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EE possible Finals Exam
A series circuit consists of an impedance coil having a
resistance of 55 ohms and an inductance of 0.281 henry,
and a 25-ufcapacitor. (a) Calculate the resonant frequency.
For the condition of resonance, and an impressed emf of
110 volts, determine (b) the total current and power; (c)
the voltage drops across the impedance coil, the capacitor,
and the resistor.
A series R-L-C circuit is to be made resonant when
connected to 2 208-volt If the inductance is 0.0396 henry,
determine the capacitance of the capacitor and the
minimum ohmic value of the resistor if the voltage drop
across the capacitor is to be limited to 600 volts.
Calculate the circuit current in Prob. 2 (a) if the frequency
is reduced to 350 cps, (b) if the frequency is raised to 450
cps.
A series circuit consisting of a 16-ohm resistor, a 79.5-uf
capacitor, and a variable inductor is connected to a 116volt 50-cycle source. (a) For the condition of resonance
calculate the inductance, current, and voltage drop across
the inductor; (b) determine the inductance, current, and
voltage drop across the inductor when the voltage drop
across the latter is a maximum.
An impedance coil takes 144 watts at a lagging power
factor of 0.6. What values of capacitance and resistance
should be connected in series with the coil if the power
input to the latter is to remain unchanged and the overall
circuit power factor is to be unity? The circuit is energized
by a 120-volt 60-cycle source.
Determine the resonant frequency and the impedance of
a series circuit consisting of a 5-ohm resistor, a 250 X 10euf capacitor, and a 127.5 X 10- henry inductor. (b) What
will be the resonant frequency and impedance if the values
are changed to 7.2 ohms, 125 X 10-6 uf, and 255 X 10henry?
A series circuit consisting of a 16-ohm resistor, a 0.1275henry inductor, and e variable capacitor is connected to a
116-volt 50-cycle source. (a) For the condition of resonance
calculate the capacitance, current, and voltage drop across
the capacitor; (b) determine the capacitance, current, and
voltage drop across the capacitor when the voltage drop
across the latter is a maximum.
n/a
n/a
A series R-L-C circuit has a Q of 75 and a pass band between
half-power frequencies of 160 cps. Calculate the frequency
of resonance and upper and lower
A variable capacitance C is connected in parallel with an
impedance coil having a resistance of R ohms and an
inductance of L henrys. For the condition of resonance,
derive an expression for C in microfarads in terms for R, and
L.
An impendence coil having a resistance of 25 ohms and an
inductance of 20 mh is connected in parallel with a variable
capacitor. a) For what value of C will the circuit be resonant
if a 90-volt 400-cycle source is applied? (b) What will be the
line current under this condition?
If a 7-uf capacitor is connected in parallel with the coil of
Prob. 12, what adjusted frequency will cause the circuit to
be resonant?
A variable inductive reactance XL is connected in parallel
with a series com- bination of resistance R and a capacitive
reactance Xc. For the condition of resonance derive an
expression for Xi in terms of R and Xc.
A series circuit consisting of a 30-ohm resistor and a 4-f
capacitor is connected in parallel with a variable inductor.
For what value of inductance will the circuit be in
resonance if the frequency of the source is 1,200 cps?
An impedance coil having a resistance of 30 ohms and 50cycle inductive reactance of 33.3 ohms is connected to
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125-volt 60-cycle source. A series circuit consisting of 20ohm resistor and a variable capacitor is then connected in
parallel with the coil (a) For what values of capacitance will
the circuit be in resonance? (b) Calculate the two values of
line current for the condition of resonance
Calculate the resonant frequency of a two-branch parallel
circuit given the following particulars: R - 30 ohms, c = 30
ohms, L = 0.106 henry, C = 48 uf.
18. Calculate the resonant frequency of the two-branch
parallel circuit given the following particulars: R: = 20
ohms, Rc - 20 olun, L - 0.106 henry, € - 365 rf.
An impedance coil having a resistance of 20 ohms and an
inductance of 4 mh is connected in parallel with a 0.4f
capacitor. Calculate the resonant frequency (a) taking the
resistance into account, b) neglecting the resistance.
The following data are given for a two-branch parallel
circuit: E - 120, R3 = 30, X2 - 25, Xo - 40 Calculate the value
of Ro that will make the circuit resonant, and determine
the total current and power under this condition
A 20,000-cycle source is connected to a series circuit
consisting of a 50-ohm resistor and 0.266- capacitor. An
impedance coil, whose resistance and inductance are 25
ohms and 0.191 mb, respectively, is then connected in
series with a variable resistor, site which the combination
is paralleled with the B-C circuit. For what value of the
variable resistor will the entire circuit be in resonance?
A parallel-series filter like that of Fig. 13.106 is to be
designed to pass a wave having a frequency of 3,500 cps
and block a 2,500-ops way. The series inductor has a value
of 0.0023 henry. Calculate the capacitance of the series
capacitor and the parallel inductor.
It is desired to design a series parallel type of filter like that
shown in Fig. 13-100 to pass # 20,000-cycle wave and block
a 30,000-cycle wave. If the capacitance of the parallel
capacitor C, is 0.015 uf, determine the values of L and C
An impedance coil has a resistance of 60 ohms and an
inductance of 0.144 henry. What series combination of
Rand should be connected in parallel with the coil to make
the circuit resonant at all frequencies?
An impedance coil whose resistance and inductance are 18
ohms and 8.82 mh, respectively, is connected in parallel
with a series combination of a 5.3- capacitor and a variable
resistor. For what value of resistance will the circuit be in
resonance at 1,000 cps?
An impedance coil having a resistance of 15 ohms and an
inductance of 0.08 henry is connected in series with a
variable capacitor. If a 117-volt 60-cycle source is
connected to the circuit, what will be the capacitate of the
capacitor and the current (a) when the circuit is in
resonance (b) when the voltage drop across the coil and
the capacitor are equal?
A 400-ohm resistor, a 20-y capacitor, and 0.505 henry
inductor are connected in parallel and energized by - 240volt variable frequency source. (a) At what frequency will
the circuit be in resonance? (b) Calculate the line current Is
and the individual unit currents In, and Je under conditions
of resonance
15.9-uf capacitor and & 15.1-mh inductor are connected in
parallel. In series with these units are & variable resistor R
and an adjustable device X, joined in series. (a) Determine
the kind and size of device X (inductance in henrys or
capacitance io microfarads) when the circuit is connected
to a 50-volt 400-cycle source and is adjusted to resonance.
(b) For the resonant condition calculate the value of R if the
voltage drop across the paralleled units is to be 100 volts.