Chapter 17: Resonance Circuits
MULTIPLE CHOICE
1. When a circuit is purely resistive the phase angle is ____ because voltage and current are in phase.
a.
zero
c.
90
b.
45
d.
180
2. When a circuit contains pure reactance with no resistance the phase angle will increase to ____
degrees.
a.
60
c.
120
b.
90
d.
180
3. Current flow is the same through all components in ____ circuits.
a.
series
c.
series-parallel
b.
parallel
d.
all
4. In a capacitive circuit, the voltage lags 90 degrees behind the current, so its voltage vector (EC) is
drawn ____.
a.
upward
c.
leftward
b.
downward
d.
rightward
5. Parallel circuits containing inductors and capacitors may be analyzed with vector diagrams; the vectors
used are ____ vectors.
a.
inductance
c.
current
b.
capacitance
d.
voltage
6. The impedance of a parallel RL or RC circuit is ____ both the individual resistance or reactance.
a.
smaller than
c.
equal to
b.
greater than
d.
the sum of
7. A circuit containing just pure inductance shows current lagging voltage by ____ degrees.
a.
30
c.
90
b.
60
d.
180
8. The ratio of true power in watts to apparent power in volt-amps is called the ____.
a.
true factor
c.
power factor
b.
apparent factor
d.
watts/volt-amps factor
9. In a pure resistive circuit, the true power is the same as the apparent power, so the power factor is
____.
a.
zero
c.
two
b.
one
d.
three
10. In a pure inductive or capacitive circuit the true power is zero, no matter what the apparent power is,
so the power factor is ____.
a.
zero
c.
positive
b.
one
d.
negative
COMPLETION
1. The combined effect of resistance and reactance is called ____________________ and is represented
by the symbol Z.
2. As opposed to true power, the figure obtained by multiplying the source voltage and current is known
as ____________________.
3. If both inductive and capacitive components are in an AC circuit, at one particular frequency their
reactances will be equal but opposite. This condition is referred to as ____________________.
SHORT ANSWER
1. Discuss some of the applications of resonant circuits.
2. Discuss how the value of inductance and capacitance affects the frequency of resonance of a circuit.
