Transcript Technical Basics - 1 Components

Chelmsford Amateur Radio Society
Intermediate Course
(3) Technical Basics - 1
Components
Chelmsford Amateur Radio Society
Intermediate Licence Course
Murray Niman G6JYB
Slide Set 3
(3) Technical Basics -1: Components
1
Electronic Components
•
Nature
Amateur Radio applies Electronics to Wireless Communication
•
Items
Common Electronic Components Include:
–
–
–
–
–
•
Resistors, inc Colour code
Capacitors, Inductors, Resonant Circuits
Diodes & LEDs
Transistors
Switches, Fuses, Connectors
The Intermediate Licence expects you to be able to recognise components,
their circuit symbols, and to build and test simple circuits
Chelmsford Amateur Radio Society
Intermediate Licence Course
Murray Niman G6JYB
Slide Set 3
(3) Technical Basics -1: Components
2
Electrical Units
Quantity
Voltage, V
Current, I
Resistance, R
Capacitance
Inductance
Power, P
Frequency, f
Wavelength, 
Chelmsford Amateur Radio Society
Intermediate Licence Course
Unit
Volt
Amp
Ohm
Farad
Henry
Watt
Hertz
Metre
Symbol
V
aka Potential Difference
A

F
H
W
Hz
m
Murray Niman G6JYB
Slide Set 3
(3) Technical Basics -1: Components
3
Unit Prefixes
Factor
trillionths
billionths
millionths
thousandths
thousands
millions
billions
SN
10-12
10-9
10-6
10-3
103
106
109
Prefix
pico
nano
micro
milli
kilo
Mega
Giga
Examples: 25kV = 25000V
0.1uH = 100nH
Chelmsford Amateur Radio Society
Intermediate Licence Course
Symbol
p
n
 or u
m
k
M
G
1500mA = 1.5A
2.45GHz=2450MHz
Murray Niman G6JYB
Slide Set 3
(3) Technical Basics -1: Components
4
Ohms Law
V Volts
I Amps
R Ohms
Relates Voltage, V Current, I
Resistance, R
V=IxR I=V/R R=V/I
Chelmsford Amateur Radio Society
Intermediate Licence Course
Murray Niman G6JYB
Slide Set 3
(3) Technical Basics -1: Components
5
Power
P Watts
V Volts I Amps
Relates Power, P
Voltage, V
P=VxI V=P/I I=P/V
Chelmsford Amateur Radio Society
Intermediate Licence Course
Murray Niman G6JYB
Current, I
Slide Set 3
(3) Technical Basics -1: Components
6
Cells & Batteries

•
Batteries provide a source of DC power
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Note symbols for Single Cells or Battery Packs
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Cells store electrical energy by chemical means
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Primary Cells can only be used once.
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Secondary cells can be recharged. This reverses
the chemical reaction eg in Lead Acid, NiCd, LiMH
•
Beware of Leakage, Shorts esp on Lead-Acid
•
Dispose of carefully
Chelmsford Amateur Radio Society
Intermediate Licence Course
Cell

+
Battery
Murray Niman G6JYB

Slide Set 3
(3) Technical Basics -1: Components

7
Resistors
•
Fixed Resistors traditionally
identified by Colour Code for
Value & Tolerance
•
Note that the modern BSI
Symbol is preferred to the
zigzag
Resistor
No
•
Note all the symbols opposite
for the various forms
•
Check Wattage Rating
Chelmsford Amateur Radio Society
Intermediate Licence Course
Preset
Resistor
Potentiometer
Murray Niman G6JYB
Variable
Resistor
Slide Set 3
(3) Technical Basics -1: Components
8
Resistor Colour Code
•
First two Bands
give Value Digits
•
Third Band is the
Multiplier for
Factor of Ten
•
Fourth Band is
Tolerance
•
Example:-
12 x1000= 12k, 10%
Chelmsford Amateur Radio Society
Intermediate Licence Course
Murray Niman G6JYB
Slide Set 3
(3) Technical Basics -1: Components
9
Resistors in Series/Parallel
•
Resistors in Series:-
Rtotal = R1+ R2+ R3 . . .
R1
•
R2
R3
Resistors in Parallel:-
1/Rtotal = 1/R1+1/R2+1/R3 . . .
•
For Identical Resistors this simplifies to...
•
For Two Resistors:
Rtotal = R/2
R2
•
For Three Resistors:
Rtotal = R/3
R3
Chelmsford Amateur Radio Society
Intermediate Licence Course
Murray Niman G6JYB
R1
Slide Set 3
(3) Technical Basics -1: Components
10
Inductors & Transformers
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Inductors are Coils which may be air or
ferrite cored
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Inductance is in Henries eg mH, nH, pH
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Inductance is proportional to number of
turns, diameter, core etc
•
Energy is stored in the magnetic field
•
They pass DC but increasingly block AC
at higher frequencies
•
Inductor
Iron-Cored
Inductor
Transformer
Pairs of coils can be used to create
Transformers
Chelmsford Amateur Radio Society
Intermediate Licence Course
Murray Niman G6JYB
Slide Set 3
(3) Technical Basics -1: Components
11
Capacitors
•
Capacitors are insulated plates, which
can store electric charge
•
Larger plate areas, or smaller
separation will give higher capacitance
•
Capacitance is in Farads eg uF, nF, pF
•
They block DC but increasingly pass
AC at higher frequencies
•
Beware Voltage rating and polarity of
Tantalum/Electrolytic versions
•
Note all the symbols opposite
Chelmsford Amateur Radio Society
Intermediate Licence Course
Murray Niman G6JYB
Capacitor
Variable
Capacitor
Polarised
Capacitor
Slide Set 3
(3) Technical Basics -1: Components
12
Diodes
•
Diodes are PN Junctions which only pass
current one way
•
Diodes are a key item in PSUs where they
rectify AC into DC
•
Note Forward Current and Reverse Voltage
ratings, and small forward Voltage Drop
•
LEDs - Light Emitting Diodes
•
Variable Capacitance Diodes - use PN Jn
Capacitance
•
Zener Diodes - have a precise Reverse Voltage
Chelmsford Amateur Radio Society
Intermediate Licence Course
Murray Niman G6JYB
Diode
LED
Varicap Diodes
Slide Set 3
(3) Technical Basics -1: Components
13
Transistors
•
•
•
Bipolar Transistors have NPN or
PNP junctions
Middle section is the ‘Base’. A small
bias current can control a larger
flow between Collector and Emitter
b
e
NPN Transistor
Current Flow is controlled
Electrostatically in FET devices
•
Transistors can Amplify or Switch
- or Oscillate
•
Integrated Circuits have arrays of
Transistors on a single chip
Chelmsford Amateur Radio Society
Intermediate Licence Course
Murray Niman G6JYB
c
d
g
s
P-Channel
Field Effect Transistor (FET)
Slide Set 3
(3) Technical Basics -1: Components
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Miscellaneous
•
Also need to recognise symbols for
Switches, Grounds, Crystals etc, etc
Switch
SPST
Antenna
Switch
DPST
Crystal
Loudspeaker
Fuse
Earth
Chelmsford Amateur Radio Society
Intermediate Licence Course
Chassis
Lamp
Murray Niman G6JYB
Earphone
Microphone
Slide Set 3
(3) Technical Basics -1: Components
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Practical
• Recognise Resistors by Colour Code
• Measure Resistors in Series
• Measure Resistors in Parallel
• Learn to Recognise other Components
• Soldering - correctly without damage
Chelmsford Amateur Radio Society
Intermediate Licence Course
Murray Niman G6JYB
Slide Set 3
(3) Technical Basics -1: Components
16