problem set in elcitwo_1
TRANSCRIPT
7/23/2019 Problem Set in Elcitwo_1
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PROBLEM SET IN ELCITWO (Energy Storage Devices, Impedance, Reactance, Series RLC)
1.
A 15.0-microfarad capacitor is connected to a 120V, 60 Hz source. What are (a) the capacitive
reactance and (b) the current (rms and peak) in the circuit? (Ans.177ohms, 0.678A, 0.959 A,
respectively)
2.
A 125-millihenry inductor is connected to a 120-volt, 60 Hz source. What are (a) the inductive
reactance and (b) the rms current in the circuit? (Ans. 47.1 ohms, 2.55 A)
3.
A series RC circuit has a resistance of 100-ohms and a capacitance of 15uF. (a) What is the (rms)
current in the circuit when driven by a 120V, 60Hz source? (b) Compute the (rms) voltage across
each circuit element and the two elements combined. (Ans. 0.591A, VR=59.1V,VC=105V)
4.
A series RLC circuit has a resistance of 25.0 ohms, a capacitance of 50uF and an inductance of
0.3H. If the circuit is driven by a 12V, 60Hz source, what are (a) the impedance of the circuit, (b)
the current in the circuit, and (c) the phase angle between the current and the voltage? (Ans.64.9 ohms, 1.85A, 67.3
o
)
5.
A 15uF capacitor has a voltage of 5V across it at t=0. If a constant current of 25mA flows through
the capacitor, how long will it take for the capacitor to charge up to 150uC? (Ans. t = 3ms)
6.
The model of an electric motor consists of a series combination of a resistor and inductor. A
current i(t) = 4te-tA flows through the series combination of a 10-ohm resistor and 0.1H
inductor. Find the voltage across the combination. (Ans. v(t) = 0.4e-t + 39.6 te
-t V)
7.
The voltage, v(t), across a 25mH inductor used in a fusion power experiment is v(t) = 0 when t <
0 and v(t) = 6 cos 100t when t > 0 where the units of time are s and the units of voltage are V.
The current in this inductor is zero before the voltage changes at t=0. Determine the power p(t),
absorbed by the inductor and the energy w(t), stored in the inductor. (Ans. p(t)=7.2sin200t W,
w(t)=3.6[1-cos200t] mJ)