=V
1
+V
2
Kirchoff's Voltage Law
∴V
TOTAL
=IR
1
+ IR
2

∴V
TOTAL
=I(R
1
+R
2
)

Resistors in Parallel

I
1
=V/R
1
Ohm's Law
I
2
=V/R
2


I
TOTAL
=I
1
+I
2
Kirchoff's Current Law
∴I
TOTAL
=V/R
1
+ V/R
2


Applying Oh's Law to the whole circuit:
V/R
PARALLEL
=I
TOTAL
=V/R
1
+V/R
2

∴1/R
PARALLEL
=1/R
1
+1/R
2
 

Bands

160 Meter
1.8 MHz
80 Meter
3.5 MHz
40 Meter
7 MHz
20 Meter
14 MHZ
17 Meter
18 MHz
15 Meter
21 MHz
12 Meter
24 MHz
10 Meter
28 MHz
6 Meter
50 MHZ
2 Meter
144 MHz
144-146 MHz
70 cm
420 MHz
430-440MHz