G5A: Resistance; reactance; inductance; capacitance; impedance; impedance matching
G5A01:
What is impedance?
The opposition to the flow of current in an AC circuit
The electric charge stored by a capacitor
The inverse of resistance
The force of repulsion between two similar electric fields
G5A02:
What is reactance?
Opposition to the flow of alternating current caused by capacitance or inductance
Opposition to the flow of direct current caused by resistance
A property of ideal resistors in AC circuits
A large spark produced at switch contacts when an inductor is deenergized
G5A03:
Which of the following causes opposition to the flow of alternating current in an inductor?
Reactance
Conductance
Reluctance
Admittance
G5A04:
Which of the following causes opposition to the flow of alternating current in a capacitor?
Reactance
Conductance
Reluctance
Admittance
G5A05:
How does a coil react to AC?
As the frequency of the applied AC increases, the reactance increases
As the frequency of the applied AC increases, the reactance decreases
As the amplitude of the applied AC increases, the reactance increases
As the amplitude of the applied AC increases, the reactance decreases
G5A06:
How does a capacitor react to AC?
As the frequency of the applied AC increases, the reactance decreases
As the frequency of the applied AC increases, the reactance increases
As the amplitude of the applied AC increases, the reactance increases
As the amplitude of the applied AC increases, the reactance decreases
G5A07:
What happens when the impedance of an electrical load is equal to the internal impedance of the power source?
The source can deliver maximum power to the load
The source delivers minimum power to the load
The electrical load is shorted
No current can flow through the circuit
G5A08:
Why is impedance matching important?
So the source can deliver maximum power to the load
So the load will draw minimum power from the source
To ensure that there is less resistance than reactance in the circuit
To ensure that the resistance and reactance in the circuit are equal
G5A09:
What unit is used to measure reactance?
Ohm
Farad
Ampere
Siemens
G5A10:
What unit is used to measure impedance?
Ohm
Volt
Ampere
Watt
G5A11:
Why should core saturation of a conventional impedance matching transformer be avoided?
Harmonics and distortion could result
Magnetic flux would increase with frequency
RF susceptance would increase
Temporary changes of the core permeability could result
G5A12:
What is one reason to use an impedance matching transformer?
To maximize the transfer of power
To reduce power dissipation in the transmitter
To minimize SWR at the antenna
To minimize SWR in the transmission line
G5A13:
Which of the following devices can be used for impedance matching at radio frequencies?
All of these choices are correct
A transformer
A Pi-network
A length of transmission line
G5A14:
Which of the following describes one method of impedance matching between two AC circuits?
Insert an LC network between the two circuits
Reduce the power output of the first circuit
Increase the power output of the first circuit
Insert a circulator between the two circuits
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