Dc voltages – Elenco AM/FM Radio Kit User Manual
Page 40
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1. The number of cycles produced per second by a source
of sound is called the ...
r
A) amplitude.
r
B) vibration.
r
C) sound wave.
r
D) frequency.
2. The radio frequencies used by AM broadcast stations
are between ...
r
A) 20kHz and 400kHz.
r
B) 5kHz and 20kHz.
r
C) 2400kHz and 6000kHz.
r
D) 550kHz and 1600kHz.
3. The process of removing the audio wave from the radio
wave is called ...
r
A) demodulation.
r
B) frequency reduction.
r
C) modulation.
r
D) vibrating.
4. When an electromagnetic wave (modulated radio
wave) passes an antenna, it ...
r
A) induces a voltage and current in the
antenna.
r
B) changes an audio wave into a radio wave.
r
C) changes the carrier frequency.
r
D) produces sidebands.
5. The power of the signal transmitted by the broadcast
station and the distance, the signal travelled from the
transmitter to the receiver, determine the ...
r
A) frequency of the modulation.
r
B) wavelength of the audio waves.
r
C) amount of signal picked up by the antenna.
r
D) type of filter that is used.
6. When the two metal plates on a variable capacitor are
unmeshed the ...
r
A) capacitance is minimum.
r
B) capacitance is maximum.
r
C) capacitance is not affected.
r
D) inductance is increased.
7. The process of mixing two signals to produce a third
signal is called ...
r
A) filtering.
r
B) detecting.
r
C) rectification.
r
D) heterodyning.
8. The magic wand is used to determine ...
r
A) whether more or less inductance is required
in a tuned circuit.
r
B) whether more or less capacitance is
required in a tuned circuit.
r
C) the gain of an RF amplifier.
r
D) whether the oscillator is functioning.
9. The IF frequency of your AM radio is ...
r
A) 1600kHz.
r
B) 455kHz.
r
C) 550kHz.
r
D) 910kHz.
10. The purpose of the AGC circuit is to ...
r
A) automatically control the frequency of the
oscillator circuit.
r
B) control the band width of the IF stages.
r
C) reduce distortion in the audio circuit.
r
D) maintain a constant audio level at the
detector, regardless of the strength of the
incoming signal.
QUIZ - AM RADIO SECTION
INSTRUCTIONS: Complete the following examination, check your answers carefully (answers on previous page).
DC VOLTAGES
The voltage readings below should be used in troubleshooting the AM section (switch at AM position).
Q7
B
1.5
E
1.0
C
8.8
TP5 (AGC)
1.4
Q8
B
1.4
E
0.8
C
8.8
Q9
B
1.7
E
1.0
C
9.0
U1
1
1.3
2
0
3
0
4
0
5
4.5
6
9.0
7
4.4
8
1.3
TP1
4.5
Q10
B
0.7
E
0.06
C
3.1
Q11
B
4.2
E
3.7
C
8.4
Q12
B
3.1
E
3.7
C
0.6
Q13
B
8.4
E
9.0
C
3.7
Q14
B
0.6
E
0
C
3.7
TP19
3.7
1. Volume set to minimum.
2. Connect side of capacitor C29 (that goes to L4)
to TP15 with a jumper wire.
3. Battery voltage = 9V
4. All voltages are referenced to circuit common.
5. Voltage readings can vary +10%
Test Conditions