B-003-17: Power supply fundamentals
B-003-17-01:
If your mobile transceiver works in your car but not in your home, what should you check first?
The power supply
The speaker
The microphone
The SWR meter
B-003-17-02:
What device converts household current to 12 VDC?
A power supply
A low pass filter
An RS-232 interface
A catalytic converter
B-003-17-03:
Which of these usually needs a heavy-duty power supply?
A transceiver
An antenna switch
A receiver
An SWR meter
B-003-17-04:
What may cause a buzzing or hum in the signal of an AC-powered transmitter?
A bad filter capacitor in the transmitter's power supply
Using an antenna which is the wrong length
Energy from another transmitter
Bad design of the transmitter's RF power output circuit
B-003-17-05:
A power supply is to supply DC at 12 volts at 5 amperes. The power transformer should be rated higher than:
60 watts
17 watts
2.4 watts
6 watts
B-003-17-06:
The diode is an important part of a simple power supply. It converts AC to DC, since it:
allows electrons to flow in only one direction from cathode to anode
has a high resistance to AC but not to DC
has a high resistance to DC but not to AC
allows electrons to flow in only one direction from anode to cathode
B-003-17-07:
To convert AC to pulsating DC, you could use a:
diode
transformer
capacitor
resistor
B-003-17-08:
Power-line voltages have been made standard over the years and the voltages generally supplied to homes are approximately:
120 and 240 volts
110 and 220 volts
100 and 200 volts
130 and 260 volts
B-003-17-09:
So-called "transformerless" power supplies are used in some applications (notably tube-type radios and TV receivers). When working on such equipment, one should be very careful because:
one side of the line cord is connected to the chassis
DC circuits are negative relative to the chassis
chassis connections are grounded by the centre pin of the power source's plug
the load across the power supply is variable
B-003-17-10:
If household voltages are consistently high or low at your location, this can be corrected by the use of:
an autotransformer
a full-wave bridge rectifier
a variable voltmeter
a proper load resistance
B-003-17-11:
You have a very loud low-frequency hum appearing on your transmission. In what part of the transmitter would you first look for the trouble?
the power supply
the variable-frequency oscillator
the driver circuit
the power amplifier circuit
|
Color key:
|
|
● = Unseen
|
|
● = Weak
|
|
● = Review
|
|
● = Learned
|
|
● = Incorrect answer
|
