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ap erap eru ou o
AmplifierAmplifier
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that amplifies low-power audio signals
between 20 - 20 000 Hz, the human range
loudspeakers and is the final stage in a
.
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Consist of :-
y Pre-Amplifiers
y Tone Control Networks
y Driver Amplifiers
y Power Amplifier
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Block Diagram FunctionBlock Diagram Function
y Input transducer
y Microphone - a transducer which converts sound to
e ectr ca s gna .
y Amplifies the small audio signal (voltage) from the
microphone.
y Tone Control amplifier :
Adjust the nature of the audio signal. The tone controladjusts the balance of high and low frequencies. The volume
Normally has few button such as volume, bass, treble anecho.
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y Driver amplifier :
y Strengthen the signal received from the tone
control circuit
y Power Amplifier :
Amplify the signal from the driver amplifier to
a suitable value, so that it can drive the.
y pea er A transducer which convert the electrical
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Pre-amplifier Tone Control Amplifier Power Amplifier
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y There are 4 t e of Power Am lifier
circuit :- Sin le ended
Push pull
Com lementar s mmetr
Integrated circuit
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Sin le Ended Circuit
Q1
a
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y
Transistor Q1 open/short no sound/ nopower supply.
y Capacitor C1 open/ short no input signal
y Resistor Ra open/short no sound/ no powersupp y
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Push Pull Circuit
R1
R2
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y Transistor TR1 atau TR2 :
pintas-keluaran bererutan amplitud rintangan R1 & R2terbakar.
er u a- ereru an amp u
y an :
pintas/terbuka tiada suara
y Perintang pincang :
-
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Possible Faults in ComplementaryPossible Faults in Complementary
ymme ryymme ry
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Complementary Symmetry
y Transistor keluaran: Sekali imbas kita perhatikantransistor-transistor keluaran di sambung terus dari bekalanmelalui rintan an-rintan an rendah dan ke bumi. ika di beripincang ,transistor berfungsi penuh iaitu mengalirkan arusmaksimum.Ini membebankan transistor keluaran.Oleh itu
kerosakan yang paling kerap berlaku ialah pada transistor.
y Keadaan kerosakan, boleh terbuka atau terpintas.Setengah-
sambungan bekalan ke transistor keluaran.Jika salah satutransistor keluran terpintas atau terbuka ,keluaran menjadibererutan atau tidak berfungsi langsung.
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y Public address or PA system is a combination of a set of audio
.
y Often used in schools and office buildings, PA systems can be used
for announcements or emergency information and provide a simple
way to get information out quickly.
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y P.A S stem can be divided b two
parts which is
Low Level System
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y Basic PA systems are consist of :-
Loudspeakers
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